Naming convention for multiple star systems

Naming convention for multiple star systems

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Okay, so I've seen different notations for the stars in β Capricorni. Some sources state that the stars are Aa, Ab1 and Ab2, Ba, and Bb, while others say that they are Aa, Aba and Abb, Ba, and Bb. So, what is the proper way to name stars in a multiple star system, and are there any exceptions to this convention?

The purpose of the notation is to indicate how the system is physically constructed, to indicate which stars orbit which - especially useful in hirachically organized stellar systems. So both ways are correct as their meaning is understood.

The notation I encounter most often is the first one you indicate: indicating with capital letters the systems which orbit the common pericenter of the overall system. With non-capital letters the components of the upper level are distinguished. And keeping it more readable, numbers are used for the 3rd level if further distinction is needed for a 3rd level.

However this nomenclature is not unique - and there is so far no general consensus. See the Washington Multiplicity Catalog for a take on getting some order at a given time and the IAU working group on stellar names. For a given system the designation might be more traditional and depend on order of discovery and naming by discoverer than following a fixed scheme. See also the discussion of future nomenclature on stellar system components in the corresponding wiki article.

I suppose that the International Astronomical Union has rules for naming stars in multiple systems.

I believe the usual rule is to describe the brighter star as A and the dimmer star as B, which works well as long as neighter star is very variable.

Thus the brighter star in Alpha Centauri is Alpha Centauri A and the less bright star is Alpha Centauri B. Sometime later a very dim red dwarf was discovered close to Alpha Centauri A & B, and became known as Alpha Centauri C, or Proxima Centauri since it is the closest star to our solar system. I think that recent research has shown that Alpha Centauri C is actually gravitationally bound to A and B and part of their star system.

I also know that when exoplanets are found orbiting stars the exoplanets are usually given lower case Latin letters, starting with b for the first exoplanet discovered. And there is an exception when several exoplanets are discovered orbiting the same star at the same time. In that case they are designated b, c, d, etc. in order of increasing distance from the star. And if more exoplanets are later discovered in the system, planet e could orbit between planets b and c, for example.

That is different from the system in science fiction stories where it is normal to designate exoplanets with Roman numerals in order of increasing distance from their star, so that in our solar system Mercury is sometimes called Sol I, Venus is sometimes called Sol II, Earth is sometimes called Sol III, and so on.

Castor, or Alpha Geminorum, is a sextuple star system, with visible three stars which are spectroscopic binaries. That means that telescopes show three Castor stars as dots of light, but the spectra of each star shows that it is actually a close binary star with two stars revolving around each other and thus changing their doppler shifts relative to Earth.

Castor is a multiple star system made up of six individual stars; there are three visual components, all which are spectroscopic binaries. Appearing to the naked eye as a single star, Castor was first recorded as a double star in 1718 by James Pound, but it may have been resolved into at least two sources of light by Cassini as early as 1678. The separation between Castor A and Castor B has increased from about 2" (2 arcseconds of angular measurement) in 1970 to about 6" in 2017.[18][16] These two binary pairs have magnitudes of 1.9 and 3.0.[1]

So sometime in or after 1718 the two brightest strs in Castor were labeled Castor A and Castor B. Sometime later the third visible star was discovered and named castor C, or Alpha Geminorum C.

When the three stars A, B, & C were discovered to be spectroscopic binaries, the two stars in each pair were give lower case letters a & b, so the six stars are now named Castor Aa and Ab, Castor Ba and Bb, and Castor Ca and Cb. That doesn't conflict with the system of naming exoplanets as long as any expolanets in the Castor system orbit Castor Aa, Castor Ba, or Castor Ca. but if exoplanets are found orbiting Castor Ab, Castor Bb, or Castor Cb, I'm not certain how they would be labeled.

Fortunately the orbital periods of Castor Aa & Ab, and Castor Ba & Bb, are only a few days long, and the orbital period of Castor Ca & Cb is less than a day. Thus most exoplanets found in the Castor system would probably orbit around both the stars in a pair. And I am not certain how such circumbinary exoplanets would be labeled. Probaly as Castor A b, c, d, etc. Caster C c, d, e, etc. and so on.

So I think that with the present system there is a possibility of ambiguous labeling, and people being uncertain whether Castor Ab, for example, is a star or an exoplanet.

I note that the original question mentions stars labeled with an Arabic number as part of a multiple system. And I never heard of that before.

And no doubt an astronomer who studies multiple stars can give a much better explanation of the naming conventions.

The Strange Naming Conventions of Astronomy

If you’ve spent time around the astronomical literature, you’ve probably heard at least one term that made you wonder “why did astronomers do that?” G-type stars, early/late type galaxies, magnitudes, population I/II stars, sodium “D” lines, and the various types of supernovae are all members of the large, proud family of astronomy terms that are seemingly backwards, unrelated to the underlying physics, or annoyingly complicated. While it may seem surprising now, the origins of these terms were logical at the time of their creation. Today, let’s look at the history of a couple of these terms, to figure out why astronomers did that.

Stellar Spectral Types
All stars have assigned spectral types. From the hottest to coldest, these types are O, B, A, F, G, K, M, L, T, and Y our sun is on the hotter end of the G spectral type. It looks like there might be some order here: B and A are next to each other, as are F and G. Then why is O way over on the hot end?

