房宿增一

房宿增一（拉丁文名稱為Lambda Librae）是黃道星座天秤座的聯星，拜耳名稱是天秤座λ。它是顆黯淡的恆星，視星等 +5.03，在漆黑的夜晚肉眼隱約可見^[2]。年周視差10.54mas^[1]，因此與太陽的距離是310光年。在這樣的距離上，星際塵埃造成的消光使它的視星等降低0.22等^[6]。

房宿增一（天秤座λ）

觀測資料 曆元 J2000.0
星座	天秤座
星官
赤經	15h 53m 20.05463s[1]
赤緯	−20° 10′ 01.4177″[1]
視星等（V）	5.03[2]
特性
光谱分类	B3 V[3]
U−B 色指数	−0.584[2]
B−V 色指数	−0.023[2]
变星类型	旋轉橢球[4]
天体测定
徑向速度 (Rv)	2999800000000000000♠−2.0±0.5[5] km/s
自行 (μ)	赤经：−9.81[1] mas/yr 赤纬：−26.85[1] mas/yr
视差 (π)	10.54 ± 0.91[1] mas
距离	310 ± 30 ly (95 ± 8 pc)
绝对星等 (MV)	0.56[6]
軌道[7]
繞行週期 (P)	7006125132256000000♠14.4829±0.0004 d
偏心率 (e)	6999270000000000000♠0.27±0.09
近心点 曆元 (T)	2435172.380 ± 0.664 JD
近心點幅角 (ω) (secondary)	7002217000000000000♠217±17°
半振幅 (K1) (primary)	7001285000000000000♠28.5±3.3 km/s
詳細資料
質量	7000501000000000000♠5.01±0.26[8] M☉
半徑	3.9[9] R☉
表面重力 (log g)	4.75
亮度	743[8] L☉
溫度	18,700[8] K
金属量 [Fe/H]	−0.27 dex
自轉速度 (v sin i)	155[10] km/s
年齡	282[6] Myr
其他命名
λ Lib、45 Lib、BD−19°4249、FK5 1415、HD 142096、 HIP 77811、HR 5902、SAO 183895。[11]
參考資料庫
SIMBAD	资料

它是只有單一光譜線的光譜聯星，軌道週期14.48天，離心率0.27^[7]。可以見到的成員是B型主序星，光譜類型B3V^[3]。它是光譜特殊的弱氦星^[12]，並且是顆旋轉橢球變星^[4]。估計它的半徑是太陽的3.9倍^[9]，質量是太陽的5倍^[8]。它是類織女的候選者，意味著它有環繞著恆星的岩屑盤引起的紅外過量特徵^[13]。這個系統也是個X射線源^[14]。

參考資料

1. van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357.
2. Gutierrez-Moreno, Adelina; Moreno, Hugo, A photometric investigation of the Scorpio-Centaurus association, Astrophysical Journal Supplement, June 1968, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.
3. Houk, Nancy; Smith-Moore, M., Michigan catalogue of two-dimensional spectral types for the HD stars 4, Ann Arbor: Dept. of Astronomy, University of Michigan, 1978, Bibcode:1988mcts.book.....H.
4. Hoffleit, Dorrit, A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars, The Journal of the American Association of Variable Star Observers, 1996, 24 (2): 105–116, Bibcode:1996JAVSO..24..105H.
5. de Bruijne, J. H. J.; Eilers, A.-C., Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project, Astronomy & Astrophysics, October 2012, 546: 14, Bibcode:2012A&A...546A..61D, arXiv:1208.3048 , doi:10.1051/0004-6361/201219219, A61.
6. Gontcharov, G. A., Spatial distribution and kinematics of OB stars, Astronomy Letters, November 2012, 38 (11): 694–706, Bibcode:2012AstL...38..694G, arXiv:1606.09028 , doi:10.1134/S1063773712110035.
7. Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; et al, S_B⁹: The ninth catalogue of spectroscopic binary orbits, Astronomy & Astrophysics, 2004, 424 (2): 727, Bibcode:2004A&A...424..727P, arXiv:astro-ph/0406573 , doi:10.1051/0004-6361:20041213.
8. Hohle, M. M.; Neuhäuser, R.; Schutz, B. F., Masses and luminosities of O- and B-type stars and red supergiants, Astronomische Nachrichten, April 2010, 331 (4): 349, Bibcode:2010AN....331..349H, arXiv:1003.2335 , doi:10.1002/asna.200911355.
9. Pasinetti Fracassini, L. E.; et al, Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics, Astronomy and Astrophysics, February 2001, 367: 521–524, Bibcode:2001A&A...367..521P, arXiv:astro-ph/0012289 , doi:10.1051/0004-6361:20000451.
10. Abt, Helmut A.; et al, Rotational Velocities of B Stars, The Astrophysical Journal, 2002, 573: 359, Bibcode:2002ApJ...573..359A, doi:10.1086/340590 .
11. lam Lib -- Spectroscopic binary, SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), [2017-01-30], （原始内容存档于2020-11-05）.
12. Renson, P.; Manfroid, J., Catalogue of Ap, HgMn and Am stars (PDF), Astronomy and Astrophysics, May 2009, 498 (3): 961–966 [2020-05-24], Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788, （原始内容存档 (PDF)于2020-09-15）.
13. Saffe, C.; Gómez, M.; Pintado, O.; González, E., Spectroscopic metallicities of Vega-like stars, Astronomy and Astrophysics, October 2008, 490 (1): 297–305, Bibcode:2008A&A...490..297S, arXiv:0805.3936 , doi:10.1051/0004-6361:200810260.
14. Berghoefer, T. W.; Schmitt, J. H. M. M.; Cassinelli, J. P., The ROSAT all-sky survey catalogue of optically bright OB-type stars, Astronomy and Astrophysics Supplement, September 1996, 118: 481–494, Bibcode:1996A&AS..118..481B.