Astronomy:HD 134687
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas |
| 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 |
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]
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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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, doi:10.1002/asna.200911355, Bibcode: 2010AN....331..349H.
- ↑ 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 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ 6.0 6.1 Buscombe, W.; Kennedy, P. M. (August 1962), "Two B-Type Spectroscopic Binaries", Publications of the Astronomical Society of the Pacific 74 (439): 323, doi:10.1086/127818, Bibcode: 1962PASP...74..323B
- ↑ 7.0 7.1 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, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ 8.0 8.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ 9.0 9.1 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, doi:10.1086/511002, Bibcode: 2007AJ....133.1092W.
- ↑ "HD 134687". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+134687.
- ↑ 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, doi:10.1088/0004-637X/756/2/133, 133, Bibcode: 2012ApJ...756..133C.
- ↑ 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, doi:10.1051/aas:1996213, Bibcode: 1996A&AS..118..481B.
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