| 词条 | Gliese 687 |
| 释义 |
| name=Gliese 687 }}{{Starbox observe | epoch=J2000 | ra={{RA|17|36|25.8999}} | dec={{DEC|+68|20|20.909}} | appmag_v=9.15[3] | constell=Draco }}{{Starbox character | class=M3.5 V[4] | b-v=1.49 | u-b=1.06 | variable= }}{{Starbox astrometry | radial_v=–23.2[5] | prop_mo_ra=–320.47 | prop_mo_dec=–1269.55 | parallax=220.86 | p_error=0.92 | parallax_footnote= | absmag_v=10.87 }}{{Starbox detail | mass={{nowrap|0.401 ± 0.040}}[9] | radius={{nowrap|0.492 ± 0.038}}[9] | luminosity= | temperature={{nowrap|3,095 ± 107}}[9] | metal_fe=+0.11 ± 0.20[9] | rotational_velocity=<2.8[13] | gravity=4.66[9] | age= }}{{Starbox catalog | names=BD +68°946, GCTP 4029.00, GJ 687, HIP 86162, LHS 450, LTT 15232, SAO 17568.[3] }}{{Starbox reference | Simbad = GJ+687 }}{{Starbox end}}Gliese 687, or GJ 687 (Gliese–Jahreiß 687) is a red dwarf in the constellation Draco. This is one of the closest stars to the Sun and lies at an approximate distance of less than 15 light years. Even though it is close by, it has a magnitude of about 9, so it can only be seen through a moderately sized telescope. Gliese 687 has a high proper motion, advancing 1.304 arcseconds per year across the sky. It has a net relative velocity of about 39 km/s.[3] It is known to have a Neptune-mass planet.[1] PropertiesGliese 687 has about 40% of the Sun's mass and nearly 50% of the Sun's radius. Compared to the Sun, it has a slightly higher proportion of elements with higher atomic numbers than helium.[9] It appears to have a rotation of 60 days and to be somewhat chromospherically active. It displays no excess of infrared radiation that would indicate orbiting dust.[2] Planetary SystemIt is known to have a planet, Gliese 687 b, with a mass of 18.394 Earth masses (which makes it comparable to Neptune), an orbital period of 38.14 days, and a low orbital eccentricity.[1] {{OrbitboxPlanet begin}}{{OrbitboxPlanet| exoplanet = b | mass_earth = 18.394 | period = 38.14 | semimajor = 0.16353 | eccentricity = 0.04 }}{{Orbitbox end}} X-ray sourceGliese 687 is a solitary red dwarf that emits X-rays.[3] See also
References1. ^1 [https://arxiv.org/abs/1405.2929 The Lick–Carnegie exoplanet survey: Gliese 687 b: A Neptune-mass planet orbiting a nearby red dwarf] [4][5][6][7][8]2. ^{{cite journal | author=Gautier, Thomas N., III |display-authors=etal | title=Far-Infrared Properties of M Dwarfs | journal=The Astrophysical Journal | volume=667 | issue=1 | pages=527–536 |date=September 2007 | doi=10.1086/520667 | bibcode=2007ApJ...667..527G |arxiv = 0707.0464 }} 3. ^{{ cite journal |doi=10.1086/176149 |author1=Schmitt JHMM |author2=Fleming TA |author3=Giampapa MS |title=The X-ray view of the low-mass stars in the solar neighborhood |journal=Astrophys. J. |date=September 1995 |volume=450 |issue=9 |pages=392–400 |bibcode=1995ApJ...450..392S }} 4. ^1 {{cite journal |author1=Endl, Michael |author2=Cochran, William D. |author3=Kürster, Martin |author4=Paulson, Diane B. |author5=Wittenmyer, Robert A. |author6=MacQueen, Phillip J. |author7=Tull, Robert G. | title=Exploring the Frequency of Close-in Jovian Planets around M Dwarfs | journal=The Astrophysical Journal | volume=649 | issue=1 | pages=436–443 |date=September 2006 | doi=10.1086/506465 | bibcode=2006ApJ...649..436E | arxiv=astro-ph/0606121 }} 5. ^1 {{cite conference | last=Evans | first=D. S. | date=June 20–24, 1966 | title=The Revision of the General Catalogue of Radial Velocities | booktitle=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 | location=University of Toronto | publisher=Academic Press | editors=Alan Henry Batten and John Frederick Heard | bibcode=1967IAUS...30...57E }} 6. ^1 2 3 4 5 6 {{cite journal | author=Berger, D. H. |display-authors=etal | title=First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars | journal=The Astrophysical Journal | year=2006 | volume=644 | issue=1 | pages=475–483 | doi=10.1086/503318 | bibcode=2006ApJ...644..475B|arxiv = astro-ph/0602105 }} 7. ^1 {{cite journal |author1=Jenkins, J. S. |author2=Ramsey, L. W. |author3=Jones, H. R. A. |author4=Pavlenko, Y. |author5=Gallardo, J. |author6=Barnes, J. R. |author7=Pinfield, D. J. | title=Rotational Velocities for M Dwarfs | journal=The Astrophysical Journal | volume=704 | issue=2 | pages=975–988 |date=October 2009 | doi=10.1088/0004-637X/704/2/975 | bibcode=2009ApJ...704..975J |arxiv = 0908.4092 }} 8. ^1 2 3 {{cite web | title=LHS 450 -- High proper-motion Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=LHS+450 | accessdate=2009-11-12 }} }} Notes{{reflist|group=note}}External links
6 : Draco (constellation)|Local Bubble|M-type main-sequence stars|Hipparcos objects|Gliese and GJ objects|Durchmusterung objects |
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