Phi Geminorum

φ Geminorum
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Gemini
Right ascension 07h 53m 29.81390s[1]
Declination +26° 45′ 56.8252″[1]
Apparent magnitude (V) 4.95[2]
Characteristics
Spectral type A3 V[3]
U−B color index +0.08[2]
B−V color index +0.10[2]
Astrometry
Radial velocity (Rv)+8.0[4] km/s
Proper motion (μ) RA: −34.69[1] mas/yr
Dec.: -30.10[1] mas/yr
Parallax (π)14.66 ± 0.73 mas[1]
Distance220 ± 10 ly
(68 ± 3 pc)
Absolute magnitude (MV)+0.81[5]
Orbit
Period (P)581.751 d[6]
Eccentricity (e)0.0[6]
Details
Mass1.9[7] M☉
Luminosity36.5[8] L☉
Surface gravity (log g)4.0[7] cgs
Temperature8,551±291[7] K
Rotational velocity (v sin i)165[9] km/s
Age637[7] Myr
Other designations
φ Gem, 83 Geminorum, BD+27° 1499, FK5 1207, HD 64145, HIP 38538, HR 3067, SAO 79774.[10]
Database references
SIMBADdata

Phi Geminorum, Latinized from φ Geminorum, is a binary star[6] in the constellation Gemini, to the southeast of Pollux. It is visible to the naked eye with an apparent visual magnitude of 4.95.[2] Based upon an annual parallax shift of 14.66 mas,[1] this system is located around 220 light years from the Sun.

The two components of this system have a circular orbit with a period of 582 days.[6] The primary component is an A-type main sequence star with a stellar classification of A3 V.[3] It is around 600 million years old and spinning relatively rapidly with a projected rotational velocity of 165[9] km/s. This rate of spin is giving the star an oblate shape with an equatorial bulge that is 6% larger than the polar radius.[3] The star has nearly double the mass of the Sun and radiates 36.5[8] times the solar luminosity from its outer atmosphere at an effective temperature of 8,551[7] K.

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference vanBelle2012 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference gcrv1953 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference Abt2005 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference David2015 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Royer2007 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).