The Nearest stars - 40 Light Years
Source
This model is generated from data obtained from the 'Preliminary Version of the 3rd Catalogue of Nearby Stars', Gliese W. and Jahreiss H. (Astron. Rechen-Institut, Heidelberg, 1991). The catalogue is listed at NASA's Astronomical Data Center as 5070a.
The data includes over 3800 stars with a trigonometric parallax >= 0.0390 arcsec (25 Parsecs). Test models I did to 50 LY (1061 stars) were too large and unwieldy, so I've limited this model to a distance of 40 light years (561 stars).
Names
Only the stars visible from Earth have been named (visual magnitude < 6). With all names showing, the stars themselves are hidden in the clutter.
The names of the stars were obtained from the following fields:
- Remarks (if a Bayer Letter/Constellation) *
- Giclas
- LHS
- OtherName
- Ident
*
A) Extraction of the Bayer letter and constellation from the
remarks field proved tricky as the field contains a variety
of other information in no fixed order. I searched each Remark
for Greek letters then extracted the letter, suffix (e.g. (2)) and
3 letter constellation name.
It will fail if it encounters a
(hypothetical) name such as OMI(10) Sig, as it assumes that the
digit only goes up to 9. In this case the extraction code
would return 'OMI(10) Si', omitting the last character.
In addition, the code does no 'back check' that would enable it to
detect the '50' in '50 UPS And'. This will return 'UPS And'.
B) I browsed the data file to check the abbreviations it used for
Greek letters, it listed every letter except Omega. I check for
'OME' irregardless.
Stars
Color
Although the spectral class is listed in the data file, I've ignored it (it had even more variants than the Bayer/constellation) and instead used the absolute magnitude as a rough guide to the star's color.
- minimum mag RED to 4.79 (Sol's mag) YELLOW
- 4.79 to 3.79 WHITE
- 3.79 to maximum mag LIGHT BLUE
Multiples
Binary and Tertiary star systems are shown by placing the B and C stars further from Sol by 0.2 and 0.4 ly respectively. This leads to the peculiar situation that Rigil Kentaurus (Alpha Centauri A) appears closer to Proxima Centauri (about 0.19 ly), than it's own orbital star, Alpha Centauri B. Oh well, ya' get that..
Position
Celestial coordinates are given according to epoch 1950. Since the data file contains the star's velocity through space, I'm considering including this by animating the stars over time. Unfortunately the models are already approaching the upper limit of what can be presented using LiveGraphics3D (the Java engine that generates the model), so this may have to wait until I become proficient with Java and can write my own code (don't hold your breath..).
Notes
Spinning the model after the names have been removed reveals several significant 'voids' where there are no stars for 3-5 ly wide by 6-10 ly high through the entire 40 ly of the model. I would like to refine the code to highlight these areas, but so far I have no inspirations on how to detect them mathematically.
It might also be interesting to show a projected 'mass density' of the system, as a single bright star may account for the mass of 100's of dim stars. Again though, my knowledge of astrophysics is not comprehensive enough to know how to do this.
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