These spectral types have their origins in the late 19th century. In 1877, Edward Charles Pickering assembled a team of women to analyze astronomical data, a story that Ann Druyan, Neil DeGrasse Tyson, and the rest of the Cosmos team recently discussed. [Go read that article. No, really. I’ll wait.] One of these women, Williamina Fleming, classified the vast majority of these stars based on the depth of the hydrogen absorption lines observed in the stellar atmospheres. A stars had the deepest lines, while M, N, and O stars had essentially no lines. An entirely reasonable system, based off the observational data at hand.

Hydrogen absorption lines (marked) in visible light. A stars have the deepest lines, while the hydrogen lines of M dwarfs are barely visible. Image from RIT Physics.

Unfortunately, physics got in the way. These lines form in the presence of hydrogen transitions to the n=2 excited state. Hydrogen at this energy level is in abundance for A stars, but photons escaping from hotter O stars have so much energy they excite these atoms immediately, while M dwarf photons have so little energy they excite hydrogen to these higher levels very rarely. As a result, these lines are very strong at intermediate stellar temperatures. This was worked out by Antonia Maury and Annie Jump Cannon from 1897 to 1901 the latter of these two was the one to rearrange and reduce Fleming’s system into the now-familiar seven letters. With the discovery of the first brown dwarfs in the 1990s, the L, T, and Y spectral types have been added, again, in decreasing temperature.

The traditional measure of brightness in astronomy is the magnitude. The magnitude is a logarithmic scale, like the Richter or decibel scales. Unlike these scales, however, it is normalized such that a factor of 100 increase in flux corresponds to a change of five magnitudes. Oh, and it’s backwards: the fainter an astrophysical object, the larger its magnitude. With our modern understanding of photons and radiative flux, this system falls somewhere between annoying and nonsensical. Yet in its beginnings, there is reason! For these origins, we have to visit ancient Greece and the astronomer Hipparchus, who we find in the second century BCE. In addition to being one of the first dynamicists (dude was the first to measure the eccentricity of Earth’s orbit and the precession of the equinoxes, and calculated the length of the year to within six minutes), Hipparchus developed a catalog of stellar positions and brightnesses, creating the field of astrometry. (The astrometric Hipparcos mission of the 1990s was named after him). He gave numbers to each star corresponding to the brightness he observed, from 1 to 6. Each step was designed to correspond to an equal decrease in brightness.

The eye wasn’t well-understood at the time, but we now know the eye is a logarithmic tool. This was proven in the 19th century by Ernst Heinrich Weber and Gustav Theodor Fechner. The former proved that a small observed change in measured brightness is a function of the brightness ratio between two sources (mathematically, that for two sources A and B, δm = A/B). The latter turned Weber’s findings into a scale that relates the true magnitude of a stimulus to its perceived intensity, showing the relation to be logarithmic.

With the knowledge of the Weber-Fechner laws, it is clear to us that Hipparchus’ magnitudes correspond to a logarithmic system in flux. Unfortunately, these laws weren’t fully understood for 2000 years after the beginnings of this system. As a result, the magnitudes stuck. The system was refined in the 19th century: without any instruments more sophisticated than his eyes, Hipparchus’ original definitions were fairly arbitrary. In 1856, Oxford’s Norman Pogson proposed defining the magnitude such that five magnitudes of difference corresponded to a factor of 100 difference in flux. As a consequence, one magnitude corresponded to a factor of approximately 2.5 in flux this is the system still in use today.

Have a favorite astronomy quirk that I missed? Curious about some unit? Want to share a cool historic naming convention story? (One of my personal favorites is the origin of the calcium “H” and “K” lines.) Let us know in the comments, and your suggestions could feature in a follow-up article!

Billions and billions of stars

The great thing about our galaxy, the Milky Way, is that it is home to about 300 billion stars.

All of those stars mean a nearly endless supply of merchandise for companies to sell.

There are several companies offering to sell you a star name, and at many different prices.

One company says it has "named 2 million stars" since 1979, and its current package for a single star name starts at $110.

It does say that any name purchased is "not scientific but symbolic".

If you read the fine print of many other companies they usually say that astronomers do not officially recognise the name of the star you just purchased.

But that's not the only issue I've encountered. Remember, there are many companies selling star names.

In the span of one month, two entirely unrelated people contacted us to look at a star that they purchased. It was the same star. These two people had each paid to name the same star.

Names needed in 20 distant solar systems

Registered clubs and non-profit organizations are invited to submit proposals to the International Astronomical Union (IAU) and Zooniverse in the first-ever NameExoWorlds contest. Register here. This is the first time the public has been invited to name exoplanets, and also, for the first time in centuries, to give popular names to some stars — those that have known exoplanets in orbit around them. There are 15 stars and 32 planets (47 objects in total) available for naming. The name of the 20 host stars are explained and personal messages from some discoverers are also available here.

The list of the 20 ExoWorlds can be found here. Some of them are single-planet systems, while others are multiple-planet systems. Each organization can submit one naming proposal, for one ExoWorld only. The number of names that need to be submitted depends on which system is selected. For single- and multiple-planet systems, a name for each planet must be submitted, as well as one for the host star. In the 20 ExoWorlds list, five stars already have common names. Consequently, these five stars cannot be considered for public naming.

