Observation data Epoch J2000 Equinox J2000 |
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Constellation | Norma |
Right ascension | 15h 40m 43.42s |
Declination | –51° 01′ 35.7″ |
Database references | |
SIMBAD | data |
2MASS J154043.42−510135.7 (2M1540) is a red dwarf of spectral type M7, located in constellation Norma at approximately 15 light-years from Earth. It was discovered in 2014. It is the nearest known M7 dwarf.[1]
Discovery
Discovery of 2M1540 was announced in 2014 by Kirkpatrick et al.[2] and independently by Pérez Garrido et al.[1]
Kirkpatrick and colleagues found few thousands of 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.[2]
Pérez Garrido and colleagues found this M-type dwarf, looking for high proper motion sources in the 2MASS–WISE cross-match. They named it 2MASS J154043.42−510135.7 (2M1540) and classified it as an M7.0±0.5 dwarf.[1]
Distance
Source | Parallax, mas | Distance, pc | Distance, ly | Distance, Pm | Ref. |
---|---|---|---|---|---|
Kirkpatrick et al. (2014) (spectrophotometric, single) |
~5.9 | ~19.2 | [2] | ||
Kirkpatrick et al. (2014) (spectrophotometric, equal-magnitude double) |
~8.3 | ~27.1 | [2] | ||
Kirkpatrick et al. (2014) | 165±41 | 6.1+2.0 −1.2 |
19.8+6.5 −3.9 |
187.0+61.8 −37.2 |
[2] |
Pérez Garrido et al. (2014) | 228±24 | 4.4+0.5 −0.4 |
14.3+1.7 −1.4 |
135.3+15.9 −12.9 |
[1] |
Pérez Garrido et al. (2014) (recomputed Kirkpatrick et al. (2014) data) |
186±24 | 5.4+0.8 −0.6 |
17.5+2.6 −2.0 |
165.9+24.6 −19.0 |
[1][2] |
Pérez Garrido et al. (2014) (Kirkpatrick et al. (2014) and their points) |
208±20 | 4.8+0.5 −0.4 |
15.7+1.7 −1.4 |
148.3+15.8 −13.0 |
[1][2] |
Pérez Garrido et al. (2014) (spectrophotometric, M7 templates) |
4.38+0.46 −0.58 |
14.3+1.5 −1.9 |
[1] | ||
Pérez Garrido et al. (2014) (spectrophotometric, M6.5 templates) |
5.02±0.59 | 16.4±1.9 | [1] | ||
Pérez Garrido et al. (2014) (spectrophotometric, K-band) |
4.3+0.4 −0.2 |
14.0+1.3 −0.7 |
[1] |
Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.
While each of the distance estimates have fairly large errors in them, the estimated average of the distances is about 15.3 light years, which agrees well with the error bars on each measurement.
Since trigonometric distance of 2M1540 agree with its spectrophotometric distances, computed for single object, it was concluded that it is not an equal-mass binary.[1]
References
- ^ a b c d e f g h i j 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.
- ^ a b c d e f g 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.
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