Summary
HD 134687 (e Lupi) is a binary star system in the southern constellation Lupus. It is visible to the naked eye with an apparent visual magnitude of 4.81.[2] The distance to HD 134687 can be estimated from its annual parallax shift of 7.6 mas,[1] yielding roughly 430 light years. It is a member of the ~11 million year old Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association, the closest OB association to the Sun.[11]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15h 12m 49.58802s[1] |
| Declination | −44° 30′ 01.4867″[1] |
| Apparent magnitude (V) | 4.81[2] |
| Characteristics | |
| Spectral type | B3 IV/V[3] |
| B−V color index | −0.177±0.011[4] |
| Astrometry | |
| Radial velocity (Rv) | +13.5±7.4[5] km/s |
| Proper motion (μ) | RA: −22.015[1] mas/yr Dec.: −22.164[1] mas/yr |
| Parallax (π) | 7.6373 ± 0.9664 mas[1] |
| Distance | approx. 430 ly (approx. 130 pc) |
| Absolute magnitude (MV) | −1.11[4] |
| Orbit[6] | |
| Period (P) | 0.901407 d |
| Eccentricity (e) | ≤ 0.03 |
| Periastron epoch (T) | 0.366 |
| Details | |
| e Lup A | |
| Mass | 6.0±0.1[7] M☉ |
| Radius | 7.1[8] R☉ |
| Luminosity (bolometric) | 997[2] L☉ |
| Temperature | 17,100[2] K |
| Rotational velocity (v sin i) | 13[9] km/s |
| Age | 20.3±4.8 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary star system. The pair have a nearly circular orbit with an eccentricity of at or below 0.03 and a period of 0.901407 days (21.6338 h). The primary has an a sin i value of 2.735×105 km, which only gives a lower bound for the semimajor axis a since the orbital inclination i to the line of sight is unknown.[6] The system is a source for X-ray emission.[12]
The visible component has a stellar classification of B3 IV/V,[3] matching a B-type star showing a spectrum with mixed traits of a main sequence and a subgiant star. It is 20 million years old with a projected rotational velocity of 13 km/s.[9] The star has 6.0[7] times the mass of the Sun and 7.1[8] times the Sun's radius. It is radiating 997[2] times the Sun's luminosity from its photosphere at an effective temperature of 17,100 K.[2]
References edit
- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
- ^ a b c d e f Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
- ^ a b 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.
- ^ a b 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.
- ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b Buscombe, W.; Kennedy, P. M. (August 1962), "Two B-Type Spectroscopic Binaries", Publications of the Astronomical Society of the Pacific, 74 (439): 323, Bibcode:1962PASP...74..323B, doi:10.1086/127818
- ^ a b Tetzlaff, N.; et al. (January 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, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
- ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (2) (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ a b Wolff, S. C.; Strom, S. E.; Dror, D.; Venn, K. (2007), "Rotational Velocities for B0-B3 Stars in Seven Young Clusters: Further Study of the Relationship between Rotation Speed and Density in Star-Forming Regions", The Astronomical Journal, 133 (3): 1092–1103, arXiv:astro-ph/0702133, Bibcode:2007AJ....133.1092W, doi:10.1086/511002, S2CID 119074863.
- ^ "HD 134687". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-22.
- ^ Chen, Christine H.; et al. (September 2012), "A Spitzer MIPS Study of 2.5-2.0 M⊙ Stars in Scorpius–Centaurus", The Astrophysical Journal, 756 (2): 24, arXiv:1207.3415, Bibcode:2012ApJ...756..133C, doi:10.1088/0004-637X/756/2/133, S2CID 119278056, 133.
- ^ Berghoefer, T. W.; Schmitt, J. H. M. M.; Cassinelli, J. P. (September 1996), "The ROSAT all-sky survey catalogue of optically bright OB-type stars", Astronomy and Astrophysics Supplement, 118 (3): 481–494, Bibcode:1996A&AS..118..481B, doi:10.1051/aas:1996213.