Rho2 Arietis

Rho2 Arietis is an M-type red giant star in the northern constellation of Aries. With an annual parallax shift of 9.28 mas,[1] it is approximately 350 light-years (110 parsecs) distant from the Earth.

For other stars with this Bayer designation, see ρ Arietis.
ρ2 Arietis
Location of ρ2 Arietis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Aries
Right ascension  02h 55m 48.49800s[1]
Declination +18° 19′ 53.9029″[1]
Apparent magnitude (V) 5.93[2] (5.45–6.01)[3]
Characteristics
Spectral type M6 III[4]
U−B color index +1.12[2]
B−V color index +1.51[2]
R−I color index 2.17[5]
Variable type SRb[3]
Astrometry
Radial velocity (Rv)+46.0[6] km/s
Proper motion (μ) RA: −7.78[1] mas/yr
Dec.: −14.98[1] mas/yr
Parallax (π)9.28 ± 0.30[1] mas
Distance350 ± 10 ly
(108 ± 3 pc)
Absolute magnitude (MV)+0.60[7]
Details
Mass1.14±0.2[8] M☉
Luminosity1,995[9] L☉
Surface gravity (log g)0.30[10] cgs
Temperature3,341[8] K
Metallicity [Fe/H]–0.24[10] dex
Other designations
ρ2 Ari, 45 Arietis, RZ Arietis, BD+17 457, HD 18191, HIP 13654, HR 867, SAO 93189.[11]
Database references
SIMBADdata

Rho2 Arietis is classified as a semiregular variable star with periods of 49.9 and 54.8 days.[12] It varies in visual magnitude between 5.45 and 6.01. It has the variable star designation, RZ Arietis.[3] It is generally considered to be an asymptotic giant branch star, having exhausted its core helium.[13] Based on comparison of its current temperature and luminosity with theoretical evolutionary tracks, its initial mass is estimated to have been 1.3 M☉ and its mass now is 1.14 M☉.[8]

References
  1. van Leeuwen, F. (November 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. Lee, T. A. (October 1970), "Photometry of high-luminosity M-type stars", Astrophysical Journal, 162: 217, Bibcode:1970ApJ...162..217L, doi:10.1086/150648.
  3. V* RZ Ari, entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250.
  4. Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333.
  5. HR 867, entry, Bright Star Catalogue, 5th Revised Ed., D. Hoffleit and W. H. Warren, Jr., 1991, CDS ID V/50.
  6. Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272.
  7. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  8. Halabi, Ghina M.; Eid, Mounib El (2015). "Exploring masses and CNO surface abundances of red giant stars". Monthly Notices of the Royal Astronomical Society. 451 (3): 2957. arXiv:1507.01517. Bibcode:2015MNRAS.451.2957H. doi:10.1093/mnras/stv1141.
  9. Tsuji, T. (2008). "Cool luminous stars: The hybrid nature of their infrared spectra". Astronomy and Astrophysics. 489 (3): 1271–1289. arXiv:0807.4387. Bibcode:2008A&A...489.1271T. doi:10.1051/0004-6361:200809869.
  10. Prugniel, Ph.; Vauglin, I.; Koleva, M. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769.
  11. "RZ Ari -- Semi-regular pulsating Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-08-08.
  12. Tabur, V.; et al. (December 2009), "Long-term photometry and periods for 261 nearby pulsating M giants", Monthly Notices of the Royal Astronomical Society, 400 (4): 1945–1961, arXiv:0908.3228, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x.
  13. Eggen, Olin J. (1992). "Asymptotic Giant Branch Stars Near the Sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239.

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