Xi1 Lupi

Xi1 Lupi (ξ1 Lup, ξ1 Lupi) is a probable binary star[8] in the southern constellation of Lupus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.1,[2] and forms a visual double star with Xi2 Lupi. Based upon an annual parallax shift of 23.60[1] mas as seen from Earth, it is located around 140 light years from the Sun. It is a member of the Upper Scorpius sub-group of the nearby Sco OB2 association.[9]

For other stars with this Bayer designation, see ξ Lupi.
Xi1 Lupi
The location of Xi1 Lupi (ξ1) in the constellation of Lupus (shown as a red target's bullseye).
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lupus
Right ascension 15h 56m 53.49808s[1]
Declination −33° 57′ 58.0129″[1]
Apparent magnitude (V) 5.114[2]
Characteristics
Spectral type A3 V[3]
U−B color index 0.069[2]
B−V color index 0.116[2]
Astrometry
Radial velocity (Rv)−10.0±4.2[4] km/s
Proper motion (μ) RA: +23.27[1] mas/yr
Dec.: −37.85[1] mas/yr
Parallax (π)23.60 ± 3.48[1] mas
Distanceapprox. 140 ly
(approx. 42 pc)
Details
Mass2.01[5] M☉
Luminosity12[6] L☉
Surface gravity (log g)4.14±0.14[5] cgs
Temperature9,206±313[5] K
Rotational velocity (v sin i)78[5] km/s
Age237[5] Myr
Other designations
ξ1 Lup, CD−33° 10826A, HD 142629, HIP 78105, HR 5925, SAO 207144, WDS J15569-3358A.[7]
Database references
SIMBADdata

This star shows periodic radial velocity variations that can be best explained as a spectroscopic binary system.[8] The visible component is an A-type main sequence star with a stellar classification of A3 V.[3] It has twice[5] the mass of the Sun and shines with about 12[6] times the Sun's luminosity from its outer atmosphere at an effective temperature of 9,206 K.[5] The star is an estimated 237 million years old and is spinning with a projected rotational velocity of 78 km/s.[5]

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, S2CID 18759600.
  2. Slawson, Robert W.; Hill, Robert J.; Landstreet, John D. (September 1992), "A homogeneous catalog of new UBV and H-beta photometry of B- and A-type stars in and around the Scorpius-Centaurus OB association", Astrophysical Journal Supplement Series, 82 (1): 117–144, Bibcode:1992ApJS...82..117S, doi:10.1086/191711.
  3. Levato, H. (January 1975), "Rotational velocities and spectral types for a sample of binary systems", Astronomy and Astrophysics Supplement Series, 19: 91–99, Bibcode:1975A&AS...19...91L.
  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, S2CID 59451347, A61.
  5. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
  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, S2CID 118665352.
  7. "ksi01 Lup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-03-08.
  8. Antonello, E.; et al. (January 2006), "Probable nonradial g-mode pulsation in early A-type stars", Astronomy and Astrophysics, 445 (1): L15–L18, arXiv:astro-ph/0511491, Bibcode:2006A&A...445L..15A, doi:10.1051/0004-6361:200500216, S2CID 15557098.
  9. Brown, A. G. A.; Verschueren, W. (March 1997), "High S/N Echelle spectroscopy in young stellar groups. II. Rotational velocities of early-type stars in SCO OB2", Astronomy and Astrophysics, 319: 811–838, arXiv:astro-ph/9608089, Bibcode:1997A&A...319..811B.
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