View larger. | 20 nameable exoplanets, via IAU

To participate in the contest, clubs and non-profit organisations must first register with the IAU Directory of World Astronomy. The deadline for registrations has been extended to 23:59 UTC on 1 June 2015.

All naming submissions having to abide by the IAU Exoplanet naming conventions and must be supported by a detailed argument for their choice. The deadline for submitting naming proposals is 23:59 UTC on June 15, 2015.

Once this stage has concluded, the public worldwide will be invited to vote on their favorite proposed names.

The final results are expected to be announced at a special public ceremony held during the IAU XXIX General Assembly in Honolulu, August 3–14 , 2015.

Bottom line: Registered clubs and organizations may enter proposals in the IAU and Zooniverse NameExoWorlds contest. Deadline June 15, 2015. Fifteen stars and 32 planets (47 objects total) in 20 solar systems available for naming. Register your club or organization here.

Comets explained for everyone. Facts, Types, and Parts.

Comets are cosmic objects made of rock, ice, dust, and frozen gases. Comets travel around the Sun just like planets do, but unlike planets, they have long, elliptical orbits that take them very close to the Sun.

Comets look interesting to us because of how they look. They seem to leave a long trail of light behind them while they travel. Thanks to this, they can become spectacular shows to watch even when they are relatively small objects compared to other objects in the sky. Comets have a diameter of only a few kilometers and era as big as a small town.

The tail in comets is created when they go near the Sun. The Sun’s light interacts with the ice and gases concentrated in the comet creating an atmosphere around it. The light scattered by this process gives comets their luminous look. Some pieces of dust, ice, and gases in the comet get vaporized and are launched in a stream away from the body of the comet, creating the tail that we see behind them.

When comets are far away from the Sun they are hard to detect as they don’t have a tail, don’t reflect enough light and are too small.

The word comet comes from the Latin word comēta which means “To wear long hair” in reference to the comet’s tail that looks a little bit like strands of hair.

Parts of a comet

Comets are some of the simplest cosmic objects to understand. They are composed only of three main parts that we will explain in detail below.

Parts of a comet

Nucleus – A comet’s nucleus is the solid core of it. It the the rocky, icy part.

Coma – The coma is the thin atmosphere formed around the nucleus. It is created by the gases that are expelled from the core. While the visible part of it is only a bit bigger than the nucleus, the coma can actually extend for thousands of kilometers.

Tail – The tail is the most visually impressive part of the comet. It is the stream of dust and gas that is left behind the comet as it travels and reacts to the Sun’s radiation. The comet’s tail always points away from the Sun.

How big are comets?

Comets vary in size and it is hard to tell exactly how big one is as they tend to have irregular shapes, unlike planets that are mostly circular. The second problem is small comets might become too hard for us to detect.

Usually, smaller comets are between 2 and 15 kilometers (1.8 to 9.3 miles) in diameter, but that is only the main body (nucleus). The tail itself can be as long as 150 million kilometers long (93 million miles). An easier way to remember this is to say comet’s size can be between a football stadium with the parking lot and smaller than Manhattan. The tail can be as long as the distance from Earth to the Sun (which we call 1 Astronomical unit).

How many comets are there?

With our current data, 6,339 comets have been detected and classified, but new comets are being constantly launched and formed.

Where do comets come from?

Illustration depicting the location of the Kuiper Belt and the Oort Cloud

Before we get into where do comets come from we need to explain a couple of groups in our Solar System.

The Kuiper Belt – Also called the Edgeworth–Kuiper belt, it is a ring of rocks made of ice and metal and asteroids just like the asteroid belt, except that The Kuiper Belt is located beyond Neptune and is estimated to be 20 to 200 times larger than the asteroid belt.

The Oort Cloud – Also called the Öpik–Oort cloud, it is a huge cloud of really small icy objects in the outer skirts of the Solar System. The Oort Cloud is estimated to contain billions or even trillions of objects, but it is so far away and the objects are so small that it is hard to get an accurate estimate.

With those terms cleared, now we can get into the two classifications for comets based on how long it takes them to complete their orbit. Short period comets and long-period comets. Short period comets have an orbit of fewer than 200 years while long-period comets take more than 200 years.

It is estimated the short period comets are formed and come from the Kuiper Belt while long-period comets come from the Oort Cloud.

How are comets created?

Comet 67P/Churyumov–Gerasimenko

Like many objects in the Solar System, comets are formed from the collision of smaller objects that are attracted to each other thanks to gravity and the randomness of their trajectories.

As mentioned in the section above, comets in the Solar System are formed in the Oort Cloud or the Kuiper Belt where there are trillions of small icy and metallic objects. When these objects clash with one other they form bigger and bigger rocks. Every once in a while, one of these impacts will be powerful enough to impulse one object out of its original orbit and sends it around the Sun in a brand new one.

Types of comets

Comets are so irregular and different one another that classifying them is a difficult task. This has created many categories and classifications for comets that might make things confusing.

For practical purposes, let’s stick to the five main categories of comets.

