 Gliese 687 is the small orange star located in the center of the above image. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco |
| Right ascension | 17 36 25.89931 |
| Declination | +68° 20′ 20.9096″ |
| Apparent magnitude (V) | 9.15 |
| Characteristics | |
| Spectral type | M3.5 V |
| U−B color index | 1.06 |
| B−V color index | 1.49 |
| Astrometry | |
| Radial velocity (Rv) | −28.90±0.13 km/s |
| Proper motion (μ) | RA: –320.675 mas/yr Dec.: –1269.893 mas/yr |
| Parallax (π) | 219.7898 ± 0.0210 mas |
| Distance | 14.839 ± 0.001 ly (4.5498 ± 0.0004 pc) |
| Absolute magnitude (MV) | 10.87 |
| Details | |
| Mass | 0.40±0.02 M☉ |
| Radius | 0.4183±0.0070 R☉ |
| Luminosity | 0.02128±0.00023 L☉ |
| Surface gravity (log g) | 4.66 cgs |
| Temperature | 3,413±28 K |
| Metallicity | +0.11 ± 0.20 dex |
| Rotation | 61.8±1.0 d |
| Rotational velocity (v sin i) | <2.8 km/s |
| Other designations | |
| BD+68 946, GJ 687, HIP 86162, SAO 17568, LHS 450, LTT 15232, PLX 4029.00 | |
| Database references | |
| SIMBAD | data |
  Gliese 687Location of Gliese 687 in the constellation Draco | |
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 a distance of 14.84 light-years (4.55 parsecs). Even though it is close by, it has an apparent 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. It is known to have a Neptune-mass planet. Old books and articles refer to it as Argelander Oeltzen 17415.
Properties
Gliese 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. It seems to rotate every 60 days and exhibit some chromospheric activity.
It displays no excess of infrared radiation that would indicate orbiting dust.
Gliese 687 is a solitary red dwarf that emits X-rays.
Planetary system
In 2014, Gliese 687 was discovered to have a planet, Gliese 687 b, with a minimum mass of 18.394 Earth masses (which makes it comparable to Neptune), an orbital period of 38.14 days, a low orbital eccentricity and inside the habitable zone. Another Neptune-mass planet candidate was discovered in 2020, in a further out and much colder orbit.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥17.2±1.0 M🜨 | 0.163±0.003 | 38.142±0.007 | 0.17±0.05 | — | — |
| c | ≥16.0±4.1 M🜨 | 1.165±0.023 | 727.562±12.198 | 0.40±0.22 | — | — |
See also
- List of nearest stars and brown dwarfs
- List of exoplanets discovered in 2014 - Gliese 687 b
- List of exoplanets discovered in 2020 - Gliese 687 c
References
- ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ "LHS 450 -- High proper-motion Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Archived from the original on 2017-11-09. Retrieved 2009-11-12.
- Endl, Michael; Cochran, William D.; Kürster, Martin; Paulson, Diane B.; Wittenmyer, Robert A.; MacQueen, Phillip J.; Tull, Robert G. (September 2006). "Exploring the Frequency of Close-in Jovian Planets around M Dwarfs". The Astrophysical Journal. 649 (1): 436–443. arXiv:astro-ph/0606121. Bibcode:2006ApJ...649..436E. doi:10.1086/506465. S2CID 14461746.
- ^ 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. (2020). "Search for Nearby Earth Analogs. III. Detection of ten new planets, three planet candidates, and confirmation of three planets around eleven nearby M dwarfs". The Astrophysical Journal Supplement Series. 250 (2): 29. arXiv:2008.07998. Bibcode:2020ApJS..250...29F. doi:10.3847/1538-4365/abb139. S2CID 221150644.
- ^ Boyajian, Tabetha S.; et al. (2012). "Stellar Diameters and Temperatures. Ii. Main-Sequence K- and M-Stars". The Astrophysical Journal. 757 (2): 112. arXiv:1208.2431. Bibcode:2012ApJ...757..112B. doi:10.1088/0004-637X/757/2/112. ISSN 0004-637X.
- ^ Berger, D. H.; et al. (2006). "First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars". The Astrophysical Journal. 644 (1): 475–483. arXiv:astro-ph/0602105. Bibcode:2006ApJ...644..475B. doi:10.1086/503318. S2CID 14966363.
- ^ Burt, Jennifer; Vogt, Steven S.; Butler, R. Paul; Hanson, Russell; Meschiari, Stefano; Rivera, Eugenio J.; Henry, Gregory W.; Laughlin, Gregory (2014). "The Lick–Carnegie exoplanet survey: Gliese 687 b: A Neptune-mass planet orbiting a nearby red dwarf". The Astrophysical Journal. 789 (2): 114. arXiv:1405.2929. Bibcode:2014ApJ...789..114B. doi:10.1088/0004-637X/789/2/114. S2CID 17668957.
- Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko, Y.; Gallardo, J.; Barnes, J. R.; Pinfield, D. J. (October 2009). "Rotational Velocities for M Dwarfs". The Astrophysical Journal. 704 (2): 975–988. arXiv:0908.4092. Bibcode:2009ApJ...704..975J. doi:10.1088/0004-637X/704/2/975. S2CID 119203469.
- Lynn, W. T. (June 1890). "On the proper motions of three stars". Monthly Notices of the Royal Astronomical Society. 50 (8): 519–520. Bibcode:1890MNRAS..50..519L. doi:10.1093/mnras/50.8.519.
- Gautier, Thomas N., III; et al. (September 2007). "Far-Infrared Properties of M Dwarfs". The Astrophysical Journal. 667 (1): 527–536. arXiv:0707.0464. Bibcode:2007ApJ...667..527G. doi:10.1086/520667. S2CID 15732144.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-ray view of the low-mass stars in the solar neighborhood". Astrophys. J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.
External links
- NEXXUS page Archived 2012-02-22 at the Wayback Machine
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