Location of Gliese 832 in the constellation Grus | |
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Grus |
Right ascension | 21h 33m 33.97512s [1] |
Declination | −49° 00′ 32.3994″ [1] |
Apparent magnitude (V) | 8.66 [2] |
Characteristics | |
Evolutionary stage | main-sequence star |
Spectral type | M2V [3] |
B−V color index | 1.52 [2] |
Astrometry | |
Radial velocity (Rv) | 12.72±0.13 [1] km/s |
Proper motion (μ) | RA: −45.917 mas/yr [1] Dec.: −816.875 mas/yr [1] |
Parallax (π) | 201.3252±0.0237 mas [1] |
Distance | 16.200 ± 0.002 ly (4.9671 ± 0.0006 pc) |
Absolute magnitude (MV) | 10.19 [2] |
Details | |
Mass | 0.441 ± 0.011 [4] M☉ |
Radius | 0.442 ± 0.018 [4] R☉ |
Luminosity (bolometric) | 0.0276 ± 0.0009 [4] L☉ |
Luminosity (visual, LV) | 0.007 [note 1] L☉ |
Surface gravity (log g) | 4.7 [2] cgs |
Temperature | 3,539+79 −74 [4] K |
Metallicity [Fe/H] | −0.06 ± 0.04 [5] dex |
Rotation | 37.5+1.4 −1.5 d [6] |
Age | 6±1.5 [6] Gyr |
Other designations | |
Database references | |
SIMBAD | The star |
planet c | |
planet b | |
Exoplanet Archive | data |
Gliese 832 (Gl 832 or GJ 832) is a red dwarf of spectral type M2V in the southern constellation Grus. [8] The apparent visual magnitude of 8.66 [2] means that it is too faint to be seen with the naked eye. It is located relatively close to the Sun, at a distance of 16.2 light years [1] and has a high proper motion of 818.16 milliarcseconds per year. [1] Gliese 832 has just under half the mass and radius of the Sun. [8] Its estimated rotation period is a relatively leisurely 46 days. [3] The star is roughly 6 billion years old. [6]
This star achieved perihelion some 52,920 years ago when it came within an estimated 15.71 ly (4.817 pc) of the Sun. [9]
Gliese 832 emits X-rays. [10] Despite the strong flare activity, Gliese 832 is producing on average less ionizing radiation than the Sun. Only at extremely short radiation wavelengths (<50nm) does its radiation intensity rise above the level of quiet Sun, but does not reach levels typical for active Sun. [11]
Gliese 832 hosts one known planet, with a second planet having been refuted in 2022. [6] No additional planets were found as of 2024. [12]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (years) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 0.8+0.12 −0.11 MJ | 3.53+0.15 −0.16 | 9.88+0.34 −0.33 | 0.069+0.026 −0.027 | 54.9+6.6 −4.9 or 125.1+4.9 −6.6 ° | — |
In September 2008, it was announced that a Jupiter-like planet, designated Gliese 832 b, had been detected in a long-period, near-circular orbit around this star, with a false alarm probability of a negligible 0.05%. It would induce an astrometric perturbation on its star of at least 0.95 milliarcseconds and is thus a good candidate for being detected by astrometric observations. Despite its relatively large angular distance, direct imaging is problematic due to the star–planet contrast. [2] The orbital solution of the planet was refined in 2011. [14] In 2023, an astrometric detection of the planet was announced, determining its inclination and revealing a true mass 80% the mass of Jupiter. [13]
Gliese 832 c was the second reported planet in the Gliese 832 system, believed to be of super-Earth mass. [8] It was announced to orbit in the optimistic habitable zone but outside the conservative habitable zone of its parent star. [15] The planet Gliese 832 c was believed to be in, or very close to, the right distance from its sun to allow liquid water to exist on its surface. [8] However, doubts were raised about the existence of planet c by a 2015 study, which found that its orbital period is close to the stellar rotation period. [3] The existence of the planet was refuted in 2022, when a study found that the radial velocity signal shows characteristics of a signal originating from stellar activity, and not from a planet. [6]
The region between Gliese 832 b and where Gliese 832 c would be is a zone where additional planets are possible. [16]
If this system has a comet disc, it is not "brighter than the fractional dust luminosity 10−5" according to a 2012 Herschel study. [17]