格利泽687

格利泽687，或称GJ 687（Gliese–Jahreiß 687）是天龙座中的一颗红矮星。它是离太阳最近的恒星之一，距离大约小于15光年。尽管它离太阳很近，但它的视星等只有9等，因此需要用适当的望远镜才能观测到。这颗恒星的自行很大，每年增加1.304 角秒。它的径向速度为大约39 km/s。目前已知該恆星旁有一顆質量與海王星相當的行星存在。 格利泽687的质量为太阳质量的40%，半径为太阳半径的50%。与太阳相比，它含有的重元素比例（原子序数比氦大）略高一些。这颗星没有表现出紅外過量，因此应当不存在环绕的尘埃盘。因此，目前还未发现有围绕它运转的伴星。 格利泽687是极少见的能发射X射线的紅矮星。 2014年，發現有一顆行星環繞格利泽687，名為格利泽687 b，最小質量為18.394個地球質量（與海王星相當），軌道周期為38.14天，軌道偏心率低，位於宜居帶內。2020年，在更遠更冷的軌道上發現了另一顆海王星質量的候選行星。 临近恒星列表 Perryman, M. A. C.; et al. The HIPPARCOS Catalogue. Astronomy & Astrophysics. July 1997, 323: L49–L52. Bibcode:1997A&A...323L..49P.  LHS 450 -- High proper-motion Star. SIMBAD. Centre de Données astronomiques de Strasbourg. [2009-11-12]. （原始内容存档于2017-11-09）.  Endl, Michael; Cochran, William D.; Kürster, Martin; Paulson, Diane B.; Wittenmyer, Robert A.; MacQueen, Phillip J.; Tull, Robert G. Exploring the Frequency of Close-in Jovian Planets around M Dwarfs. The Astrophysical Journal. September 2006, 649 (1): 436–443. Bibcode:2006ApJ...649..436E. arXiv:astro-ph/0606121 . doi:10.1086/506465.  Evans, D. S. The Revision of the General Catalogue of Radial Velocities. Alan Henry Batten and John Frederick Heard (编). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: Academic Press. June 20–24, 1966. Bibcode:1967IAUS...30...57E.  Berger, D. H.; et al. First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars. The Astrophysical Journal. 2006, 644 (1): 475–483. Bibcode:2006ApJ...644..475B. arXiv:astro-ph/0602105 . doi:10.1086/503318.  Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Gallardo, J.; Barnes, J. R.; Pinfield, D. J. Rotational Velocities for M Dwarfs. The Astrophysical Journal. October 2009, 704 (2): 975–988. Bibcode:2009ApJ...704..975J. doi:10.1088/0004-637X/704/2/975.  The Lick–Carnegie exoplanet survey: Gliese 687 b: A Neptune-mass planet orbiting a nearby red dwarf 互联网档案馆的存檔，存档日期2014-03-27. Gautier, Thomas N., III; et al. Far-Infrared Properties of M Dwarfs. The Astrophysical Journal. September 2007, 667 (1): 527–536. Bibcode:2007ApJ...667..527G. doi:10.1086/520667.  Hinz, Joannah L.; McCarthy, Donald W., Jr.; Simons, Doug A.; Henry, Todd J.; Kirkpatrick, J. Davy; McGuire, Patrick C. A Near-Infrared, Wide-Field, Proper-Motion Search for Brown Dwarfs. The Astronomical Journal. April 2002, 123 (4): 2027–2032. Bibcode:2002AJ....123.2027H. arXiv:astro-ph/0201140 . doi:10.1086/339555.  Endl, Michael; Cochran, William D.; Tull, Robert G.; MacQueen, Phillip J. A Dedicated M Dwarf Planet Search Using The Hobby-Eberly Telescope. The Astronomical Journal. December 2003, 126 (6): 3099–3107. Bibcode:2003AJ....126.3099E. arXiv:astro-ph/0308477 . doi:10.1086/379137.  Schmitt JHMM, Fleming TA, Giampapa MS. The X-ray view of the low-mass stars in the solar neighborhood. Ap J. September 1995, 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.  Feng, Fabo; Shectman, Stephen A.; Clement, Matthew S.; Vogt, Steven S.; Tuomi, Mikko; Teske, Johanna K.; Burt, Jennifer; Crane, Jeffrey D.; Holden, Bradford; Sharon Xuesong Wang; Thompson, Ian B.; Diaz, Matias R.; Paul Butler, R. Search for Nearby Earth Analogs. III. Detection of ten new planets, three planet candidates, and confirmation of three planets around eleven nearby M dwarfs. 2020. S2CID 221150644. arXiv:2008.07998 . doi:10.3847/1538-4365/abb139 .  NEXXUS page （页面存档备份，存于互联网档案馆）