Astronomy:Rho2 Arietis

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Short description: Star in the constellation Aries


ρ2 Arietis
Aries constellation map.svg
Red circle.svg
Location of ρ2 Arietis (circled)
Observation data
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 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.

A visual band light curve for Rho2 Arietis, plotted from data presented in Tabur et al. (2009)[12]

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. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 Lee, T. A. (October 1970), "Photometry of high-luminosity M-type stars", Astrophysical Journal 162: 217, doi:10.1086/150648, Bibcode1970ApJ...162..217L. 
  3. 3.0 3.1 3.2 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, doi:10.1146/annurev.aa.11.090173.000333, Bibcode1973ARA&A..11...29M. 
  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, doi:10.1051/0004-6361:20041272, Bibcode2005A&A...430..165F. 
  7. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  8. 8.0 8.1 8.2 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. doi:10.1093/mnras/stv1141. Bibcode2015MNRAS.451.2957H. 
  9. Tsuji, T. (2008). "Cool luminous stars: The hybrid nature of their infrared spectra". Astronomy and Astrophysics 489 (3): 1271–1289. doi:10.1051/0004-6361:200809869. Bibcode2008A&A...489.1271T. 
  10. 10.0 10.1 Prugniel, Ph.; Vauglin, I.; Koleva, M. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics 531: A165, doi:10.1051/0004-6361/201116769, Bibcode2011A&A...531A.165P. 
  11. "RZ Ari -- Semi-regular pulsating Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+18191, retrieved 2012-08-08. 
  12. 12.0 12.1 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, doi:10.1111/j.1365-2966.2009.15588.x, Bibcode2009MNRAS.400.1945T. 
  13. Eggen, Olin J. (1992). "Asymptotic Giant Branch Stars Near the Sun". The Astronomical Journal 104: 275. doi:10.1086/116239. Bibcode1992AJ....104..275E. 

Coordinates: Sky map 02h 55m 48.4978s, +18° 19′ 53.903″