  • Periodic Comets. Also, know as short period comets, have an orbital period of fewer than 200 years. Most periodic comets are hypothesized to be formed in the Kuiper belt. Halley’s comet is a periodic comet with an orbit of 75.3 years.
  • Non-periodic comets. Often referred to as long period comets, they have an orbital period longer than 200 years. The Hale–Bopp comet which was visible from Earth with the naked eye for more than 18 months in 1997 is a non-periodic comet. It is believed most of these comets are originated in the Oort Cloud.
  • Hyperbolic comets. These are comets with no meaningful orbit. Most of these comets will only orbit the Sun once and then are slingshotted by the Sun’s gravity outside the Solar System. It is believed some of these comets might even be interstellar, meaning they have traveled from other systems.
  • Lost comets. These are comets that for some reason or another have been “lost” after their discovery, meaning their fate is unknown.

In 2017 a new letter was added to the international naming convention for comets to separate interstellar comets from the other types, however, the can still be classified as non-periodic or hyperbolic comets.

The complete list of comet types, their sub-types and a list of comets of each type can be found here.

How are comets named?

Some important comets like the Halley and the Hale-Bopp comets are named after the astronomers who discovered them. Naming all of them like this would be difficult and confusing so astronomers have come up with a naming convention.

Comet names mostly look something like D/1977 C1, C/2002 U6 or 1P/-239 K1

The current naming convention has three parts.

The first letter indicates the type of the comet using the following rules:

  • P – Periodic comets
  • C – Non-periodic comets
  • D – Hyperbolic comets
  • X – Lost comets
  • A – Objects that were mistakenly classified as comets. Only 3 objects have received this classification.
  • I – Interstellar comets

The second part of the name is the year the comet was discovered. In some cases, for comets that were discovered a long time ago, a sign is added to denote the year of discovery is estimated.

The third part of the name is a prefix assigned after the second observed passage of the comet.

The Fate of Comets

Hale-Bopp comet seen from Earth on 1997

New comets are constantly being created but a lot of them also disappear in one of three different ways.

Fading. You could call this the natural death equivalent of comets. It happens after all the gas and ice in the comet’s nucleus is exhausted after passing close to the Sun many times. Once that happens, all that remains is rock and metals and the comet could now be classified as an asteroid. Short-period comets can survive up to 1,000 orbits around the Sun while most long-period comets fade before completing 50 orbits.

Collisions. Sometimes a comet’s orbit will coincide with a bigger object and crash into it or if it’s a planet with an atmosphere, it can also burn out. Jupiter is famous for having received many comet impacts in the past.

Ejection from the Solar System. If the comet is fast enough, it can be slingshotted when it passes close to a big object like Jupiter or the Sun thanks to their gravity. This sometimes has the effect of ejecting the comet outside the Solar System.

Comets and Meteor Showers

One very cool fact you can learn about comets that most people don’t know is comets are the cause of meteor showers.

Meteor showers are a stream of meteors burning in Earth’s atmosphere at a fast rate during a short period of time. They make for a great light show and are some of the events even people who are not into astronomy enjoy watching.

As comets travel through their orbits, they leave dust and small pieces of rock and ice that split from it. These rocks float in space for a long time. When Earth’s orbit passes through one of these areas, they enter the atmosphere due to Earth’s velocity and gravity. At this point, they burn out in the atmosphere and can now be considered meteors.

Halley’s comet even causes 2 separate meteor showers. The Eta Aquariid meteor shower in May and the Orionids which occurs around October every year.

Are there comets in other solar systems?

Yes. They are called exocomets. Astronomers believe comets are relatively common phenomena, at least in our galaxy, the Milky Way. Ten systems with exocomets have been identified so far but more are being constantly discovered.

Is it possible to see a comet with the naked eye?

Yes, however only one comet can be seen every year on average and they are mostly too small to be an interesting view. Only big, bright comets like the Hale-Bopp comet of 1997 are bright enough to present a show in the night sky.

With the help of a telescope, however, comets can be really fun to watch. If you want to give that a shot, here’s a constantly updated list of comets that can be seen from Earth.

Elena is a Canadian journalist and researcher. She has been looking at the sky for years and hopes to introduce more people to the wonderful hobby that is astronomy.

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About Little Astronomy

Hi! I’m Elena. I’m a journalist who has been into astronomy since I was a kid. I founded this site to share tips and facts about astronomy and telescopes.

If you are new around here and you want to get started with the hobby, take a look at our recommended gear page.

This section describes the components of file naming for observed sources (including standard stars).


The file type is indicated by its prefix, a short label. The following Table lists all formats for the Outputs of PypeIt. We describe each and include the likely suffix(es).

multi-extension FITS one binary FITS table per extracted object

multi-extension FITS one 2D array per spectral image

Series of figures assessing data reduction and data quality


The second label indicates the instrument. Here are the set of currently supported instruments in PypeIt:

blue camera of the Kast dual-spectrometer

red camera of the Kast dual-spectrometer

blue camera of the LRIS spectrometer

Date and Time¶

By including the UT observing date and time to the nearest second, we believe the filename is now unique. The UT date + time are drawn from the Header and refer to the start of the observation, if there are multiple time stamps. Other DRPs (e.g. LowRedux) have tended to use the Frame number as the unique identifier. We have broken with that tradition: (1) to better follow archival naming conventions (2) because of concerns that some facilities may not include the frame number in the header (3) some users may intentionally or accidentally generate multiple raw files with the same frame number.

