WISE 1541−2250


WISE 1541−2250 is a sub-brown or brown dwarf of spectral class Y0.5, located in the constellation Libra at approximately 18.6 light-years from Earth. This object received popular attention when its discovery was announced in 2011 at a distance estimated to be only about 9 light-years, which would have made it the closest brown dwarf known.. It is not the farthest known Y-type brown dwarf to Earth.

History of observations

Discovery

WISE 1541−2250 was discovered in 2011 from data collected by the Wide-field Infrared Survey Explorer in the infrared at a wavelength of 40 cm, whose mission lasted from December 2009 to February 2011. WISE 1541−2250 has two discovery papers: Kirkpatrick et al. and Cushing et al. with mostly the same authors and published nearly simultaneously.
Currently the most accurate distance estimate of WISE 1541−2250 is a trigonometric parallax, published in 2014 by Tinney et al.: 0.1751 ± 0.0044 arcsec, corresponding to a distance 5.71 pc, or 18.6 ± 0.5 ly.
For several months after its discovery, before the publication of its parallax by Kirkpatrick et al. in 2012, WISE 1541−2250 was considered to be the nearest known brown dwarf at approximately 9 light-years from the Sun, and the seventh-nearest of all star systems, at slightly more than twice the distance of the nearest known star system Alpha Centauri. This view existed because of a very rough preliminary parallax with a baseline of 1.2 years, published in the discovery paper: 0.351 ± 0.108 arcsec, corresponding to a distance 2.8 pc, or 9.3 ly. Also, there were other estimates: spectrophotometric distance estimate 8.2 pc, and photometric distance estimate 1.8 pc.

Space motion

WISE 1541−2250 has proper motion of about 899 milliarcseconds per year.

Spectral class and temperature

WISE 1541−2250 is among the first known examples of a Y-class brown dwarf, the coldest spectral class of stars, and has temperature about 350 K. Its spectral class is Y0.5.