KQ Puppis

KQ Puppis (KQ Pup) is a spectroscopic binary variable star in the constellation Puppis. A red supergiant star and a hot main sequence star orbit each other every 9,742 days. Its apparent magnitude varies between 4.82 and 5.17.

KQ Puppis
Observation data
Epoch J2000      Equinox J2000
Constellation Puppis
Right ascension 07h 33m 47.96383s[1]
Declination −14° 31′ 26.0026″[1]
Apparent magnitude (V) +4.97[2] (4.82 - 5.17[3])
Characteristics
Spectral type M2Iab + B0Ve[4]
U−B color index +0.29[2]
B−V color index +1.41[2]
Variable type LC[3]
Astrometry
Radial velocity (Rv)+22[5] km/s
Proper motion (μ) RA: -6.584[6] mas/yr
Dec.: +3.34[6] mas/yr
Parallax (π)1.4894 ± 0.2296[6] mas
Distanceapprox. 2,200 ly
(approx. 700 pc)
Orbit[7]
Period (P)9,752 days
Eccentricity (e)0.46
Inclination (i)60-80°
Details
Cool primary
Mass13-20[7] M☉
Radius415[8] R☉
Luminosity26,500 - 28,100[8] L☉
Temperature3,662[9][8] K
Hot secondary
Mass17[7] M☉
Radius4.35[7] R☉
Luminosity13,800[7] L☉
Temperature30,000[7] K
Other designations
KQ Pup, BD−14°1971, HIP 36773, HR 2902, NGC 2422 9, SAO 153072
Primary: HD 60414
Secondary: HD 60415
Database references
SIMBADdata
KQ Puppis is the bright red star on the right, with M47 on the left.

The KQ Puppis system consists of a fairly typical M2 supergiant, in orbit with a hotter less luminous star. The hotter star is surrounded by a disc of material being transferred from the cool supergiant. This type of binary is referred to a VV Cephei system, although in this case there are no eclipses of either star.[7] A portion of the disc does appear to be eclipsed and this is detected as a strong drop in far-ultraviolet radiation for about a third of the orbit.[4]

The red supergiant primary star has been compared to Betelgeuse.[7] It shows small amplitude irregular pulsations, and also some variation associated with the orbital motion.[10] The nature of the secondary is less certain. The spectrum shows high excitation features that would indicate an early B or hotter spectral type, but these may be associated with the disc rather than that star itself. Other studies have found a spectrum similar to an A supergiant, but this is thought to be an artefact of a B-type shell star.[11]

KQ Puppis has been catalogued as an outlying member of the open cluster Messier 47 (NGC 2422) and would be the brightest member of that cluster.[12] Membership is uncertain as it appears to be more distant than the other stars in the cluster.[13]

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. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
  3. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: 02025. Bibcode:2009yCat....102025S.
  4. González-Riestra, R.; Rossi, C.; Viotti, R. F. (2003). "First far-UV observations of KQ Puppis with FUSE". Astronomy and Astrophysics. 399 (2): 681. Bibcode:2003A&A...399..681G. doi:10.1051/0004-6361:20021830.
  5. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington: 0. Bibcode:1953GCRV..C......0W.
  6. 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.
  7. Rossi, C.; Altamore, A.; Baratta, G. B.; Friedjung, M.; Viotti, R. (1992). "The spectrum of the VV Cephei star KQ Puppis (Boss 1985). III - A possible model". Astronomy and Astrophysics. 256: 133. Bibcode:1992A&A...256..133R.
  8. Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
  9. McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. S2CID 118665352.
  10. Viotti, R.; Rossi, C.; Muratorio, G. (1998). "Optical and near-IR observations of variable stars with AURELIE". Astronomy and Astrophysics Supplement. 128 (3): 447. Bibcode:1998A&AS..128..447V. doi:10.1051/aas:1998156.
  11. Parsons, Sidney B.; Ake, Thomas B. (1998). "Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample". The Astrophysical Journal Supplement Series. 119 (1): 83. Bibcode:1998ApJS..119...83P. doi:10.1086/313152.
  12. Van Schewick, H. (1966). "Untersuchungen uber die Eigenbewegungen von Sternhaufen. XII. NGC 2422, NGC 2423, NGC 7209 und An. Bakhatova I im Sel. Area 40". Veroeff. Univ. Sternw. Bonn. 74: 1. Bibcode:1966VeBon..74....1V.
  13. Baumgardt, H.; Dettbarn, C.; Wielen, R. (2000). "Absolute proper motions of open clusters. I. Observational data". Astronomy and Astrophysics Supplement. 146 (2): 251. arXiv:astro-ph/0010306. Bibcode:2000A&AS..146..251B. doi:10.1051/aas:2000362. S2CID 7180188.
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