28 Monocerotis

28 Monocerotis

A visual band light curve for V645 Monocerotis, adapted from Stift (1979)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Monoceros
Right ascension 08h 01m 13.33574s[2]
Declination −01° 23′ 33.3935″[2]
Apparent magnitude (V) 4.69[3]
Characteristics
Spectral type K4III[4]
U−B color index +1.76[5]
B−V color index +1.49[5]
Astrometry
Radial velocity (Rv)+26.70[6] km/s
Proper motion (μ) RA: +67.60[2] mas/yr
Dec.: −76.26[2] mas/yr
Parallax (π)7.25 ± 0.30 mas[2]
Distance450 ± 20 ly
(138 ± 6 pc)
Absolute magnitude (MV)−1.00[3]
Details
Mass2.193±0.110[7] M☉
Radius47.69+0.46
−2.21[8] R☉
Luminosity524±42[8] L☉
Surface gravity (log g)1.68[9] cgs
Temperature3,999+96
−19[8] K
Metallicity [Fe/H]−0.26[3] dex
Rotational velocity (v sin i)2.2[10] km/s
Other designations
V645 Mon, BD−00 1882, FK5 2620, GC 10870, HD 65953, HIP 39211, HR 3141, SAO 135380[11]
Database references
SIMBADdata

28 Monocerotis is a single[12] star in the equatorial constellation of Monoceros. It has an orange-hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.69.[3] The distance to this star is approximately 450 light years based on parallax,[2] and it has an absolute magnitude of −1.00.[3] The star is drifting further away from the Sun with a radial velocity of +26.7 km/s.[6]

This is an aging giant star with a stellar classification of K4III,[4] having exhausted the supply of hydrogen at its core then cooled and expanded off the main sequence. The spectrum of the star shows abnormally strong lines of CN.[13] It is classified as an FK Comae Berenices variable, varying by 0.02 magnitude over a period of 0.21 days.[14][1] FK Comae Berenices variables are typically rapidly-rotating stars, but the measured projected rotational velocity of 28 Monocerotis is low.[10] The star has expanded to 48 times the radius of the Sun. It is radiating 524 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,999 K.[8]

Measurement of the star's proper motion anomaly by the Gaia spacecraft suggests a companion may be orbiting the star at a distance of 1.9 AU.[7]

  1. ^ a b Cite error: The named reference Stift1979 was invoked but never defined (see the help page).
  2. ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
  3. ^ a b c d e 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. S2CID 119257644. Vizier catalog entry
  4. ^ a b Cite error: The named reference Houk1999 was invoked but never defined (see the help page).
  5. ^ a b Mermilliod, J. C. (2006). "VizieR Online Data Catalog: Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie. 2168. Bibcode:2006yCat.2168....0M.Vizier catalog entry
  6. ^ a b Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  7. ^ a b Cite error: The named reference Kervella2019 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  9. ^ Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497. S2CID 119258214.
  10. ^ a b De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. S2CID 54046583. Vizier catalog entry
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Eggen1996 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).