HD 149382
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16h 34m 23.33337s[1] |
| Declination | −04° 00′ 52.0301″[1] |
| Apparent magnitude (V) | 8.943[2] |
| Characteristics | |
| Spectral type | B5 VI[3] |
| U−B color index | −1.143[2] |
| B−V color index | −0.282[2] |
| V−R color index | −0.127[2] |
| R−I color index | −0.135[2] |
| Astrometry | |
| Radial velocity (Rv) | +3[4] km/s |
| Proper motion (μ) | RA: −6.234[1] mas/yr Dec.: −5.780[1] mas/yr |
| Parallax (π) | 13.2407±0.0567 mas[1] |
| Distance | 246 ± 1 ly (75.5 ± 0.3 pc) |
| Details | |
| Mass | 0.29 – 0.53[5] M☉ |
| Radius | 0.143[6] R☉ |
| Luminosity | 25.2[6] L☉ |
| Surface gravity (log g) | 5.80±0.05[5] cgs |
| Temperature | 35,500±500[5] K |
| Metallicity [Fe/H] | −1.30[3] dex |
| Rotational velocity (v sin i) | 4.9±1.4[5] km/s |
| Other designations | |
| BD−03°3967, HD 149382, HIP 81145, SAO 141250[7] | |
| Database references | |
| SIMBAD | data |
HD 149382 is a hot subdwarf star in the constellation of Ophiuchus with an apparent visual magnitude of 8.943.[2] This is too faint to be seen with the naked eye even under ideal conditions, although it can be viewed with a small telescope.[8] Based upon parallax measurements, this star is located at a distance of about 246 light-years (75.5 parsecs) from the Earth.
This is the brightest known B-type subdwarf star with a stellar classification of B5 VI. It is generating energy through the thermonuclear fusion of helium at its core (triple-alpha process).[3] The effective temperature of the star's outer envelope is about 35,500 K, giving it the characteristic blue-white hue of a B-type star. Although only about one seventh the diameter of the Sun, it radiates about 25 times as much due to its high temperature. HD 149382 has a visual companion located at an angular separation of 1 arcsecond.[9]
In 2009, a substellar companion, perhaps even a superjovian planet, was announced orbiting the star. This candidate object was estimated to have 8 to 23 times the mass of Jupiter.[5] In 2011, this discovery was thrown into doubt when an independent team of astronomers were unable to confirm the detection. Their observations rule out a companion with a mass greater than Jupiter orbiting with a period of less than 28 days.[9]
See also
[edit]References
[edit]- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f Landolt, Arlo U. (May 2009). "UBVRI Photometric Standard Stars Around the Celestial Equator: Updates and Additions". The Astronomical Journal. 137 (5): 4186–4269. arXiv:0904.0638. Bibcode:2009AJ....137.4186L. doi:10.1088/0004-6256/137/5/4186. S2CID 118627330. See table II.
- ^ a b c Cenarro, A. J.; et al. (January 2007). "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters". Monthly Notices of the Royal Astronomical Society. 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. S2CID 119428437.
- ^ Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
- ^ a b c d e Geier, S.; et al. (September 2009). "Discovery of a Close Substellar Companion to the Hot Subdwarf Star HD 149382—The Decisive Influence of Substellar Objects on Late Stellar Evolution". The Astrophysical Journal Letters. 702 (1): L96 – L99. arXiv:0908.1025. Bibcode:2009ApJ...702L..96G. doi:10.1088/0004-637X/702/1/L96. S2CID 119282460.
- ^ a b Stassun, Keivan G.; et al. (September 2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal. 156 (3): 102. arXiv:1706.00495. Bibcode:2018AJ....156..102S. doi:10.3847/1538-3881/aad050. ISSN 0004-6256.
- ^ "HD 149382 -- Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-10-06.
- ^ Sherrod, P. Clay; Koed, Thomas L. (2003). A Complete Manual of Amateur Astronomy: Tools and Techniques for Astronomical Observations. Astronomy Series. Courier Dover Publications. p. 9. ISBN 0-486-42820-6.
- ^ a b Norris, Jackson M.; et al. (December 2011). "Non-detection of the Putative Substellar Companion to HD 149382". The Astrophysical Journal. 743 (1): 88. arXiv:1110.1384. Bibcode:2011ApJ...743...88N. doi:10.1088/0004-637X/743/1/88. S2CID 118337277.
