Astronomy:Delta Monocerotis

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Short description: Star in the constellation Monoceros
Delta Monocerotis
Monoceros constellation map.svg
Red circle.svg
Location of δ Monocerotis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Monoceros
Right ascension  07h 11m 51.860s[1]
Declination −00° 29′ 33.96″[1]
Apparent magnitude (V) 4.15[2]
Characteristics
Spectral type A2V[3] or A0IV[4]
U−B color index +0.04[5]
B−V color index +0.00[5]
Astrometry
Radial velocity (Rv)+15.0±4.1[6] km/s
Proper motion (μ) RA: +0.79[7] mas/yr
Dec.: +4.52[7] mas/yr
Parallax (π)8.49 ± 0.17[7] mas
Distance384 ± 8 ly
(118 ± 2 pc)
Absolute magnitude (MV)−1.20[2]
Details
Mass2.4+0.43
−0.38
[3] M
Luminosity350[8] L
Surface gravity (log g)3.5±0.25[3] cgs
Temperature9,462[8] K
Metallicity [Fe/H]0.00[9] dex
Rotational velocity (v sin i)175.5±1.3[10] km/s
Age405+135
−207
[3] Myr
Other designations
δ Mon, 22 Monocerotis, BD−00°1636, FK5 1187, GC 9518, HD 55185, HIP 34769, HR 2714, SAO 134330, CCDM J07119-0030A, WDS J07119-0030A[11]
Database references
SIMBADdata

Delta Monocerotis, which is Latinized from δ Monocerotis, is a single star[12] in the constellation of Monoceros, positioned about a half degree south of the celestial equator. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.15.[2] The distance to this star is approximately 384 light years based on parallax.[7] It is drifting further away from the Sun with a radial velocity of about +15 km/s,[6] having come to within 88 light-years some 7.3 million years ago.[2] The star has an absolute magnitude of −1.20.[2]

The Bright Star Catalogue assigns this star a stellar classification of A2V, suggesting this is an A-type main-sequence star.[3][13] However, Houk and Swift (1999) found a more evolved subgiant class of A0IV.[4] It has around 2.4 times the mass of the Sun and is an estimated 405 million years old.[3] The star has a high rate of spin with a projected rotational velocity of 175.5 km/s,[10] giving it an equatorial bulge that is 5% larger than the polar radius.[14] It is radiating 350 times the luminosity of the Sun from its photosphere at an effective temperature of 9,462 K.[8]

It has one reported visual companion, designated component B, at an angular separation of 32.0 and visual magnitude 13.0.[15]

References

  1. 1.0 1.1 Høg, E. et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27. Bibcode2000A&A...355L..27H. 
  2. 2.0 2.1 2.2 2.3 2.4 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A.  Vizier catalog entry
  3. 3.0 3.1 3.2 3.3 3.4 3.5 Gullikson, Kevin et al. (August 2016). "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars". The Astronomical Journal 152 (2): 13. doi:10.3847/0004-6256/152/2/40. 40. Bibcode2016AJ....152...40G. 
  4. 4.0 4.1 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey 5. Bibcode1999MSS...C05....0H. 
  5. 5.0 5.1 Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers 42 (2): 443. Bibcode2014JAVSO..42..443M. Vizier catalog entry
  6. 6.0 6.1 Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode2006AstL...32..759G. 
  7. 7.0 7.1 7.2 7.3 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode2007A&A...474..653V.  Vizier catalog entry
  8. 8.0 8.1 8.2 Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars". Astronomy & Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. Bibcode2012A&A...537A.120Z.  Vizier catalog entry
  9. Gontcharov, G. A. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters 38 (12): 771–782. doi:10.1134/S1063773712120031. Bibcode2012AstL...38..771G.  Vizier catalog entry
  10. 10.0 10.1 Díaz, C. G. et al. (July 2011). "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum". Astronomy & Astrophysics 531: A143. doi:10.1051/0004-6361/201016386. Bibcode2011A&A...531A.143D. 
  11. "del Mon". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del+Mon. 
  12. Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode2008MNRAS.389..869E. 
  13. Hoffleit, D.; Warren, W. H. (1995). "Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H 5050. Bibcode1995yCat.5050....0H. 
  14. van Belle, Gerard T. (March 2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review 20 (1): 51. doi:10.1007/s00159-012-0051-2. Bibcode2012A&ARv..20...51V. 
  15. Dommanget, J.; Nys, O. (2002). "VizieR Online Data Catalog: CCDM (Catalog of Components of Double & Multiple stars) (Dommanget+ 2002)". VizieR On-line Data Catalog: I/274. Originally Published in: Observations et Travaux 54 1274. Bibcode2002yCat.1274....0D.  Vizier catalog entry