Phi1 Lupi

Phi1 Lupi is a solitary[9] 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.

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 +1.53[2]
Astrometry
Radial velocity (Rv)−29.4±0.7[4] 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[5]
Details
Radius52[6] R☉
Temperature3,894±59[7] K
Other designations
φ1 Lup, CD−35° 10236, FK5 566, HD 136422, HIP 75177, HR 5705, SAO 206552.[8]
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. The measured angular diameter, after correction for limb darkening, is 5.69±0.07 mas.[10] At the estimated distance of Phi1 Lupi, this yields a physical size of about 52 times the radius of the Sun.[6] 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]

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 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.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. 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. 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.
  6. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  7. 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.
  8. "* phi01 Lup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-03-10.
  9. 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.
  10. Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
  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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