Rho Puppis

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Rho Puppis
Diagram showing star positions and boundaries of the Puppis constellation and its surroundings
Cercle rouge 100%.svg

Location of ρ Puppis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Puppis
Right ascension 08h 07m 32.64882s[1]
Declination −24° 18′ 15.5679″[1]
Apparent magnitude (V) 2.78[2]
Spectral type F2mF5IIp[3]
U−B color index +0.17[2]
B−V color index +0.40[2]
Variable type δ Sct[4]
Radial velocity (Rv) +46.1[5] km/s
Proper motion (μ) RA: –83.35[1] mas/yr
Dec.: +46.23[1] mas/yr
Parallax (π) 51.33 ± 0.15[1] mas
Distance 63.5 ± 0.2 ly
(19.48 ± 0.06 pc)
Mass 1.85[6] M
Radius 3.41[3] R
Luminosity 22[6] L
Surface gravity (log g) 3.70[7] cgs
Temperature 6,920[8] K
Metallicity [Fe/H] 0.35[7] dex
Rotational velocity (v sin i) 15[9] km/s
Age 2[10] Gyr
Other designations
ρ Puppis, ρ Pup, Rho Pup, 15 Puppis, CPD−23  3368, FK5 308, HD 67523, HIP 39757, HR 3185, SAO 175217.[11]

Rho Puppis (Rho Pup, ρ Puppis, ρ Pup) is a star in the southern constellation of Puppis, which according to British astronomy author Patrick Moore, has the traditional name Turais, which is shared by Iota Carinae.[12] With an average apparent visual magnitude of 2.78,[2] it is the third brightest member of this generally faint constellation. Based upon parallax measurements made during the Hipparcos mission, Rho Puppis is located at a distance of 63.5 light-years (19.5 parsecs) from Earth.[1] At present it is moving away from the Sun with a radial velocity of +46.1 km s−1. The closest approach occurred about 394,000 years ago when Rho Puppis came within roughly 11.6 ly (3.6 pc) of the Solar System; about the same distance as Procyon in the present era.[13]

The variability of this star was announced in 1956 by American astronomer Olin J. Eggen.[4] It was determined to be a Delta Scuti-type variable star, making it one of the first stars of that type to be identified. Photometric observations dating back to 1946 provide a lengthy record of its pattern of pulsation; it undergoes periodic pulsations with a single period of 0.14088143(3) days,[14] or 7.1 cycles per day. During each cycle, the star's magnitude varies with an amplitude of 0.15 and the radial velocity varies by 10 km s−1. The peak brightness occurs 28.8 minutes following the minimum radial velocity.[4] The outer atmosphere's effective temperature of 6,920 K[8] is one of the lowest known for a Delta Scuti variable.[4]

Rho Puppis has an estimated age of about 2 billion years[10] and it has 3.4[3] times the Sun's radius. It has a stellar classification of F2mF5IIp,[3] which matches the spectrum of an F-type bright giant star. It shows stronger than normal absorption lines of metals—a term astronomers use for any element other than hydrogen and helium. The 'p' suffix indicates chemical peculiarities that mark it as a cooler temperature Am star.[15] Most such stars are found in binary star systems,[16] but this appears to be an exception as no companion has been discovered.[10][17] Evolved stars that show this combination of Delta Scuti variability with Am-like peculiarities of abundance have come to be known as ρ Pup stars.[18] The star's metallicity is more than double that in the Sun.[7]

This star shows an excess emission of infrared radiation, suggesting that there is a circumstellar disk of dust orbiting this star. The mean temperature of the emission is 85 K, corresponding to an orbital separation from the host star of 50 AU.[3][10]


  1. ^ a b c d e f van Leeuwen, F. (November 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. ^ a b c d Bookmeyer, B. B.; et al. (August 1977), "Photoelectric UBV observations of RR Lyrae variable stars. Second list", Revista Mexicana de Astronomia y Astrofisica 2: 235–258, Bibcode:1977RMxAA...2..235B 
  3. ^ a b c d e Rhee, Joseph H.; et al. (May 2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal 660 (2): 1556–1571, arXiv:astro-ph/0609555, Bibcode:2007ApJ...660.1556R, doi:10.1086/509912 
  4. ^ a b c d Mathias, P.; et al. (November 1997), "A spectroscopic study of the delta Scuti star rho Puppis", Astronomy and Astrophysics 327: 1077–1086, Bibcode:1997A&A...327.1077M 
  5. ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E 
  6. ^ a b Kaler, James B. (September 5, 2008), "TUREIS (Rho Puppis)", Stars (University of Illinois), retrieved 2012-02-25 
  7. ^ a b c Burkhart, C.; Coupry, M. F. (September 1991), "The A and Am-Fm stars. I - The abundances of Li, Al, Si, and Fe", Astronomy and Astrophysics 249 (1): 205–216, Bibcode:1991A&A...249..205B 
  8. ^ a b Burkhart, C.; et al. (January 2005), "The field Am and ρ Puppis-like stars: Lithium and heavier elements", Astronomy and Astrophysics 429: 1043–1049, Bibcode:2005A&A...429.1043B, doi:10.1051/0004-6361:20040467 
  9. ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago 239 (1). Bibcode:1970CoAsi.239....1B. 
  10. ^ a b c d Rodriguez, David R.; Zuckerman, B. (February 2012), "Binaries among Debris Disk Stars", The Astrophysical Journal 745 (2): 147, arXiv:1111.5618, Bibcode:2012ApJ...745..147R, doi:10.1088/0004-637X/745/2/147 
  11. ^ "rho Pup -- Variable Star of delta Sct type", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), retrieved 2012-01-25 
  12. ^ The observer's year: 366 nights of the universe, Practical Astronomy (2nd ed.), Springer, 2005, p. 346, ISBN 1-85233-884-9 
  13. ^ García-Sánchez, J.; et al. (November 2001), "Stellar encounters with the solar system", Astronomy and Astrophysics 379: 634–659, Bibcode:2001A&A...379..634G, doi:10.1051/0004-6361:20011330 
  14. ^ Moon, T.; van Antwerpen, C. (June 2009), "Period Changes in δ Scuti Stars: ρ Puppis", The Journal of the American Association of Variable Star Observers 37 (1): 3–14, Bibcode:2009JAVSO..37....3M 
  15. ^ McGahee, Courtney; Gray, R. O. (January 2010), "Chemical Abundance Analysis of Rho Puppis Stars", Bulletin of the American Astronomical Society 42: 339, Bibcode:2010AAS...21542520M 
  16. ^ Netopil, M.; et al. (November 2008), "Chemically peculiar stars and their temperature calibration", Astronomy and Astrophysics 491 (2): 545–554, arXiv:0809.5131, Bibcode:2008A&A...491..545N, doi:10.1051/0004-6361:200810325 
  17. ^ 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. 
  18. ^ Kochukhov, O. (March 2009), "Asteroseismology of chemically peculiar stars", Communications in Asteroseismology 159: 61–70, arXiv:0812.0374, Bibcode:2009CoAst.159...61K, doi:10.1553/cia159s61