Teegarden's star

Teegarden's Star (SO J025300.5+165258, 2MASS J02530084+1652532, LSPM J0253+1652) is an M-type red dwarf in the constellation Aries, located about 12 light years from the Solar System. Despite its proximity to Earth it is a dim magnitude 15 and can only be seen through large telescopes. This star was found to have a very large proper motion of about 5 arcseconds per year. Only seven stars with such large proper motions are currently known.

Teegarden's Star was discovered in 2003 using asteroid tracking data that had been collected years earlier. This data set is a digital archive created from optical images taken over a 5-year period by the Near Earth Asteroid Tracking (NEAT) program using two 1-m telescopes located on Maui. The star is named after the discovery team leader, Bonnard J. Teegarden, an astrophysicist at NASA's Goddard Space Flight Center.

Astronomers have long thought it was quite likely that many undiscovered dwarf stars exist within 20 light years of Earth, because stellar-population surveys show the count of known nearby dwarf stars to be lower than otherwise expected and these stars are dim and easily overlooked. Teegarden's team thought that these dim stars might be found by data mining some of the huge optical sky survey data sets taken by various programs for other purposes in previous years. So they reexamined the NEAT asteroid tracking data set and found this star. The star was then located on photographic plates from the Palomar Sky Survey taken in 1951. This discovery is significant as the team did not have direct access to any telescopes and did not include professional astronomers at the time of the discovery.