A typical filename may then appear as:

Source Identifiers¶

PypeIt reduces each detector separately and associates identified slits and objects to that detector. Therefore, sources are uniquely identified by a combination of these source-id-values (out of date!). If requested, the Spec1D files can be exploded to yield one FITS file per source. In this case, the filenames are appended by the source identifiers:

A complete filename may then appear as:

For sanity sake, files that are exploded in this manner are placed into their own folders named by the instrument and timestamp.

It is very common in Star Trek, but it exitsted in earlier science fiction novels and short stories. What is the earliest occurrence of this naming scheme? When was it first described? When was it first implied?

The naming convention has been in common usage forever in science fiction. E.E. Smith from the first Galactic Patrol serial in 1937 referred to planets such as Velantia III, Rigel IV, and Palain VII, and Earth was specifically referred to as Sol Three from time to time in the series.

The following examples are from Galactic Patrol:

"For instance, Kinnison here once had a highly adventurous interview with a lady of Aldebaran II and her friends."

Astounding, September 1937, page 11

"Kimball Kinnison of Sol Three calling Mentor of Arisia. Is it permitted that I approach your planet?"

"Kinnison of Tellus, greetings. Tregonsee of Rigel IV calling from Trenco space-port. Have you ever landed on this planet before?"

"Lensman of Trenco Space-port--Tregonsee or his relief? Lensman Kinnison of Sol III asking permission to land."

". the fifth dove into the deepest ocean of Corvina II, in the depths of which all rays are useless."

Out from Radelix and into deep space shot the speedster, bearing the Gray Lensman toward Boyssia II, where the Boskonian base was situated.

"He was Lageston of Mercator V--a good man, too. What is your pressure now?"

One should note that at no point does Smith explain that "Sol III" means "third planet from the star Sol" or Aldebaran II means "second planet from the star Aldebaran". This implies one of two things: either Smith used it for the very first time and expected the readers to figure out what it meant without explanation--which given Smith's writing style would seem to be unlikely since he tends to explain everything--or the style of naming planets in that way was already in science fiction at the time so as not to require explanation.

This is a naming scheme that has been used for moons since they were discovered. For example, since their discovery all the way to the 20th century, Jupiter's moons were known simply as Jupiter I, Jupiter II, Jupiter III and Jupiter IV. As new moons were discovered, this practice was followed. Even for the four most easily observable moons of Jupiter, the naming scheme surived for about three hundred years many of the others only got their name in 1970s or later.

Remember that before heliocentric (or geocentric) models came to a good description of the solar system, people didn't even know that planets had an ordering. They were simply "wanderers" - stars that moved in relation to the "fixed" stars, and in predictable (though sometimes complicated) patterns. So they were named long before the ordering was discovered, and they were often given divine qualities (which still survive today in e.g. Astrology). If planets were somehow only discovered in the 17th century, like the moons of Jupiter, it's quite possible we would have simply called them Sol I, II, III.

The main problem with this is that the ordering can change - or rather, we might discover a orbiting body between two previously discovered bodies. There are some workarounds around this, but either it means you need to change the names of already discovered satellites, or you preserve the order of discovery rather than the orbital order.

The formal naming scheme came from IAU in 1975. Since then, newly discovered satellites of Jupiter are supposed to be named after the lovers and favourites of Jupiter/Zeus. A 2004 definition expanded this to their descendants. Since the names no longer have any implicit ordering, you avoid the confusion of whether Jupiter III is the third moon, or the third moon that has been discovered, or the third largest moon, or having to name the moon between Jupiter III and IV something like Jupiter IIIb.

If you're exploring the universe fast with your flashy new FTL drive, it makes sense to use placeholder names. A numbering scheme would work until you have a better name, which would usually follow an actual colonisation or mining operation. In much sci-fi, planets are known under multiple names - some are official designations, some are local names, others are well-known nicknames. So a planet known as Rigel IV might also be known as "Jerryworld" to its inhabitants, but they would still use the "official" name when communicating with outsiders. At least if you preserve the numbering to mean order, it's easier to maintain interstellar maps - presumably, in such advanced interstellar civilizations, the ordering would only change due to astronomical cataclysms, which are far rarer than human naming :) If you never heard of Earth, which helps you find it in your star map - the name "Earth", or "Sol III"?

As for the somewhat popular names like Terra or Luna, I expect they're meant to symbolise how small one planet is in the galaxy, much less the universe. Latin has long been used as the international language of science (even in medieval times), so it's not really a poor choice of one name all of Earth could agree on. Having 200 widely used names for one planet might be rather inconvenient for a galactic civilization.

The Power of Good IT Security Naming Standards

When I first started in information technology, one of the more humorous aspects was the naming convention customers chose for servers. For example, one customer chose starship names from Star Trek, and another customer picked characters from Disney movies. While silly, it was easy to remember that “Enterprise” was a file and print server, and “Hercules” was a Domain Controller.

Unfortunately, as we began adding dozens, hundreds, and thousands of systems we ran out of names, and figuring out that DS9 was a web server became less intuitive. In addition, I remember one customer actually being served a legal notice to stop using trademarked names within their organization to designate assets. That was a disaster in itself because, as a consultant, we needed to rename everything – including taking systems off the domain. This entailed renaming them, fixing broken applications (like MS SQL at the time), and rejoining them to the domain. This was completely separate from all the entitlement and permission problems. As a result, the customer had to adopt a new naming standard for host names and user accounts.

