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HD 64568

HD 64568
Location of HD 64568 (circled)
Observation data
Epoch J2000.0[1]      Equinox J2000.0[1]
Constellation Puppis
Right ascension 07h 53m 38.20519s
Declination −26° 14′ 02.5981″
Apparent magnitude (V) 9.39[2]
Characteristics
Evolutionary stage Main-sequence star
Spectral type O3V((f*))z[3]
U−B color index −0.86[2]
B−V color index 0.11[2]
J−H color index 0.001[4]
J−K color index 0.008[4]
Astrometry
Radial velocity (Rv)87.1±5.7[5] km/s
Proper motion (μ) RA: −0.535[1] mas/yr
Dec.: 4.115[1] mas/yr
Parallax (π)0.2241 ± 0.0177 mas[1]
Distance15,000 ± 1,000 ly
(4,500 ± 400 pc)
Details[5]
Mass57[6] M☉
Radius14±2[6] R☉
Luminosity500000+290000
−180000[6] L☉
Surface gravity (log g)3.91±0.08 cgs
Temperature44900±1700 K
Rotational velocity (v sin i)≤117±13 km/s
Other designations
CD−25° 5228, CPD−25° 3039, Gaia DR2 5602033390154015744, HD 64568, HIP 38548, SAO 174748, PPM 253404, TIC 128808726, TYC 6557-214-1, GSC 06557-00214, 2MASS J07533820-2614025, DENIS J075338.2-261402, NGC 2467 77[7]
Database references
SIMBADdata

HD 64568 is a massive solitary[8] star in the southern constellation of Puppis. With an apparent magnitude of 9.39, it is too faint to be seen by the naked eye, but can barely be observed by binoculars, appearing as a blue-hued dot of light. It is located approximately 4,500 parsecs (15,000 light-years) distant according to Gaia EDR3 parallax measurements.

Properties

Image of NGC 2467
HD 64568
HD 64568
Image of NGC 2467 from ESO. HD 64568 (circled) is in the top right.

HD 64568 belongs to an OB association named Puppis OB2, which is part of the star-forming region NGC 2467. It is one of the ionizing stars of the H II region Sh 2-311.[6]

This is a very early O-type main-sequence star that is among the most massive stars, weighing 57 times the mass of the Sun, but has a comparatively modest radius of 14 R☉. It radiates roughly 500,000 times the luminosity of the Sun from its photosphere at an effective temperature of 44,900 K (44,600 °C; 80,400 °F). It is losing mass to stellar winds, but the rate at which this occurs is highly uncertain, with two models yielding values of 5.6±5.0×10−7 M☉/yr and 2.3×10−6 M☉/yr.[6]

In 1982, it was given the spectral type O3V((f*)), becoming the first object of its kind. The ((f*)) suffix signifies the presence of weak N IV (N3+) 4058 Å emission line and N V (N4+) absorption lines, the lack of any N III (N2+) emission, along with the strong He II (He+) 4686 Å absorption.[9] Radial velocity variations were discovered in 1986, which, at the time, was theorized to be either caused by an unseen binary companion or atmospheric instabilities seen in massive stars.[10] The latter theory was confirmed to be true by Markova (2011) as there was no evidence for a secondary object, and the variations are now thought to be the result of stellar pulsations and/or stellar wind variations. The same study also corroborated the O3V((f*)) classification.[8] Sota et al. (2014) updated the spectral type to O3V((f*))z, with the added "z" suffix to indicate that the 4686 Å helium line is abnormally strong.[3]

References

  1. ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. ^ a b c Lodén, L. O. (1966). "A study of NGC 2467 an dthe association Pup I". Arkiv för Astronomii. 4: 65-72. Bibcode:1966ArA.....4...65L.
  3. ^ a b Sota, A.; Apellániz, J. Maíz; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J. (25 February 2014). "THE GALACTIC O-STAR SPECTROSCOPIC SURVEY (GOSSS). II. BRIGHT SOUTHERN STARS". The Astrophysical Journal Supplement Series. 211 (1): 10. arXiv:1312.6222. doi:10.1088/0067-0049/211/1/10. ISSN 0067-0049.
  4. ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  5. ^ a b Williams, S. J.; Gies, D. R.; Hillwig, T. C.; McSwain, M. V.; Huang, W. (1 November 2011). "RADIAL VELOCITIES OF GALACTIC O-TYPE STARS. I. SHORT-TERM CONSTANT VELOCITY STARS". The Astronomical Journal. 142 (5): 146. doi:10.1088/0004-6256/142/5/146. ISSN 0004-6256.
  6. ^ a b c d e Garcia, Miriam; Bianchi, Luciana (2004). "The Effective Temperatures of Hot Stars. II. The Early‐O Types". The Astrophysical Journal. 606 (1): 497–513. doi:10.1086/383002. ISSN 0004-637X.
  7. ^ "HD 64568". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 6 December 2024.
  8. ^ a b Markova, N.; Puls, J.; Scuderi, S.; Simón-Díaz, S.; Herrero, A. (2011). "Spectroscopic and physical parameters of Galactic O-type stars: I. Effects of rotation and spectral resolving power in the spectral classification of dwarfs and giants". Astronomy & Astrophysics. 530: A11. doi:10.1051/0004-6361/201015956. ISSN 0004-6361.
  9. ^ Walborn, N. R. (1982). "The O3 stars". The Astrophysical Journal. 254: L15. doi:10.1086/183747. ISSN 0004-637X.
  10. ^ Solivella, G. R.; Niemela, V. S. (February 1986). "A radial velocity study of two early O stars". Revista Mexicana de Astronomia y Astrofisica. 12: 188. Bibcode:1986RMxAA..12..188S.
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