Rho Phoenicis

Rho Phoenicis (ρ Phoenicis) is a variable star in the constellation of Phoenix. From parallax measurements by the Gaia spacecraft, it is located at a distance of 240 light-years (74 parsecs) from Earth.[1]

Rho Phoenicis
Observation data
Epoch J2000      Equinox J2000
Constellation Phoenix
Right ascension 00h 50m 41.19s[1]
Declination −50° 59′ 12.55″[1]
Apparent magnitude (V) 5.17 – 5.27[2]
Characteristics
Spectral type F3III[3]
U−B color index 0.13[4]
B−V color index 0.36[4]
Variable type δ Scuti[2][4]
Astrometry
Radial velocity (Rv)22.0[5] km/s
Proper motion (μ) RA: 62.54[1] mas/yr
Dec.: 44.42[1] mas/yr
Parallax (π)13.6164 ± 0.1220[1] mas
Distance240 ± 2 ly
(73.4 ± 0.7 pc)
Absolute magnitude (MV)+0.87[6]
Details
Mass2.13[7] M☉
Radius4.14[1] R☉
Luminosity35[8] L☉
Surface gravity (log g)3.52[7] cgs
Temperature6,917 ± 124[7] K
Metallicity[M/H] = 0.10[7]
Metallicity [Fe/H]0.02[7] dex
Age1.00[7] Gyr
Other designations
CD−51°209, FK5 2056, HD 4919, HIP 3949, HR 242, SAO 232203[9]
Database references
SIMBADdata

This star is classified as an F-type giant with a spectral type of F3III, and in the HR diagram it occupies in the lower part of the instability strip. Rho Phoenicis is Delta Scuti variable, changing its visual apparent magnitude between 5.17 and 5.27 with a period of around 0.1–0.2 days.[4][2] The pulsation period seems to vary in a timescale of weeks, which indicates the star is not a simple radial pulsator.[10] The analysis of the temperature variations over the pulsation cycles also supports this conclusion.[11] It is not clear if the pulsation period really is variable, or if the light curve is simply the sum of multiple stable pulsation frequencies.[12]

Stellar evolution models indicate that Rho Phoenicis has about 2.1 times the solar mass and an age of around 1 billion years.[7] This star is shining with 35 times the solar luminosity[8] and has an effective temperature of 6,900 K.[7] Its metallicity is high, with an overall metal abundance 25% greater the solar value.[7] Gaia Data Release 2 discovered a star with the same proper motion and parallax as Rho Phoenicis. It has an apparent magnitude of 14.6 (G band) and is at a separation of 7.9 arcseconds.[13]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085.
  3. Houk, N. (1978). "Michigan atalogue of two dimensional spectral types for the HD stars, Vol. 2". Michigan Spectral Survey. 2. Bibcode:1978mcts.book.....H.
  4. Garcia, J. R.; Cebral, J. R.; Scoccimarro, E. R.; Wahnon, P.; Arena, R.; Bazterra, V.; Pellizza, L.; Risi, A.; Rodriguez, M. L.; Zimmermann, M. (1995). "A catalogue of variable stars in the lower instability strip". Astronomy and Astrophysics Supplement Series. 109: 201. Bibcode:1995A&AS..109..201G.
  5. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065.
  6. Holmberg, J.; Nordström, B.; Andersen, J. (2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191.
  7. Casagrande, L.; et al. (June 2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy and Astrophysics, 530: A138, arXiv:1103.4651, Bibcode:2011A&A...530A.138C, doi:10.1051/0004-6361/201016276.
  8. McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x
  9. "Rho Phe". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 February 2019.
  10. Smyth, M. J.; Stobie, R. S.; Shobbrook, R. R. (1975). "Frequency analysis of the three Delta Scuti stars BS 3265, 1653 and 242". Monthly Notices of the Royal Astronomical Society. 171: 143. Bibcode:1975MNRAS.171..143S. doi:10.1093/mnras/171.1.143.
  11. Sullivan, D. J.; Trodahl, H. J. (1978). "Temperature variations in rho Phe". Monthly Notices of the Royal Astronomical Society. 183: 201. Bibcode:1978MNRAS.183..201S. doi:10.1093/mnras/183.2.201.
  12. Kurtz, D. W. (1980). "On the stability of observed frequencies in del SCT stars : A reanalysis of the Tuc". Monthly Notices of the Royal Astronomical Society. 193: 61. Bibcode:1980MNRAS.193...61K. doi:10.1093/mnras/193.1.61.
  13. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
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