Today, as information technology has evolved, naming standards are critical and impact everything from unique traits in applications to cloud resources and DevOps. Picking a good naming convention that has longevity for future growth is a crucial first step in any deployment and initial design. Getting it right can be the difference between having a sustainable deployment or a management nightmare.

For a privileged access management (PAM) deployment, there is a need to honor the nomenclature chosen for hostnames and credentials. This includes DNS references and differentiators in credentials that designate administrators, standard users, service accounts, and application to application (A2A) accounts. If these are standardized, and not random names (Spock, Wreck_it_Ralph, or Voyager), rules for automated management, onboarding, and account identification are relatively straightforward. For example, all administrator accounts are designated with a “admin-“prefix or all web servers contain “*web*” in their hostnames and DNS entries.

For a successful BeyondTrust PAM deployment, however, there are up to eight additional new traits that will need a standardized nomenclature developed. These include:

  1. Workernode Name – The agent name assigned to a distributed worker node. This is inherited from asset host name and may require its own nomenclature schema per location and per serviced client.
  2. Workgroup Name – The unique ownership classification assigned to assets and users to distinguish collision domains. For a single organization, there is typically only one workgroup name, but if multiple worker nodes are implemented or a multitenant deployment is configured, multiple workgroup names will be required.
  3. Organization Name – A collection of workgroup names to designate an organization. This is only designated in a multitenant implementation and organization names may be obfuscated to account numbers or other designations to protect the managed identities.
  4. Policy Name – The name designated to any privileged policy for context and application access by asset (computer) or user (account).
  5. Smart Group Name – The name logically grouping assets or accounts within BeyondInsight, BeyondTrust’s centralized console. This name is visible to end users with the proper permissions and provides role-based access and reporting capabilities by group.
  6. Smart Rule Name – The name assigned to an automated rule. Smart Rules can drive automated actions or logical groups (Smart Groups) and be designated for assets, accounts, or vulnerabilities within the solution.Functional Account Name (Alias) – The privileged account on a platform used for management of other accounts, including password rotation. Typically, these are domain accounts, but may exist locally per platform for the management of end user accounts.
  7. Scanner Agent Name – The reference name displayed in BeyondInsight for a Retina Network Security Scanner or Retina Host agent. The name is manually set (like the workgroup) and does not need to equal the hostname.

From a solution best-practice perspective, keeping this in line with existing standards just makes sense. For example, Workgroup names may be geolocation, VLANs, or ownership-based and may look like “New York Workgroup”, “DMZ X1”, or “Boca Raton Development Lab”, and Functional accounts may look like “WinFunctional-Corp.Domain” or “Linux-PCI-Functional”.

A good nomenclature standard specifies any prefix, suffix, and content by word for the naming convention. This can include granularity down to the number of characters and potential combinations of the characters, like the first three letters designating the operating system or the containing solution owner information in a rule or group name.

While we consider what a successful privileged access management deployment may look like in your environment, it is important to consider what policies and procedures may need to be enhanced to deploy a sustainable solution. Having standard nomenclature for the unique traits of privilege management will certainly help to streamline the implementation and management beyond your initial deployment.

For assistance in planning your privilege management deployment, contact us today for a strategy session.

Morey J. Haber, Chief Technology Officer and Chief Information Security Officer at BeyondTrust

Morey J. Haber is Chief Technology Officer and Chief Information Security Officer at BeyondTrust. He has more than 25 years of IT industry experience and has authored four Apress books: Privileged Attack Vectors (2 Editions), Asset Attack Vectors, and Identity Attack Vectors. In 2018, Bomgar acquired BeyondTrust and retained the BeyondTrust name. He originally joined BeyondTrust in 2012 as a part of the eEye Digital Security acquisition. Morey currently oversees BeyondTrust strategy for privileged access management and remote access solutions. In 2004, he joined eEye as Director of Security Engineering and was responsible for strategic business discussions and vulnerability management architectures in Fortune 500 clients. Prior to eEye, he was Development Manager for Computer Associates, Inc. (CA), responsible for new product beta cycles and named customer accounts. He began his career as Reliability and Maintainability Engineer for a government contractor building flight and training simulators. He earned a Bachelor of Science degree in Electrical Engineering from the State University of New York at Stony Brook.

Loading and Shaping Data

Push Shaping as Close to the Source as Possible

  • Wherever possible, you should do your data shaping as close as possible to the data source.

There are many ways that you can shape your data in Power BI. Power Query is a great tool to reshape your data however you can also use DAX (Calculated Columns, Filters on load) and Power BI also includes Calculated Tables. And you can always write SQL code and paste that into the tools to extract the data that way. The main problem with these approaches is you are effectively hard coding a solution for a single data set. If you want to build another data set in the future, the work needs to be done again (either copy or re-write). The data shaping tools are designed to allow you to do whatever you need without having to rely on a third party – use these tools if you need to. However if you have a common need for data in a particular shape and you can get support (from IT or otherwise) to shape your data at the source so you can easily get what you need, then there is definitely value in doing that.

Shape with ‘M’ in Power Query, Model with DAX in Power BI

Power Query (‘M’) and DAX were built to do 2 completely different tasks. Power Query is built for cleansing and shaping while DAX is built for modelling and reporting. It is possible that you can shape your data with DAX (e.g. you can write calculated columns, you can add calculated tables, etc.). But just because you can do these things with DAX, doesn’t mean you should. For example it is possible to write letters to people using Excel, but Word is a much better tool for this task (I knew someone that once did that!).

