2MASS J154043.42−510135.7

2MASS J154043.42−510135.7 (2M1540) is a red dwarf of spectral type M7, located in Norma at approximately 17 light-years from Earth. It was discovered in 2014. It is the nearest known M7 dwarf.[2]

2MASS J154043.42−510135.7
Observation data
Epoch J2000      Equinox J2000
Constellation Norma
Right ascension 15h 40m 43.537s[1]
Declination −51° 01 35.968[1]
Apparent magnitude (V) 15.26[2]
Spectral type M7V[2]
Proper motion (μ) RA: +1.954[2] mas/yr
Dec.: −0.330[2] mas/yr
Parallax (π)188.0498 ± 0.0939[1] mas
Distance17.344 ± 0.009 ly
(5.318 ± 0.003 pc)
Absolute bolometric
Mass0.090±0.010 M
Luminosity0.000603 L
Temperature2621±100 K
Database references


Its discovery was announced in 2014 by Kirkpatrick et al.[3] and independently by Pérez Garrido et al.[2]

Kirkpatrick and colleagues found a few thousand new high proper motion objects under the AllWISE program of study of images, taken by Wide-field Infrared Survey Explorer (WISE). 2M1540 was one of these high proper motion objects. They named it WISEA J154045.67-510139.3 and assigned it spectral type M6.[3]

Pérez Garrido and colleagues were looking for high proper motion sources in the 2MASSWISE cross-match. They named it 2MASS J154043.42−510135.7 (2M1540 for short) and classified it as an M7.0±0.5 dwarf.[2]

Since the trigonometric distance of 2M1540 agreed with its spectrophotometric distances, computed for a single object, it was concluded that it is not an equal-mass binary.[2]


  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  2. Pérez Garrido, A.; Lodieu, N.; Béjar, V. J. S.; Ruiz, M. T.; Gauza, B.; Rebolo, R.; Zapatero Osorio, M. R. (2014). "2MASS J154043.42-510135.7: a new addition to the 5 pc population". Astronomy & Astrophysics. 567: A6. arXiv:1405.5439. Bibcode:2014A&A...567A...6P. doi:10.1051/0004-6361/201423615. S2CID 118704532.
  3. Kirkpatrick, J. Davy; Schneider, Adam; Fajardo-Acosta, Sergio; Gelino, Christopher R.; Mace, Gregory N.; Wright, Edward L.; Logsdon, Sarah E.; McLean, Ian S.; Cushing, Michael C.; Skrutskie, Michael F.; Eisenhardt, Peter R.; Stern, Daniel; Baloković, Mislav; Burgasser, Adam J.; Faherty, Jacqueline K.; Lansbury, George B.; Rich, J. A.; Skrzypek, Nathalie; Fowler, John W.; Cutri, Roc M.; Masci, Frank J.; Conrow, Tim; Grillmair, Carl J.; McCallon, Howard L.; Beichman, Charles A.; Marsh, Kenneth A. (2014). "The AllWISE Motion Survey and the Quest for Cold Subdwarfs". The Astrophysical Journal. 783 (2): 122. arXiv:1402.0661. Bibcode:2014ApJ...783..122K. doi:10.1088/0004-637X/783/2/122. S2CID 30949660.
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