Gliese 832

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Template:Short description

Gliese 832
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Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Grus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 8.66[2]
Characteristics
Evolutionary stage main-sequence star
Spectral type M2V[3]
B−V Template:Engvar 1.52[2]
Astrometry
Radial velocity (Rv)Script error: No such module "val".[1] km/s
Proper motion (μ) RA: Script error: No such module "val". mas/yr[1]
Dec.: Script error: No such module "val". mas/yr[1]
Parallax (π)201.3252±0.0237 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)10.19[2]
Details
Mass0.441 ± 0.011[4] Template:Solar mass
Radius0.442 ± 0.018[4] Template:Solar radius
Luminosity (bolometric)0.0276 ± 0.0009[4] Template:Solar luminosity
Luminosity (visual, LV)0.007[note 1] Template:Solar luminosity
Surface gravity (log g)4.7[2] cgs
TemperatureScript error: No such module "val".[4] K
Metallicity [Fe/H]−0.06 ± 0.04[5] dex
RotationScript error: No such module "val".[6]
AgeScript error: No such module "val".[6] Gyr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[7]
Database references
SIMBADThe star
planet c
planet b
Exoplanet Archivedata

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Gliese 832 (Gl 832 or GJ 832) is a red dwarf star of spectral type M2V in the southern constellation Grus.Template:R 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.Template:R 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 Script error: No such module "convert". of the Sun.[8]

Gliese 832 emits X-rays.[9] 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 the quiet Sun, but does not reach levels typical for the active Sun.[10]

Planetary system

Gliese 832 hosts one known planet, with a second planet having been refuted in 2022.[6] No additional planets were found as of 2024.[11]

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Gliese 832 b

Script error: No such module "Labelled list hatnote". 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 planet was detected astrometrically by two different 2023 studies, determining its inclination and revealing a true mass close to the mass of Jupiter.[12][13]

Gliese 832 c

Gliese 832 c was the second reported planet in the Gliese 832 system, believed to be of super-Earth mass (minimum mass about 5 times the mass of Earth).Template:R It was announced to orbit in the optimistic habitable zone but outside the conservative habitable zone of its parent star.[14] 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.Template:R 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]

Limits on additional planets

A 2016 study found that additional planets are possible in the region between the two planets thought to exist at the time, in particular planets less than 15 Earth masses orbiting between 0.25-2.0 AU.[15] As of 2024, no additional planets had been found and Gliese 832 b remains the only known planet in the system. The radial velocity data sets an upper limit of 1.5 Earth masses on any undetected planet with a period up to 100 days.[11]

Search for cometary disc

If this system has a comet disc, it is not "brighter than the fractional dust luminosity 10−5" according to a 2012 Herschel study.[16]

See also

Notes

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  1. ↑ Using the absolute visual magnitude of Gliese 832 MV∗=10.19 and the absolute visual magnitude of the Sun MV⊙=4.83, the visual luminosity can be calculated by LV∗LV⊙=100.4(MV⊙−MV∗)

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References

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  1. ↑ a b c d e f g Template:Cite Gaia DR3
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  3. ↑ a b c Script error: No such module "citation/CS1".
  4. ↑ a b c d Script error: No such module "Citation/CS1".
  5. ↑ Script error: No such module "Citation/CS1".
  6. ↑ a b c d e Script error: No such module "Citation/CS1".
  7. ↑ Template:Cite simbad
  8. ↑ Script error: No such module "citation/CS1".
  9. ↑ Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "Citation/CS1".
  11. ↑ a b Script error: No such module "Citation/CS1".
  12. ↑ Script error: No such module "Citation/CS1".
  13. ↑ Script error: No such module "Citation/CS1".
  14. ↑ Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ B. C. Matthews; forthcoming study promised in Script error: No such module "Citation/CS1".
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Template:Sky Template:Nearest systems Template:Stars of Grus

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