Best practice is that you should use Power Query to shape your data before/during load, and then use DAX for measures and reporting. I have deeper coverage on this topic here.

Use A Calendar Table

It is possible that you can analyse your data in a single flat table without using any lookup/dimension tables. A Calendar table is a special type of lookup/dimension table because it can be used in the time intelligence functions. I have an article on time intelligence here and another on Calendar tables here. Bottom line – get a Calendar table.

A Star Schema is Optimal

I have an in-depth article about star schemas here that you can read if need be. I am not saying this is the only layout that will work, or that other designs will always be slow. I am saying that if you start out thinking about a star schema and aim to build that design you will be well under way to success. Two key things you should know.

  • Don’t just bring in what is in your source transactional database – that would likely put you into a world of pain.
  • There is no need to create a lookup/dimension table just for the sake of it. If your sales table has customer name and you don’t care about anything else about the customer (e.g. city, state etc.), then there is no need to create a lookup table just for the sake of creating a star schema. If you have 2 or more columns relating to the same object in your data table, then it is time to consider a lookup table.

You Should Prefer Long and Narrow Tables

  • Short wide tables are generally bad for Power BI but long narrow tables are great.

There are 2 main reasons why loading data this way is a good idea.

  • Power BI has a column store database. It uses advanced compression techniques to store the data efficiently so it takes up less space and so it is fast to access the data when needed. Simplistically speaking, long narrow tables compress better than short wide tables.
  • Power BI is designed to quickly and easily filter your data. It is much easier/better to write one formula to add up a single column and then filter on an attribute column (such as month name in the green table above) than it is to write many different measures to add up each column separately.

Only Load the Data You Need

If you have data (particularly in extra columns) you don’t need loaded, then don’t load it. Loading data you don’t need will make your workbooks bigger and slower than they need to be. In the old world of Excel we all used to ask IT to “give me everything” because it was too hard to go back and add the missing columns of data later. This is no longer the case – it is very easy to change your data load query to add in a column you are missing. So bring in all of what you need and nothing you don’t. If you need something else later, then go and get it later. Focus mainly on your large data tables – the lookup/dimension tables tend to be smaller and hence are generally less of an issue (not always).

If you want a comprehensive lesson on how to use Power Query, checkout my Power Query Online Training course here.

Why Mathematicians Should Stop Naming Things After Each Other

A ny student of modern math must know what it feels like to drown in a well of telescoping terminology.

For a high-profile example, let’s take the Calabi-Yau manifold, made famous by string theory.

A Calabi-Yau manifold is a compact, complex Kähler manifold with a trivial first Chern class.

Before you could even guess what that definition might mean, you would need to find another source to define a Kähler manifold:

A Kähler manifold is a Hermitian manifold for which the Hermitian form is closed.

After which you would need a third source to define a Hermitian manifold:

A Hermitian manifold is the complex analogue of the Riemannian manifold …

And you’re down the rabbit hole. When everything is named for its discoverer, it can be impossible even to track the outline of a debate without months of rote memorization. The discoverer’s name doesn’t tell you anything about what the landscape is like, any more than the “Ackerman” in Ackerman’s Island helps to convey a sandbar in downtown Wichita. Except in a few one-hit-wonder situations where a famous mathematician had extremely narrow tastes (like an Ackerman who, as everyone knew, could only live on sandy substrates, and never left the state of Kansas), their name gives no mnemonic boost whatsoever. Whatever faint associations it might once have held fade away, especially when the discover was neither famous nor narrow, and the reader is several generations removed.

Some very nice names have sprung up with no clear first use, like “pair of pants” and the Hairy Ball Theorem.

This nesting of proper nouns helps to make higher math impenetrable not just to outsiders, but also to working mathematicians trying to read their way from one subfield into another. The venerable Bill Thurston was known to complain about the perversity which, by the end of his career, had produced Thurston’s theorem, which says that Thurston maps are Thurston-equivalent to polynomials, unless they have Thurston obstructions. Every field has terms of art, but when those terms are descriptive, they are easier to memorize. Imagine how much steeper the learning curve would be in medicine or law if they used the same naming conventions, with the same number of layers to peel back:

A Thurston tumor is a benign Thurston growth in the bones of patients with type-1 Thurstonism.

A Thurston homicide requires a finding of Thurston recklessness and is a Thurston-class felony.

The Ancient Greeks were better about this. Euclid’s Elements is full of common, descriptive names, even though he was drawing on discoveries made by many different people. If he needs a term for something like a triangle with two sides of the same length, he calls it “isosceles,” literally “equal-legged” in Greek. A triangle with sides of all different lengths is “scalene,” or “unequal.” Euclid doesn’t even name the Pythagorean Theorem we all learn in school after Pythagoras, preferring just to state it plainly. In ancient Greece, it was polite for students to attribute their work to their teachers rather than themselves, if attribution was needed at all, so in the same way that Plato credited his own insights to Socrates, the eight or more objects now named after Pythagoras on Wolfram MathWorld might well be due to his students.

