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.

Rho2 Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
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 mas[1]
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

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  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, S2CID 18759600.
  2. ^ a b c 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. ^ a b Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 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, S2CID 119231169.
  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, S2CID 119257644.
  6. ^ a b 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, S2CID 118665352.
  7. ^ "rho02 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-05.{{cite web}}: CS1 maint: postscript (link)
  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.