KQ Puppis

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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])
Spectral type M2Iab + B0Ve[4]
U−B color index +0.29[2]
B−V color index +1.41[2]
Variable type LC[3]
Radial velocity (Rv)+22[5] km/s
Proper motion (μ) RA: -6.98[1] mas/yr
Dec.: +4.82[1] mas/yr
Parallax (π)2.12 ± 0.45[1] mas
Distance1,400[6] pc
Period (P)9,752 days
Eccentricity (e)0.46
Inclination (i)60-80°
Cool primary
Mass13-20[6] M
Radius570[6] R
Diameter570[6] D
Luminosity59,800[6] L
Temperature3,662[7] K
Hot secondary
Mass17[6] M
Radius4.35[6] R
Luminosity13,800[6] L
Temperature30,000[6] 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
KQ Puppis is the bright red star on the right, with M47 on the left.

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.

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.[6] 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.[6] It shows small amplitude irregular pulsations, and also some variation associated with the orbital motion.[8] 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.[9]

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.[10] Membership is uncertain as it appears to be more distant than the other stars in the cluster.[11]


  1. 1.0 1.1 1.2 1.3 1.4 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653. arXiv:0708.1752. Bibcode 2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. 2.0 2.1 2.2 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. 3.0 3.1 Samus, N. N.Expression error: Unrecognized word "etal". (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. 4.0 4.1 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. 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 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.
  7. 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: 343. arXiv:1208.2037. Bibcode 2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
  8. 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.
  9. 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: 83. Bibcode 1998ApJS..119...83P. doi:10.1086/313152.
  10. 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.
  11. 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.