Delta Monocerotis

Delta Monocerotis
Location of δ Monocerotis (circled)
Observation data
Epoch J2000      Equinox J2000
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 mas[7]
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]

  1. ^ a b Cite error: The named reference Høg2000 was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference XHIP was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference Gullikson2016 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Houk1999 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Mallama2014 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Díaz2011 was invoked but never defined (see the help page).
  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 Hoffleit1991 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference vanBelle2012 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference CCDM was invoked but never defined (see the help page).