Gamma Phoenicis

γ Phoenicis
Location of γ Phoenicis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Phoenix
Right ascension 01h 28m 21.92727s[1]
Declination −43° 19′ 05.6502″[1]
Apparent magnitude (V) 3.41[2]
Characteristics
Spectral type M0III[3]
U−B color index +1.85[4]
B−V color index +1.57[4]
Variable type Lb?[5] + β Lyr[6][7]
Astrometry
Radial velocity (Rv)+25.80[8] km/s
Proper motion (μ) RA: −18.06[1] mas/yr
Dec.: −208.63[1] mas/yr
Parallax (π)13.96 ± 0.34 mas[1]
Distance234 ± 6 ly
(72 ± 2 pc)
Absolute magnitude (MV)−0.86[2]
Orbit[9]
Period (P)193.9 d
Semi-major axis (a)0.057[10][note 1]"
(0.30 au)
Eccentricity (e)0.0301
Inclination (i)46.3°
Longitude of the node (Ω)340.2[10]°
Periastron epoch (T)2453670.987
Argument of periastron (ω)
(secondary)		136.8°
Semi-amplitude (K1)
(primary)		−15.845 km/s
Details[6]
Primary
Mass1.3 M☉
Radius50 – 55 R☉
Luminosity562 L☉
Temperature3,802 K
secondary
Mass0.6 M☉
Other designations
CPD−43° 449, FK5 49, GC 1787, HIP 6867, HR 429, HD 9053, SAO 215516
Database references
SIMBADdata

Gamma Phoenicis is a star system in the constellation Phoenix, located around 71.63 parsecs (233.6 ly) distant.[1]

A light curve for Gamma Phoenicis, adapted from Otero (2007)[11]

γ Phoenicis is a spectroscopic binary and a small amplitude variable star. The star system shows regular variations in brightness that were reported as a 97.5 day period in the Hipparcos catalogue,[1] but have since been ascribed to a 194.1-day orbital period with primary and secondary minima.[11] Although the light curve appears to show eclipses, the high orbital inclination suggests the variations are due to ellipsoidal stars as they rotate in their orbit.[6] γ Phoenicis is listed in the General Catalogue of Variable Stars as a possible slow irregular variable with a range from 3.39 to 3.49, the same as reported for the eclipses or ellipsoidal variations.[5]

Only the primary star in the γ Phoenicis system is visible. The second is inferred solely from variations in the radial velocity of the primary star. The primary is a red giant of spectral type M0III, a star that has used up its core hydrogen, then expanded and cooled as it burns a shell of hydrogen around an inert helium core. The two stars are estimated to have masses of 1.3 M☉ and 0.6 M☉ respectively. The primary is over five hundred times more luminous than the sun. The system shows signs of hot coronal activity, although the primary star is too cool for this. It may originate on the secondary, possibly as material is accreted from the cool giant primary.[6]

  1. ^ a b c d e f g Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference XHIP was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Perkins1989 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference MermiliodUBV was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference jorissen was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference magnitud was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Evans1967 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference orbit was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Jancart was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Otero was invoked but never defined (see the help page).


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