Rho Aquarii
Location of ρ Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 20m 11.91830s[1]
Declination –07° 49′ 15.9742″[1]
Apparent magnitude (V) +5.34[2]
Characteristics
Spectral type B8 IIIp Mn:Hg:[3]
U−B color index –0.358[2]
B−V color index –0.057[2]
Astrometry
Radial velocity (Rv)–9[4] km/s
Proper motion (μ) RA: +13.201[1] mas/yr
Dec.: +0.030[1] mas/yr
Parallax (π)3.7483 ± 0.1608 mas[1]
Distance870 ± 40 ly
(270 ± 10 pc)
Absolute magnitude (MV)−1.78[5]
Orbit[6]
Period (P)220.41±0.10 d
Periastron epoch (T)2,418,548.7±7.4 JD
Semi-amplitude (K1)
(primary)		18.66±2.75 km/s
Details
A
Mass5.00±0.22[7] M☉
Luminosity1,035[7] L☉
Temperature12,593[8] K
Rotational velocity (v sin i)65[3] km/s
Other designations
ρ Aqr, 46 Aquarii, BD–08 5855, HD 211838, HIP 110273, HR 8512, SAO 146023[9]
Database references
SIMBADdata

Rho Aquarii, Latinized from ρ Aquarii, is the Bayer designation for a binary star[8] system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of +5.34.[2] Based upon parallax measurements, this star is at a distance of roughly 870 light-years (270 parsecs) from Earth.[1] It is drifting closer with a radial velocity of –9 km/s.[4] The proximity of this star to the ecliptic means it is subject to lunar occultations.[10]

This is a single-lined spectroscopic binary, with the presence of a companion being revealed by Doppler shifts in the spectrum.[8] An initial orbital solution for the data gives an orbital period of 220.4 days.[6] The primary is a giant star with a stellar classification of B8 IIIp Mn:Hg:.[3] It is a candidate mercury-manganese star, showing a surfeit of these elements in the spectrum.[8] With five times the Sun's mass, this star is radiating 1,035[7] times as much luminosity from its outer atmosphere at an effective temperature of 12,593 K.[8] This heat gives it the blue-white hue of a B-type star.[11] The companion may be a variable star.[12]

References

  1. 1 2 3 4 5 6 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. 1 2 3 4 Cousins, A. W. J. (1984), "Standardization of Broadband Photometry of Equatorial Standards", South African Astronomical Observatory Circulars, 8: 59, Bibcode:1984SAAOC...8...59C.
  3. 1 2 3 Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
  4. 1 2 Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  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. 1 2 Stickland, D. J.; Weatherby, J. (July 1984), "Radial velocities of northern mercury stars", Astronomy and Astrophysics, Supplemental Series, 57: 55–67, Bibcode:1984A&AS...57...55S.
  7. 1 2 3 Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
  8. 1 2 3 4 5 Makaganiuk, V.; et al. (January 2011), "The search for magnetic fields in mercury-manganese stars", Astronomy and Astrophysics, 525: A97, arXiv:1010.3931, Bibcode:2011A&A...525A..97M, doi:10.1051/0004-6361/201015666, S2CID 118860674.
  9. ↑ "* rho Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-04.
  10. ↑ Hilaire, G. (March 1974), "Observations of occultations of stars by the moon", Astronomy and Astrophysics Supplement, 13: 395, Bibcode:1974A&AS...13..395H. See the SAO 146023 entry on p. 402.
  11. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16
  12. ↑ Adelman, S. J.; Young, K. J. (January 2005), "uvby FCAPT photometry of the mCP stars HR 2258, MW Vul, and HR 9017 and the HgMn star 46 ρ Aqr", Astronomy and Astrophysics, 429: 317–322, Bibcode:2005A&A...429..317A, doi:10.1051/0004-6361:20041118.
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