Things seem to have gotten out of hand after the Renaissance. Pierre Fermat’s name is on not just his Last Theorem and his Little Theorem, but on points, primes, pseudoprimes, polynomials, conics, spirals, a principle in optics, and a method for factoring odd numbers. Henri Poincaré, working at the end of the 19th century, has at least 21 mathematical entities named after him. It looks to me as though Bernhard Riemann might have as many as 82.

The average number of coauthors on math papers has gone up since 1900. So has the number of working mathematicians in the world, which raises the odds of independent rediscoveries, separated in time or space. These two trends have opened the door to triple and even quadruple hyphen situations, as in the Albert-Brauer-Hasse-Noether Theorem and the Grothendieck-Hirzebruch-Riemann-Roch Theorem.

Imagine how much steeper the learning curve would be in medicine if it used the same naming conventions.

Names may get even longer if Vladimir Voevodsky carries the day and modern math becomes dependent on computer-verified proofs. Papers published through big collaborations on shared technologies in other fields now have thousands of authors, but a theorem cannot have a thousand hyphens. We could pack in more people if we used initials, as with HOMFLY polynomials, named for their six co-discovers (Hoste, Ocneanu, Millet, Freyd, Lickorish, and Yetter) and sometimes even called HOMFLYPT polynomials, to mete out credit to Przytycki and Traczyk as well.

That, or mathematicians could take a pass on immortality and introduce their new objects with sensible, semantically parsable names instead.

For role models in the modern age, we look first to John Horton Conway, lately lost to COVID-19, whose many amazing names include the Monster for the largest sporadic simple group (with over a thousand octillion elements) as well as Monstrous Moonshine for that group’s totally unexpected connection with modular functions. More recently in topology, I have enjoyed Josh Greene’s changemaker vectors, whose components can sum to any integer less than their total value, as if making exact change with cash. David Wolpert and Bill Macready proved the No Free Lunch Theorems often cited in machine learning, which hold that every improvement in an optimization algorithm in one domain must come at the expense of worse performance in another, although Wolpert attributes their name choice to David Haussler. Surely we can agree it is a much better name than “Wolpert-Macready-Haussler Theorems” would have been.

Of course, some credit or blame must lie with the collective response to a new result, not just the individual who presents it. Poor Riemann did not name Riemannian manifolds after himself. Names like that emerge in the wave of secondary scholarship reacting to a new idea, and emergent names aren’t always bad. Some very nice names have sprung up though diffuse consensus with no clear first use, like the term “pair of pants” for a sphere with three holes in it (which I can’t trace further than a Bourbaki Seminar in 1978) and the Hairy Ball Theorem, which says that every vector field on a sphere with even dimensions must have a zero point, so any hairy billiard ball must have a cowlick (whose trail runs cold with Morris Hirsch’s Differential Topology textbook in 1976). But in general, mathematicians seem to feel a Scout’s Honor to name new things after their creators, unless those creators act like Conway and make concerted, repeated efforts to give descriptive names to their own objects instead.

The Deepest Uncertainty

Georg Cantor died in 1918 in a sanatorium in Halle, Germany. A pre-eminent mathematician, he had laid the foundation for the theory of infinite numbers in the 1870s. At the time, his ideas received hostile opposition from prominent mathematicians in Europe, chief among them. READ MORE

In the last decade, the field of algebraic geometry was set on fire by “perfectoid spaces” rather than “Scholze spaces” because Peter Scholze kept on calling them that in his talks and papers. Like Conway and Wolpert, he put his descriptive name into the titles of his work, not just the body. That seems to help. By contrast, Shing-Tung Yau says in his autobiography that the Calabi-Yau manifold was given its name by other people eight years after he proved its existence, which Eugenio Calabi had conjectured some 20 years before that. Calabi and Yau would have had more right than anyone to interject and suggest something else, but as Yau tells it, they were both proud and happy to watch their names spread together through scholarly publications and through popular culture. What we have now is a system which gives naming rights to the discoverers in an implicit way, where your contributions will bear your names by default, unless you decide to agitate for something else.

Why do mathematicians continue to proffer and accept this courtesy, when it increases their own mental load and makes their own work more opaque?

The worst answer I can imagine is the one Pope Gregory VII gave for refusing to let the Holy Scripture be translated out of Latin: “. [I]f it were plainly apparent to all men, perchance it would be little esteemed and be subject to disrespect or it might be falsely understood by those of mediocre learning, and lead to error.” The memory-intensive naming schemes in modern math may have the result of boxing out the laymen, but we must hope the priests of the academy are not doing it on purpose.

A more sympathetic answer would be that mathematicians want the glory of seeing their names outlive themselves as a reward for the long, solitary hours they labor to produce their results. In law or in medicine, research has a practical object, often with money attached. Can we count on the pleasure of finding things out to sustain work in pure math, if we eliminate this appeal to the ego?

I hold out the hope that research culture would be better off without it. One of the most compelling reasons Grisha Perelman gave for refusing his Fields Medal and his Millennium Prize was the unfairness of singling out one person as the progenitor of a 100-page proof, which necessarily represents a stitching together of many people’s breakthroughs, made over many decades of work. Changing the name scheme of modern math might imply a change in motive force, but if that change discouraged some people, it might welcome others in.

Laura Ball is a journalist-in-residence at the Kavli Institute for Theoretical Physics, a Thiel Fellow, and an alumna of the Math Prize for Girls program. She spent the last two years researching computational morality at Mila, the Quebec AI Institute.

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