WISE 1541−2250

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Coordinates: Sky map 15h 41m 51.57s, −22° 50′ 25.03″

WISEPA J154151.66−225025.2
Observation data
Epoch MJD 55424.68[1]      Equinox J2000[1]
Constellation Libra
Right ascension 15h 41m 51.57s[1]
Declination −22° 50′ 25.03″[1]
Spectral type Y0.5[2]
Apparent magnitude (J (MKO filter system)) 21.16 ± 0.36[1]
Apparent magnitude (H (MKO filter system)) 20.99 ± 0.52[1]
Proper motion (μ) RA: −895±5[3] mas/yr
Dec.: −88±5[3] mas/yr
Parallax (π)175.1 ± 4.4[3] mas
Distance18.6 ± 0.5 ly
(5.7 ± 0.1 pc)
Mass12 (8–12)[4] MJup
Radius1.01 (1.01–1.07)[4] RJup
Surface gravity (log g)4.50 (4.25–4.5)[4] cgs
Temperature350[4] K
Other designations
WISEPA J154151.66−225025.2[1]
WISEP J1541−2250[4]
WISE J1541−2250[1]
WISE 1541−2250[1]
Database references
Artist's vision of a Y-dwarf

WISE 1541−2250 (full designation WISEPA J154151.66−225025.2) is a sub-brown or brown dwarf of spectral class Y0.5,[2] located in the constellation Libra at approximately 18.6 light-years from Earth.[3] 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.[5] (For really close brown dwarfs see, for example, Luhman 16, WISE 1506+7027, Epsilon Indi Ba, Bb, or UGPS 0722-05). It is not the farthest known Y-type brown dwarf to Earth.

History of observations[edit]


WISE 1541−2250 was discovered in 2011 from data collected by the Wide-field Infrared Survey Explorer (WISE) in the infrared at a wavelength of 40 cm (16 in), whose mission lasted from December 2009 to February 2011. WISE 1541−2250 has two discovery papers: Kirkpatrick et al. (2011) and Cushing et al. (2011) with mostly the same authors and published nearly simultaneously.[1][4]

  • Kirkpatrick et al. presented the discovery of 98 brown dwarf systems with components of spectral types M, L, T and Y, among which was WISE 1541−2250.[1][~ 1]
  • Cushing et al. presented the discovery of seven brown dwarfs, one of the T9.5 type and six of the Y-type, the first members of the Y spectral class discovered and spectroscopically confirmed, including an "archetypal member" of the Y spectral class, WISE 1828+2650, and WISE 1541−2250.[4] These seven objects are also the faintest seven of 98 brown dwarfs presented in Kirkpatrick et al. (2011).[1]


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+0.15
pc, or 18.6 ± 0.5 ly.[3]

For several months after its discovery, before the publication of its parallax by Kirkpatrick et al. in 2012,[2] 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+1.3
pc, or 9.3+4.1
ly.[1] Also, there were other estimates: spectrophotometric distance estimate 8.2 pc (26.7 ly),[1] and photometric distance estimate 1.8+0.2
pc (5.9+0.6

Space motion[edit]

WISE 1541−2250 has proper motion of about 899 milliarcseconds per year.[3]

Spectral class and temperature[edit]

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[4] (about 77 °C / 170 °F). Its spectral class is Y0.5[2] (initially was estimated as Y0).[1][4]

See also[edit]

The other six discoveries of brown dwarfs, published in Cushing et al. (2011):[4]



  1. ^ These 98 brown-dwarf systems are among the first brown-dwarf systems discovered in data collected by WISE and six discoveries were published earlier (however, also listed in Kirkpatrick et al. (2011)) in Mainzer et al. (2011) and Burgasser et al. (2011), and the other discoveries were published later.


  1. ^ a b c d e f g h i j k l m n o Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Marsh, Kenneth A.; Wright, Edward L.; Mainzer, A.; Eisenhardt, Peter R.; McLean, Ian S.; Thompson, Maggie A.; Bauer, James M.; Benford, Dominic J.; Bridge, Carrie R.; Lake, Sean E.; Petty, Sara M.; Stanford, S. A.; Tsai, Chao-Wei; Bailey, Vanessa; Beichman, Charles A.; Bloom, Joshua S.; Bochanski, John J.; Burgasser, Adam J.; Capak, Peter L.; Cruz, Kelle L.; Hinz, Philip M.; Kartaltepe, Jeyhan S.; Knox, Russell P.; Manohar, Swarnima; Masters, Daniel; Morales-Calderon, Maria; Prato, Lisa A.; Rodigas, Timothy J.; Salvato, Mara; Schurr, Steven D.; Scoville, Nicholas Z.; Simcoe, Robert A.; Stapelfeldt, Karl R.; Stern, Daniel; Stock, Nathan D.; Vacca, William D. (2011). "The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal Supplement. 197 (2): 19. arXiv:1108.4677v1Freely accessible. Bibcode:2011ApJS..197...19K. doi:10.1088/0067-0049/197/2/19. 
  2. ^ a b c d Kirkpatrick, J. D.; Gelino, C. R.; Cushing, M. C.; Mace, G. N.; Griffith, R. L.; Skrutskie, M. F.; Marsh, K. A.; Wright, E. L.; Eisenhardt, P. R.; McLean, I. S.; Mainzer, A. K.; Burgasser, A. J.; Tinney, C. G.; Parker, S.; Salter, G. (2012). "Further Defining Spectral Type "Y" and Exploring the Low-mass End of the Field Brown Dwarf Mass Function". The Astrophysical Journal. 753 (2): 156. arXiv:1205.2122Freely accessible. Bibcode:2012ApJ...753..156K. doi:10.1088/0004-637X/753/2/156. 
  3. ^ a b c d e Tinney, C. G.; Faherty, Jacqueline K.; Kirkpatrick, J. Davy; Cushing, Mike; Morley, Caroline V.; Wright, Edward L. (2014). "The Luminosities of the Coldest Brown Dwarfs". The Astrophysical Journal. 796 (1): 39. arXiv:1410.0746Freely accessible. Bibcode:2014ApJ...796...39T. doi:10.1088/0004-637X/796/1/39. 
  4. ^ a b c d e f g h i j k Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Mainzer, A.; Marsh, Kenneth A.; Beichman, Charles A.; Burgasser, Adam J.; Prato, Lisa A.; Simcoe, Robert A.; Marley, Mark S.; Saumon, D.; Freedman, Richard S.; Eisenhardt, Peter R.; Wright, Edward L. (2011). "The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal. 743 (1): 50. arXiv:1108.4678Freely accessible. Bibcode:2011ApJ...743...50C. doi:10.1088/0004-637X/743/1/50. 
  5. ^ "NASA'S Wise Mission Discovers Coolest Class of Stars". WISE Mission News (2011-263). 2011-08-23. 

External links[edit]