Nu Puppis

Nu Puppis (ν Puppis) is a solitary,^[12] blue-hued star in the southern constellation of Puppis. It is the fifth-brightest star in Puppis, with an apparent visual magnitude of 3.17.^[2] Based upon an annual parallax shift of 8.78 mas as seen from Earth,^[1] it is located about 370 light years from the Sun. The system made its closest approach about 3.6 million years ago when it underwent perihelion passage at a distance of roughly 27 light years.^[13]

Nu Puppis

Location of ν Puppis (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Puppis
Right ascension	06h 37m 45.67135s[1]
Declination	−43° 11′ 45.3602″[1]
Apparent magnitude (V)	3.173[2]
Characteristics
Spectral type	B8 III[3]
U−B color index	−0.397[2]
B−V color index	−0.113[2]
Astrometry
Radial velocity (Rv)	+30.9[4] km/s
Proper motion (μ)	RA: −0.44[1] mas/yr Dec.: −3.87[1] mas/yr
Parallax (π)	8.78 ± 0.26 mas[1]
Distance	370 ± 10 ly (114 ± 3 pc)
Absolute magnitude (MV)	−2.11[5]
Details
Radius	4.2[6] R☉
Luminosity	767[7] L☉
Luminosity (bolometric)	1,340[8] L☉
Temperature	12,120[9] K
Rotational velocity (v sin i)	225[10] km/s
Other designations
ν Pup, CPD−43° 946, HD 47670, HIP 31685, HR 2451, SAO 218071[11]
Database references
SIMBAD	data

The star has a stellar classification of B8 III,^[3] matching a B-type giant. Absorption lines in the spectrum are displaying central quasi-emission peaks, indicating this is a Be shell star with a circumstellar disk of heated gas that is being seen edge-on.^[14] ν Puppis is a candidate variable star showing an amplitude of 0.0117 magnitude with a frequency of 0.15292 per day.^[15] It is spinning rapidly with a projected rotational velocity of 225 km/s. This rotation is giving the star an oblate shape, with the equator being 31% larger than the poles.^[10] It is radiating (after allowance for ultraviolet radiation) 1,340^[8] times the Sun's luminosity from its photosphere at an effective temperature of 12,120 K.^[9]

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. Cousins, A. W. J. (1973), "Revised zero points and UBV photometry of stars in the Harvard E and F regions", Memoirs of the Royal Astronomical Society, 77: 223–236, Bibcode:1973MmRAS..77..223C.
3. Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
4. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 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.
5. 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.
6. Pasinetti Fracassini, L. E.; et al. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy & Astrophysics, 367 (3rd ed.): 521–24, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
7. 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.
8. Kaler, James B. (March 28, 2008), "NU PUP (Nu Puppis)", Stars, University of Illinois.
9. Soubiran, C.; et al. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
10. Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.
11. "nu. Pup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-19.{{cite web}}: CS1 maint: postscript (link)
12. 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.
13. Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics, 575: 13, arXiv:1412.3648, Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, S2CID 59039482, A35.
14. Rivinius, Th.; et al. (August 1999), "Central quasi-emission peaks in shell spectra and the rotation of disks of Be stars", Astronomy and Astrophysics, 348: 831–842, Bibcode:1999A&A...348..831R.
15. Koen, Chris; Eyer, Laurent (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, S2CID 10505995.