The Catalogue of Nearby Habitable Stars (known as HabCat) is a list of star systems that could conceivably host habitable planets. Developed by Margaret Turnbull and Jill Tarter, the HabCat list was created by taking data from the Hipparcos Catalogue (which contains approximately 120,000 nearby stars) and eliminating those stars that have no possibility* of hosting a habitable planet, bringing the number of possible "HabStars" down to 17,129.
Please note that while they have removed those stars incapable of hosting a habitable planet, "HabStars" are not guaranteed to have such a planet, or be populated by life in any form.
HabStars are color-coded by distance. The order from closest to farthest is red, pink, yellow, white, green, light blue, dark blue, and purple. The colors are determined by a log scale.
Give the Google Sky Gadget a minute to load. It's trying to load a large file, and it needs a little bit of time to think.
For those of you who wish to view any of the files used to make this page, there is a tar file below that contains all of the files used in the making, and a ReadMe file with all applicable information on how to run the program.
This map is only available with the Google Sky Gadget due to the limits of the GGeoKML function normally used.
GGeoKML has the following limits:
Raw file size: 3MB
File size when uncompressed: 10MB
Maximum number of network links: 10
Maximum number of features: 1,000
The HabCat KML file was 840k when compressed (which was under the limit), but became 16MB when uncompressed which was problematic due to the 10MB limit. However, the biggest problem was the 17,000 placemarks, which each count as a feature. In order to present the HabCat with the GGeoKML function, the file would have had to be split into at least 18 smaller files, and the viewer could not look at more than one at a time. As this was unpractical, we at SETI opted to use the Google Sky Gadget instead.
The GGeoKML function limits can be found here: http://code.google.com/apis/kml/documentation/mapsSupport.html
For those using a Linux-only machine, there is a KMZ file inside the file attached at the bottom of the page can be opened in the Google Earth application. Google Earth is available for download at http://earth.google.com/download-earth.html.
*Based on reasonable criteria derived from the best available scientific information about necessary conditions for life.