Hipparcos Astronomy Explorer

Explores positions, velocities, magnitudes, and colors of 118k nearby Hipparcos single stars and clusters.

This Live Script explores the Hipparcos all-sky survey (1989-93) catalog of 118,218 stars in the neighborhood of Sun. The catalog includes celestial angular coordinates, distance in the form of parallax angle, proper motion components, apparent visual magnitude, and color index values in Johnson UVB photometric system and Cousins UVBRI system which are sensitive to surface temperature.

From the apparent magnitudes and distances, the absolute magnitudes (a measure of intrinsic luminosity) are derived. The absolute magnitude is correlated with the temperature information in a Hertzsprung–Russell diagram that separates stars in different life stages. A clustering algorithm operating on the 4d space of proper motion and angular position is used to identify a co-moving stellar cluster.

This script may be applied to the more extensive Tycho2 Catalogue derived from the Hipparcos alignment system with astrometric information for 2.5 million stars in the solar neighborhood, essentially all stars down to magnitude 11, and to the Gaia data release 3 (2020) with astrometric information for 1.46 billion stars with a magnitude limit of about 21. The script illustrates import of a catalog obtained with the freely available TOPCAT application and also a more direct import of a more extensive version of the original Hipparcos catalog.

The data analysis techniques in the script may interest students and instructors of astronomy and physics. The script includes numerous hyperlinks to MathWorks documentation and literature references. 'Try this' suggestions are included for further exploration. Challenges are provided for the more ambitious. Additional similar educational Live Scripts are available at File Exchange.