Phi1 Lupi

Phi1 Lupi is a solitary[10] star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 3.58.[2] Based upon an annual parallax shift of 11.86 mas as seen from Earth, it is located around 275 light years from the Sun. The star is drifting closer with a radial velocity of −29 km/s.[5] It has an absolute magnitude of −1.55.[6]

For other stars with this Bayer designation, see φ Lupi.
Phi1 Lupi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lupus
Right ascension  15h 21m 48.36967s[1]
Declination −36° 15′ 40.9525″[1]
Apparent magnitude (V) 3.58[2]
Characteristics
Spectral type K5 III[3]
U−B color index +1.85[2]
B−V color index +1.534±0.005[4]
Astrometry
Radial velocity (Rv)−29.4±0.7[5] km/s
Proper motion (μ) RA: −92.33[1] mas/yr
Dec.: −85.67[1] mas/yr
Parallax (π)11.86 ± 0.16[1] mas
Distance275 ± 4 ly
(84 ± 1 pc)
Absolute magnitude (MV)−1.55[6]
Details
Radius40[7] R☉
Luminosity711.28[4] L☉
Temperature3,894±59[8] K
Other designations
φ1 Lup, CD−35°10236, FK5 566, HD 136422, HIP 75177, HR 5705, SAO 206552[9]
Database references
SIMBADdata

This is an evolved K-type giant star with a stellar classification of K5 III,[3] which means it has used up its core hydrogen and has expanded. At present it has 40 times the radius of the Sun.[7] It is a variable star of unknown type, with an amplitude of 0.008 in visual magnitude and a period of 4.82 days.[11] The star is radiating 711[4] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,894 K.[8]

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.
  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 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.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, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H.
  4. 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.
  5. 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.
  6. Ginestet, N.; et al. (February 2000), "Magnitudes absolues des étoiles standards MK des types G à M à partir des parallaxes Hipparcos" [The absolute magnitudes of the G to M type MK standards from the Hipparcos parallaxes], Astronomy and Astrophysics Supplement (in French), 142: 13–24, Bibcode:2000A&AS..142...13G, doi:10.1051/aas:2000135.
  7. 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.
  8. Strassmeier, K. G.; Schordan, P. (2000), "A temperature calibration for MK-class III giants from high-resolution spectral line-depth ratios", Astronomische Nachrichten, 321 (5): 277–305, Bibcode:2000AN....321..277S, doi:10.1002/1521-3994(200012)321:5/6<277::AID-ASNA277>3.0.CO;2-H.
  9. "* phi01 Lup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-03-10.
  10. 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.
  11. Koen, Chris; Eyer, Laurent (March 2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331 (1): 45–59, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x.
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