Phi Phoenicis

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Phi Phoenicis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Phoenix
Right ascension 01h 54m 22.03347s[1]
Declination −42° 29′ 49.0183″[1]
Apparent magnitude (V) 5.115[2]
Characteristics
Spectral type B9 V[3] + ?
U−B color index −0.125[2]
B−V color index −0.06[2]
Astrometry
Radial velocity (Rv)5.5±0.5[4] km/s
Proper motion (μ) RA: −33.91[1] mas/yr
Dec.: −28.17[1] mas/yr
Parallax (π)10.63 ± 0.37[1] mas
Distance310 ± 10 ly
(94 ± 3 pc)
Absolute magnitude (MV)0.26±0.13[5]
Orbit[6]
Period (P)1,126.11±0.16 d
Semi-major axis (a)36.3 mas[5]
Eccentricity (e)0.589±0.004
Inclination (i)93±4.7[5]°
Periastron epoch (T)2453766.2 ± 2.2
Argument of periastron (ω)
(secondary)
3.52±0.01 [rad]°
Semi-amplitude (K1)
(primary)
9.21±0.09 km/s
Details
φ Phe A
Mass2.85±0.04[7] M
Radius9.5[8] R
Luminosity95[7] L
Surface gravity (log g)3.79±0.10[5] cgs
Temperature10,612±200[5] K
Metallicity [Fe/H]0.15[5] dex
Rotation9.53077±0.00011 d[6]
Rotational velocity (v sin i)13.5[9] km/s
φ Phe B
Mass0.9[5] M
Other designations
φ Phe, CPD−43° 583, FK5 1053, GC 2315, HD 11753, HIP 8882, HR 558, SAO 215697[10]
Database references
SIMBADdata

Phi Phoenicis, Latinized from φ Phoenicis, is a binary star[5] system in the southern constellation of Phoenix. It is faintly visible to the naked eye with an apparent visual magnitude of 5.1.[2] Based upon an annual parallax shift of 10.63 mas as seen from Earth,[1] it is located around 310 light years from the Sun. It is moving away from the Sun with a radial velocity of 5.5 km/s.[4]

This is a single-lined spectroscopic binary star system with an orbital period of three years and a large eccentricity of 0.6.[6][5] The radial velocity variation of the system was announced by Campbell & Moore (1928), although orbital elements were not determined until Leone & Catanzard (1999). Data from the Hipparcos satellite appeared to show it was a triple star system. However, subsequent observations did not bear this out. This binary system is inclined by 93° to the line of sight, which may mean it is an eclipsing binary. The visual magnitude difference between the components is 5.7.[5]

The primary component is a B-type main-sequence star with a stellar classification of B9 V.[3] It is a type of chemically peculiar star known as an HgMn star, which means it shows surface overabundancies of certain elements including mercury and manganese, and deficiencies in others including helium, cobalt, and so forth.[9] The star has about three[7] times the mass of the Sun and is radiating 95[7] times the Sun's luminosity from its photosphere at an effective temperature of about 10,612 K.[5]

The elemental abundances are distributed inhomogeneously across the surface of the primary. In particular, the star forms spots with high or low abundances of yttrium, strontium, titanium, and chromium.[6] The star may show magnetic field variations that are correlated with these elemental spots,[6][3] although this is disputed.[11] The spot configurations vary on monthly or yearly time scales. By tracking the spots, an estimated rotation period of 9.5 days is determined, along with evidence for "very weak" differential rotation. The pole of rotation is inclined to the line of sight by an angle of about 53°.[6]

References[edit]

  1. ^ 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.
  2. ^ a b c d Cousins, A. W. J. (1972), "UBV Photometry of Some Very Bright Stars", Monthly Notes of the Astronomical Society of Southern Africa, 31: 69, Bibcode:1972MNSSA..31...69C.
  3. ^ a b c Hubrig, S.; et al. (November 2012), "Magnetic fields of HgMn stars", Astronomy & Astrophysics, 547: 24, arXiv:1208.2910, Bibcode:2012A&A...547A..90H, doi:10.1051/0004-6361/201219778, A90.
  4. ^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. ^ a b c d e f g h i j k Pourbaix, D.; et al. (August 2013), "The multiplicity of φ Phe revisited", Astronomy & Astrophysics, 556: 4, arXiv:1304.7756, Bibcode:2013A&A...556A..45P, doi:10.1051/0004-6361/201321699, A45
  6. ^ a b c d e f Korhonen, H.; et al. (May 2013), "Chemical surface inhomogeneities in late B-type stars with Hg and Mn peculiarity. I. Spot evolution in HD 11753 on short and long time scales", Astronomy & Astrophysics, 553: 16, arXiv:1302.5119, Bibcode:2013A&A...553A..27K, doi:10.1051/0004-6361/201220951, A27.
  7. ^ a b c d Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
  8. ^ Shulyak, D.; et al. (2014), "Interferometry of chemically peculiar stars: Theoretical predictions versus modern observing facilities", Monthly Notices of the Royal Astronomical Society, 443 (2): 1629, arXiv:1406.6093, Bibcode:2014MNRAS.443.1629S, doi:10.1093/mnras/stu1259.
  9. ^ a b Briquet, M.; et al. (February 2010), "Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753", Astronomy and Astrophysics, 511: 6, arXiv:1003.1902, Bibcode:2010A&A...511A..71B, doi:10.1051/0004-6361/200913775, A71.
  10. ^ "phi Phe". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-21.
  11. ^ Kochukhov, O.; et al. (June 2013), "Are there tangled magnetic fields on HgMn stars?", Astronomy & Astrophysics, 554: 12, arXiv:1304.6717, Bibcode:2013A&A...554A..61K, doi:10.1051/0004-6361/201321467, A61.