Gliese 649

Gliese 649 is a red dwarf star in the constellation of Hercules, located roughly 34 light years from the Sun. The star has been found to host an extrasolar planet.

Gliese 649

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Hercules
Right ascension	16^h 58^m 08.8498^s[1]
Declination	25° 44′ 38.9711″[1]
Apparent magnitude (V)	9.62
Characteristics
Spectral type	M1.5V
Apparent magnitude (B)	11.21
Apparent magnitude (R)	8.8
Apparent magnitude (I)	8.0
Apparent magnitude (J)	6.448
Apparent magnitude (H)	5.865
Apparent magnitude (K)	5.624
B−V color index	1.496
V−R color index	0.8
R−I color index	0.8
Astrometry
Radial velocity (Rv)	6.4 km/s
Proper motion (μ)	RA: −115.479±0.041[1] mas/yr Dec.: −507.887±0.047[1] mas/yr
Parallax (π)	96.3141 ± 0.0311[1] mas
Distance	33.86 ± 0.01 ly (10.383 ± 0.003 pc)
Absolute magnitude (MV)	9.595
Details
Mass	0.54[2] M☉
Radius	0.5387±0.0157[2] R☉
Luminosity	0.0432±0.0013[2] L☉
Temperature	3590±45[2] K
Metallicity [Fe/H]	−0.04±0.17[3] dex
Age	0.48 Gyr
Other designations
HIP 83043, TYC 2063-00479-1, BD+25 3173, 2MASS J16580884+2544392
Database references
SIMBAD	data
Exoplanet Archive	data
ARICNS	data
Extrasolar Planets Encyclopaedia	data

A planetary companion

According to Johnson et al. (2010) a Saturn-mass planet has been detected around the red dwarf star.[4] It yields 32.8% of Jupiter's mass and is located 1.15 astronomical units from its star in eccentric orbit (e=0.3). Assuming a luminosity of 4.5% that of the Sun, the habitable zone is located at 0.21 AUs, thus the planet should be as cold as if it were located at 5.5 AUs from a Solar-like star. Also accounting different periastron and apastron positions of 0.8 and 1.49 AUs respectively, the planet could likely show seasonal temperature changes.

Debris disk

Using results from the Herschel Space Observatory survey of 21 late-type stars carried out in 2010, a debris disk was discovered between approximately 6 and 30 au. The disk was not detected at 22µm by NASA's Wide-field Infrared Survey Explorer so therefore it is likely to be below 100 Kelvin and similar to the Kuiper belt. The disk was marginally resolved, appearing very asymmetric, and so is probably consistent with being closer to edge-on, rather than face-on, in its inclination.[5]

The Gliese 649 planetary system[4][5]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥ 0.328±0.032 MJ	1.135±0.035	598.3±4.2	0.30±0.08	—	—
Kuiper belt	~6–~30 AU				~45-90°	—

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. von Braun, Kaspar; et al. (2014). "Stellar diameters and temperatures - V. 11 newly characterized exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 438 (3): 2413–2425. arXiv:1312.1792. Bibcode:2014MNRAS.438.2413V. doi:10.1093/mnras/stt2360.
3. Rojas-Ayala, Bárbara; et al. (April 2012). "Metallicity and Temperature Indicators in M Dwarf K-band Spectra: Testing New and Updated Calibrations with Observations of 133 Solar Neighborhood M Dwarfs" (PDF). The Astrophysical Journal. 748 (2): 93. arXiv:1112.4567. Bibcode:2012ApJ...748...93R. doi:10.1088/0004-637X/748/2/93.
4. Johnson, John Asher; et al. (2010). "The California Planet Survey II. A Saturn-Mass Planet Orbiting the M Dwarf Gl649". The Publications of the Astronomical Society of the Pacific. 122 (888): 149–155. arXiv:0912.2730. Bibcode:2010PASP..122..149J. doi:10.1086/651007.
5. Kennedy, Grant M.; et al. (2018). "Kuiper Belt Analogues in Nearby M-type Planet-host Systems". Monthly Notices of the Royal Astronomical Society. 476 (4): 4584–4591. arXiv:1803.02832. Bibcode:2018MNRAS.476.4584K. doi:10.1093/mnras/sty492.

See also

• Gliese 317
• Gliese 849
• List of extrasolar planets