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The Question
(Submitted June 09, 1998)
I'm doing a research paper on solar type stars within 50 light years of
the sun. Can you give me a reference on the web?
The Answer
The astronomy frequently-asked-questions (FAQ) list
http://sciastro.astronomy.net/says:
Subject: G.05 Where can I get stellar data (especially distances)?
Author: Steve Willner
The Strasbourg Astronomical Data Center maintains a large inventory of
astronomical catalogs, including star catalogs. Access at
http://cdsweb.u-strasbg.fr/.
The HIPPARCOS catalog,
http://astro.estec.esa.nl/Hipparcos/, represents a gigantic
improvement both in systematic accuracy and in precision over previous
catalogs, but it is limited to fairly bright stars (magnitude limit
around 11). Keep in mind that all astronomical data have
uncertainties. Distances can be especially problematic, and it is
vital to know what the uncertainties are.
One large (3803 stars) compilation of nearby stars can be found at
http://vizier.u-strasbg.fr/viz-bin/ftp-index?V/70A.
An excerpt from the "ReadMe" file,
http://cdsweb.u-strasbg.fr/viz-bin/Cat?V/70A follows:
Preliminary Version of the Third Catalogue of Nearby Stars
GLIESE W., JAHREISS H.
(Astron. Rechen-Institut, Heidelberg (1991))
Description:
The present version of the CNS3 contains all known stars within
25 parsecs of the Sun. It depends mainly on a preliminary version
(Spring 1989) of the new General Catalogue of Trigonometric
Parallaxes (YPC) prepared by Dr. William F. van Altena (Yale
University).
The catalogue contains every star with trigonometric parallax
greater than or equal to 0.0390 arcsec, even though it may be
evident from photometry or for other reasons that the star has a
larger distance. For red dwarf stars, new color-magnitude
calibrations for broad-band colors were carried out and applied.
For white dwarfs, the recipes of McCook and Sion in ApJS, 65, 603
(1987) were applied. Stroemgren photometry was used (not yet
systematically) for early-type stars and for late dwarfs, the
latter supplied by E. H. Olsen from Copenhagen Observatory
(private communication).
Contrary to the CNS2 (Gliese 1969) trigonometric parallaxes
and photometric or spectroscopic parallaxes were not combined.
The resulting parallax in the present version is always the
trigonometric parallax---if the relative error of the
trigonometric parallax is smaller than 14 percent. The resulting
parallax is the photometric or spectroscopic parallax only if no
trigonometric parallax is available or if the standard error of
the trigonometric parallax is considerably larger.
If you'd like to use the astronomical data, say, to calculate
distances between stars, a useful reference is
http://www.projectrho.com/starmap.html.
Since the catalog was compiled (1991) the Hipparcos mission has provided
better distances to these stars. However, this catalog will probably be
sufficient for your needs.
David Palmer
for Ask a High-Energy Astronomer
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