Rho2 Sagittarii

Rho2 Sagittarii (ρ2 Sagittarii) is a star in the zodiac constellation of Sagittarius. With an apparent visual magnitude of +5.87,[2] it is near the lower limit of stars that can be seen with the naked eye. Based upon an annual parallax shift of 9.82 mas as seen from Earth,[1] it is located around 330 light years from the Sun.

For other stars with this Bayer designation, see ρ Sagittarii.
Rho2 Sagittarii
Location of ρ2 Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension  19h 21m 50.89574s[1]
Declination −18° 18′ 30.1996″[1]
Apparent magnitude (V) +5.87[2]
Characteristics
Spectral type K0 III[3]
B−V color index +1.06[2]
Astrometry
Radial velocity (Rv)−12.7±2.9[4] km/s
Proper motion (μ) RA: +102.72[1] mas/yr
Dec.: −93.20[1] mas/yr
Parallax (π)9.82 ± 0.40[1] mas
Distance330 ± 10 ly
(102 ± 4 pc)
Absolute magnitude (MV)+0.80[5]
Details
Luminosity60.4[6] L☉
Temperature4,721[6] K
Other designations
ρ2 Sgr, 45 Sgr, BD−18° 5325, HD 181645, HIP 95188, HR 7344, SAO 162521[7]
Database references
SIMBADdata

This is an evolved K-type giant star with a stellar classification of K0 III.[3] As a result of a 1997 lunar occultation, a companion star was discovered at an angular separation of 21 mas. It appears to be an A-type main sequence star with a class of around A5. This companion was not detected during prior occultations by the Moon.[8]

References
  1. 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. Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa, 27: 11, Bibcode:1968MNSSA..27...11C.
  3. Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  4. Gontcharov, G. A. (2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065.
  5. 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.
  6. McDonald, I.; et al. (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.
  7. "rho02 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-05.
  8. Richichi, A.; et al. (October 1999), "New binary stars discovered by lunar occultations. IV", Astronomy and Astrophysics, 350: 491–496, Bibcode:1999A&A...350..491R.
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