HD 50281

HD 50281 is a star in the equatorial constellation of Monoceros. It is orange in hue with an apparent visual magnitude of 6.58,[2] which lies at or below the typical limit of visibility to the naked eye. The star is located at a distance of 28.5 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −7.2 km/s.[4]

HD 50281
Observation data
Epoch J2000      Equinox J2000
Constellation Monoceros
Right ascension  06h 52m 18.05045s[1]
Declination −05° 10′ 25.36617″[1]
Apparent magnitude (V) 6.58[2]
Characteristics
Evolutionary stage main sequence
Spectral type K3.5 V[3]
B−V color index 1.071±0.008[2]
Astrometry
Radial velocity (Rv)−7.20±0.15[4] km/s
Proper motion (μ) RA: −543.616[1] mas/yr
Dec.: −3.491[1] mas/yr
Parallax (π)114.2968 ± 0.0465[1] mas
Distance28.54 ± 0.01 ly
(8.749 ± 0.004 pc)
Absolute magnitude (MV)6.87[5]
Details
Mass0.79[6] M☉
Radius0.73+0.01
−0.02[1] R☉
Luminosity0.225[1] L☉
Surface gravity (log g)4.64[6] cgs
Temperature4,712±8.5[7] K
Metallicity [Fe/H]+0.01[8] dex
Rotational velocity (v sin i)5.5[6] km/s
Age1.88[6] Gyr
Other designations
88 G. Monocerotis, BD−05°1844, GJ 250, HD 50281, HIP 32984, HR 2534, SAO 133805, WDS J06523−0510, LFT 494, LHS 1875, LTT 2662[9]
Database references
SIMBADA
B

This object is an ordinary K-type main-sequence star with a stellar classification of K3.5 V.[3] It is nearly two billion years old and is spinning with a projected rotational velocity of 5.5 km/s.[6] The metallicity of this star – what astronomers term the abundance of elements with atomic numbers greater than helium – is near solar. The star has 79%[6] of the mass of the Sun and 73%[1] of the Sun's radius. It is radiating 22.5%[1] of the luminosity of the Sun from its photosphere at an effective temperature of 4,712 K.[7]

A magnitude 10.16 common proper motion companion,[10] designated component B, is located at an angular separation of 58.8″ along a position angle of 181° from the primary, as of 2015.[10] This is a suspected binary star system[11] with components of individual visual magnitude 10.6 and 11.1,[10] and a class of M2.5 V.[12] The coordinates of this companion are a source of X-ray emission.[13] A third companion, magnitude 14.04 component C, lies at a separation of 9.6″ from component B.[10]

References
  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. Gaia DR2 record for this source at VizieR.
  2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
  3. Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
  4. Bailer-Jones, C.A.L.; et al. (2018). "New stellar encounters discovered in the second Gaia data release". Astronomy & Astrophysics. 616: A37. arXiv:1805.07581. Bibcode:2018A&A...616A..37B. doi:10.1051/0004-6361/201833456.
  5. Holmberg, J.; et al. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941–947. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191.
  6. Luck, R. Earle (January 2017). "Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants". The Astronomical Journal. 153 (1): 19. arXiv:1611.02897. Bibcode:2017AJ....153...21L. doi:10.3847/1538-3881/153/1/21. 21.
  7. Kovtyukh, V. V.; et al. (2003). "High precision effective temperatures for 181 F-K dwarfs from line-depth ratios". Astronomy and Astrophysics. 411 (3): 559–564. arXiv:astro-ph/0308429. Bibcode:2003A&A...411..559K. doi:10.1051/0004-6361:20031378.
  8. Rojas-Ayala, Bárbara; et al. (April 2012). "Metallicity and Temperature Indicators in M Dwarf K-band Spectra: Testing New and Updated Calibrations with Observations of 133 Solar Neighborhood M Dwarfs" (PDF). The Astrophysical Journal. 748 (2): 93. arXiv:1112.4567. Bibcode:2012ApJ...748...93R. doi:10.1088/0004-637X/748/2/93.
  9. "HD 50281". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-06-06.
  10. Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122: 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  11. Mason, Brian D.; et al. (May 2018). "Speckle Interferometry of Red Dwarf Stars". The Astronomical Journal. 155 (5): 14. arXiv:1804.07845. Bibcode:2018AJ....155..215M. doi:10.3847/1538-3881/aab9b8. 215.
  12. Kirkpatrick, J. D.; et al. (1991). "A standard stellar spectral sequence in the red/near-infrared - Classes K5 to M9". Astrophysical Journal Supplement Series. 77: 417. Bibcode:1991ApJS...77..417K. doi:10.1086/191611.
  13. Johnson, H. M. (April 1986). "An Unbiased X-Ray Sampling of Stars within 25 Parsecs of the Sun". Astrophysical Journal. 303: 470. Bibcode:1986ApJ...303..470J. doi:10.1086/164092. hdl:2060/19860004737.
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