Saturday, August 14, 2010

Designations for Nearby Stars

Last time I wrote about my update to the NSTARS database (the original of which seems to have gone to internet heaven). But now I want to talk about how we designate near stars.

The NSTARS database used a notation popularised by the CCDM and WDS double-star databases, in which the position in the sky is truncated and converted to a code. For example, the star Arcturus which is located at ra=14 15 39.7, dec=+19 10 56.7, has an original NSTARS designation NS 1415+1910. Scientists like it because of its precision and (mostly) self-ordering properties, but for a topic like near stars, which you expect will get much public attention, it is terrible for communication. Can you imagine an article written about the discovery of an otherwise unnamed near star, having to repeat the mouthful over and over?

We have simple ways of referring to bright stars (Alpha Centauri), variable stars (CN Leo or V645 Centauri), but no uniform designations for nearby stars, even though the availability of accurate parallaxes now means that we're in a better position than ever to accurately determine just how near a star is.

My proposal is simple. See the variable designation I used above? Let's swap N for V, and gloss over all the subtleties involved with that system (e.g. inclusion of Bayer designations, R..QZ letters). Order the current catalogue in order of increasing distance from the Sun, keeping multiple systems together (this is only for initial designations). We then follow these simple steps:
  1. Our own Sun gets the special designation, N0;
  2. The other stars are ordered N1, N2 etc., followed (& grouped) by their Constellation, in the same way as bright and variable stars are. So the next system, Alpha Centauri, becomes N1 Centauri (Proxima Centauri is N1 Centauri C);
  3. Designations are assigned down the list. Barnard's Star is N1 Oph  for short, 2MASS J10481463-3956062 is N1 Ant (better, yes?). LHS 337, the next closest star in Centaurus, becomes N2 Cen;
  4. Once assigned, designations are never modified if new parallaxes become available. The sorting is only for a convenient initial list. If a new near star in Cygnus is discovered, the next available designation is given (N41 Cygni), regardless of distance.
What do you think? I'm hoping that this system will be adopted, and a suitable body take over the maintenance of the list. As things stand, no universal system exists (we use PLX, LHS, GJ, 2MASS etc as needed), save for the NS system, which is apparently defunct, not widely used, and in my opinion, cumbersome.

No comments:

Post a Comment