Gliese 849, or GJ 849, is a small, solitary star in the equatorial constellation of Aquarius. It has a reddish hue and is invisible to the naked eye with an apparent visual magnitude of 10.41.[2] The distance to this star is 28.8 light-years (8.8 parsecs) based on parallax,[1] but it is drifting closer to the Sun with a radial velocity of −15.3 km/s.[2] It has a pair of confirmed gas giant companions.[8]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 09m 40.34431s[1] |
| Declination | –04° 38′ 26.6508″[1] |
| Apparent magnitude (V) | 10.41[2] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | M3.5V[4] |
| U−B color index | 1.055[2] |
| B−V color index | 1.531±0.035[2] |
| V−R color index | 1.12[2] |
| R−I color index | 1.41[2] |
| Astrometry | |
| Radial velocity (Rv) | −15.26±0.10[2] km/s |
| Proper motion (μ) | RA: 1,132.583(39) mas/yr[1] Dec.: −22.157(37) mas/yr[1] |
| Parallax (π) | 113.4447 ± 0.0300 mas[1] |
| Distance | 28.750 ± 0.008 ly (8.815 ± 0.002 pc) |
| Absolute magnitude (MV) | 10.62[2] |
| Details[5] | |
| Mass | 0.465±0.011 M☉ |
| Radius | 0.464±0.018 R☉ |
| Luminosity | 0.02887±0.00025 L☉ |
| Surface gravity (log g) | 4.771±0.032 cgs |
| Temperature | 3,467±68[6] K |
| Metallicity [Fe/H] | 0.09±0.09[6] dex |
| Rotation | 40.45+0.19 −0.18 d[6] |
| Rotational velocity (v sin i) | 2.4[3] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
| Planet | |
| Gliese 849b | data Archived 2019-06-05 at the Wayback Machine |
The stellar classification of GJ 849 is M3.5V,[4] which means this is a small red dwarf star generating energy through hydrogen fusion at its core region. Various studies have found super-solar abundances in the spectra,[8] indicating that the elemental abundances of higher mass elements is significantly higher than in the Sun. The star has about half the mass and size of the Sun,[3] and is spinning slowly with a rotation period of approximately 39 days.[9] The estimated age of the star is more than three billion years.[3] It is radiating a mere 2.9%[5] of the luminosity of the Sun from its photosphere at an effective temperature of 3,490 K.[5]
Planetary system
In late 2006, a long-period Jupiter-like exoplanet was reported to be orbiting the red dwarf in a period just over 5 years in length. There was also a linear trend in the radial velocities which suggested another longer period companion.[3] The trend in the radial velocities was confirmed in 2013.[10] An orbit for the second exoplanet was finally determined in 2015. The first planet discovered, Gliese 849 b, was the first planet discovered orbiting a red dwarf with a semi-major axis greater than 0.21 AU.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥0.893+0.094 −0.097 MJ |
2.32+0.11 −0.13 |
1925.31±6.5 | 0.029±0.019 | — | — |
| c | ≥0.99±0.11 MJ | 4.95+0.25 −0.28 |
5990+110 −100 |
0.092+0.038 −0.036 |
— | — |
See also
References
External links
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