HR 5401

HR 5401 is a possible astrometric binary[7] star system in the southern constellation of Lupus. With an apparent visual magnitude of 5.83,[2] it is just visible to the naked eye under good seeing conditions. The distance to HR 5401 can be estimated from its annual parallax shift of 15.9 mas,[1] yielding a range of 205 light years. It is moving closer to Earth with a heliocentric radial velocity of −30 km/s,[4] and is expected to come within 161 ly in ~524,000 years.[2]

HR 5401
Observation data
Epoch J2000      Equinox J2000
Constellation Lupus
Right ascension 14h 27m 12.18204s[1]
Declination −46° 08′ 58.1316″[1]
Apparent magnitude (V) 5.83[2]
Characteristics
Spectral type A1m A5/7-F2[3]
B−V color index 0.311±0.004[2]
Astrometry
Radial velocity (Rv)−30.0±3.8[4] km/s
Proper motion (μ) RA: −168.816[1] mas/yr
Dec.: −82.297[1] mas/yr
Parallax (π)15.8815 ± 0.2813[1] mas
Distance205 ± 4 ly
(63 ± 1 pc)
Absolute magnitude (MV)2.01[2]
Details
Luminosity13.01[2] L☉
Surface gravity (log g)3.92[5] cgs
Temperature7,300[5] K
Metallicity [Fe/H]0.2[5] dex
Other designations
CD−45° 9188, HD 126504, HIP 70663, HR 5401, SAO 224929, WDS WDS J14272-4608A[6]
Database references
SIMBADdata

This is an Am star[8] with a stellar classification of A1m A5/7-F2.[3] Lu (1991) lists it as a likely dwarf barium star.[9] It is radiating 13[2] times the Sun's luminosity from its photosphere at an effective temperature of 7,300 K.[5] This system is a source of X-ray emission which may be coming from the companion.[8]

HR 5401 has two visual companions. Component B is a magnitude 11.50 star at an angular separation of 33.1″ along a position angle (PA) of 114°, as of 1999. The second companion, designated component C, is magnitude 11.16 with a separation of 27.20″ at a PA of 164°, as of 2000.[10]

References
  1. 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.
  2. 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.
  3. Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. North, P.; et al. (January 1994), "The nature of the F STR lambda 4077 stars. 3: Spectroscopy of the barium dwarfs and other CP stars", Astronomy and Astrophysics, 281 (3): 775–796, Bibcode:1994A&A...281..775N.
  6. "HD 126504". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-30.
  7. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  8. Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677–684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429.
  9. Lu, Phillip K. (1991), "Taxonomy of barium stars", Astronomical Journal, 101: 2229, Bibcode:1991AJ....101.2229L, doi:10.1086/115845.
  10. Mason, B. D.; et al. (2008), Washington Visual Double Star Catalog, 2006.5 (WDS), U. S. Naval Observatory, Washington D.C., Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
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