1 Lupi

1 Lupi is a solitary[11] giant star in the southern constellation of Lupus. It has the Bayer designation i Lupi; 1 Lupi is the Flamsteed designation. The apparent visual magnitude is 4.90,[2] which indicates it is faintly visible to the naked eye. Based on parallax measurements, this star is approximately 1,800 light-years from the Sun.[1] It is moving closer to the Earth with a heliocentric radial velocity of −23 km/s.[6]

This article is about i Lupi (1 Lupi). It is not to be confused with ι (iota) Lupi.
1 Lupi
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lupus
Right ascension 15h 14m 37.32104s[1]
Declination −31° 31′ 08.8434″[1]
Apparent magnitude (V) 4.90[2]
Characteristics
Spectral type F1 III[3] or F0 Ib-II[4]
U−B color index +0.26[2]
B−V color index 0.37[5]
Astrometry
Radial velocity (Rv)−22.80[6] km/s
Proper motion (μ) RA: −9.873[1] mas/yr
Dec.: –0.892[1] mas/yr
Parallax (π)1.8055 ± 0.1876 mas[1]
Distanceapprox. 1,800 ly
(approx. 550 pc)
Absolute magnitude (MV)−3.93[7]
Details
Mass6.9±0.1[8] M☉
Radius41.3+2.2
−1.7[1] R☉
Luminosity2,900[9] L☉
Temperature6,867[6] K
Rotational velocity (v sin i)3.9±0.2[5] km/s
Age47.1±3.8[8] Myr
Other designations
i Lup, 1 Lup, CD−31°11813, HD 135153, HIP 74604, HR 5660, SAO 206445[10]
Database references
SIMBADdata

Houk (1978) assigned the spectral classification of this star as F1III,[3] which suggests it is an F-type (yellow-white) star that has evolved away from the main sequence and expanded into a giant. However, Gray et al. (2001) found a class of F0 Ib-II,[4] matching a supergiant/bright giant star. It has a mass around seven times that of the Sun[8] and has expanded to 41[1] times the Sun's radius. The star is radiating 2,900[9] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 6,867 K.[6] The estimated age of the star is around 47 million years.[8]

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. Gaia DR2 record for this source at VizieR.
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
  3. Houk, N. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  4. Gray, R. O.; et al. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148–2158, Bibcode:2001AJ....121.2148G, doi:10.1086/319956.
  5. Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID 53666672.
  6. Gontcharov, G. A. (November 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.
  7. 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.
  8. Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
  9. 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.
  10. "i Lup -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-03-07.
  11. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
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