Astronomy:HD 64740
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Puppis |
| Right ascension | 07h 53m 03.63538s[1] |
| Declination | −49° 36′ 46.9530″[1] |
| Apparent magnitude (V) | 4.63[2] |
| Characteristics | |
| Spectral type | B2V[3] |
| U−B color index | −0.92[2] |
| B−V color index | −0.23[2] |
| Variable type | Constant[4] |
| Astrometry | |
| Radial velocity (Rv) | +8.00±4.2[5] km/s |
| Proper motion (μ) | RA: −7.77[1] mas/yr Dec.: +15.16[1] mas/yr |
| Parallax (π) | 4.30 ± 0.15[1] mas |
| Distance | 760 ± 30 ly (233 ± 8 pc) |
| Absolute magnitude (MV) | −2.2±0.1[6] |
| Details | |
| Mass | 9.6 M☉[7] 10.1±0.5[8] M☉ |
| Radius | 4.5±0.7[8] R☉ |
| Luminosity | 5,908[9] L☉ |
| Surface gravity (log g) | 4.01±0.09[6] cgs |
| Temperature | 23,700[9] K |
| Metallicity [Fe/H] | +0.01[10] dex |
| Rotation | 1.33026 d[11] |
| Rotational velocity (v sin i) | 160[12] km/s |
| Age | 12.6+7.4 −2.7[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 64740 is a single[13] star in the southern constellation Puppis, positioned near the line of sight to the Gum Nebula.[4] It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.63.[2] Parallax measurements give a distance estimate of approximately 760 light-years from the Sun,[1] and it is drifting further away with a radial velocity of +8 km/s.[5]
This is a massive B-type main-sequence star with a stellar classification of B2V.[3] It is a magnetic chemically peculiar star of the helium strong variety[6] with weak hydrogen alpha emission.[8] The polar magnetic field strength is 3,700 G.[4] The star is about halfway through its main sequence lifetime with an estimated age of ~13 million years.[8] It is spinning rapidly with an equatorial velocity of about 140±10 km/s, based on a polar inclination angle of 36°±15°,[4] giving it a rotation period of ~1.33 days.[11] The star is radiating over 5,900 times the luminosity of the Sun from its photosphere at an effective temperature of 23,700 K.[9]
Significant X-ray emission has been detected originating from this star, which may be connected to the magnetically-confined stellar wind.[14] The star does not display pulsation behavior, but it does show a magnetically-modulated variation from the wind.[15] Variation of ultraviolet lines of silicon has been detected, which may be due to surface abundance variations.[4] Two patches of helium overabundance are observed near the magnetic poles, which are inclined by about 20° to the star's pole of rotation.[11]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. Vizier catalog entry
- ↑ 2.0 2.1 2.2 2.3 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. Bibcode: 2002yCat.2237....0D.
- ↑ 3.0 3.1 Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. 2. Ann Arbor: Dept. of Astronomy, University of Michigan. Bibcode: 1978mcts.book.....H.
- ↑ 4.0 4.1 4.2 4.3 4.4 Krtička, J. et al. (August 2013). "Ultraviolet and visual flux and line variations of one of the least variable Bp stars HD 64740". Astronomy & Astrophysics 556: 11. doi:10.1051/0004-6361/201221018. A18. Bibcode: 2013A&A...556A..18K.
- ↑ 5.0 5.1 Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G.
- ↑ 6.0 6.1 6.2 Shultz, M. E. et al. (May 2019). "The magnetic early B-type Stars II: stellar atmospheric parameters in the era of Gaia". Monthly Notices of the Royal Astronomical Society 485 (2): 1508–1527. doi:10.1093/mnras/stz416. Bibcode: 2019MNRAS.485.1508S.
- ↑ Tetzlaff, N. et al. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society 410 (1): 190–200. doi:10.1111/j.1365-2966.2010.17434.x. Bibcode: 2011MNRAS.410..190T. Vizier catalog entry
- ↑ 8.0 8.1 8.2 8.3 8.4 Shultz, M. E. et al. (November 2019). "The magnetic early B-type stars - III. A main-sequence magnetic, rotational, and magnetospheric biography". Monthly Notices of the Royal Astronomical Society 490 (1): 274–295. doi:10.1093/mnras/stz2551. Bibcode: 2019MNRAS.490..274S.
- ↑ 9.0 9.1 9.2 Hohle, M. M. et al. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten 331 (4): 349. doi:10.1002/asna.200911355. Bibcode: 2010AN....331..349H. Vizier catalog entry
- ↑ Gontcharov, G. A. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters 38 (12): 771–782. doi:10.1134/S1063773712120031. Bibcode: 2012AstL...38..771G. Vizier catalog entry
- ↑ 11.0 11.1 11.2 Alecian, E.; Peralta, R.; Oksala, M. E.; Neiner, C. (December 2012). "The Magnetism in Massive Stars (MiMeS) project: First HARPSpol discoveries". in Boissier, S.; de Laverny, P.; Nardetto, N. et al.. pp. 401–404. Bibcode: 2012sf2a.conf..401A.
- ↑ Hoffleit, D.; Warren, W. H. (1995). "Bright Star Catalogue". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H 5050. Bibcode: 1995yCat.5050....0H.
- ↑ Chini, R. et al. (2012). "A spectroscopic survey on the multiplicity of high-mass stars". Monthly Notices of the Royal Astronomical Society 424 (3): 1925. doi:10.1111/j.1365-2966.2012.21317.x. Bibcode: 2012MNRAS.424.1925C.
- ↑ Nazé, Yaël et al. (November 2014). "X-Ray Emission from Magnetic Massive Stars". The Astrophysical Journal Supplement 215 (1): 20. doi:10.1088/0067-0049/215/1/10. 10. Bibcode: 2014ApJS..215...10N.
- ↑ Telting, J. H. et al. (2006). "A high-resolution spectroscopy survey of β Cephei pulsations in bright stars". Astronomy and Astrophysics 452 (3): 945. doi:10.1051/0004-6361:20054730. Bibcode: 2006A&A...452..945T.
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