Gliese 832

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Gliese 832
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Grus
Right ascension 21h 33m 33.975s[1]
Declination −49° 00′ 32.42″[1]
Apparent magnitude (V) 8.66[2]
Characteristics
Spectral type M2V[3]
B−V color index 1.52[2]
Astrometry
Radial velocity (Rv) 18.0 km/s
Proper motion (μ) RA: −46.05 ± 0.95[1] mas/yr
Dec.: −817.63 ± 0.59[1] mas/yr
Parallax (π) 201.87 ± 1.01[1] mas
Distance 16.16 ± 0.08 ly
(4.95 ± 0.02 pc)
Absolute magnitude (MV) 10.19[2]
Details
Mass 0.45 ± 0.05[2] M☉
Radius 0.48[4] R☉
Luminosity (bolometric) 0.035[note 1] L☉
Luminosity (visual, LV) 0.007[note 2] L☉
Surface gravity (log g) 4.7[2] cgs
Temperature 3,620[7] K
Metallicity −0.31 ± 0.2[2]
Rotation 45.7±9.3 d[3]
Other designations
CD-49°13515, HD 204961, HIP 106440, LHS 3865, PLX 5190
Database references
SIMBAD The star
planet c
planet b
Exoplanet Archive data
Extrasolar Planets
Encyclopaedia		 data
Data sources:
Hipparcos Catalogue,
HD

Gliese 832 (Gl 832 or GJ 832) is a red dwarf of spectral type M2V in the southern constellation Grus.[8]:{{{3}}} 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 16.1 light years[8]:{{{3}}} and has a high proper motion of 818.93 mas per year.[9] Gliese 832 has just under half the mass and radius of the Sun.[8]:{{{3}}} Its estimated rotation period is a relatively leisurely 46 days.[3]

In 2014, Gliese 832 was announced to be hosting the closest potentially habitable Earth-mass-range exoplanet to the Solar System.[8]:{{{3}}} 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]

Planetary system

Gliese 832 hosts two known planets.

Discovery of Jupiter mass planet

In September 2008, it was announced that a Jupiter-like planet, now designated as Gliese 832 b, had been detected in a long-period, near-circular orbit around this star (false alarm probability thus far: 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]

Discovery of Gliese 832 c (super-Earth mass planet) in habitable zone

In 2014, a second planet was discovered by astronomers at the University of New South Wales. This one is believed to be of super-Earth mass[8]:{{{3}}} and has since been given the scientific name Gliese 832 c.[8]:{{{3}}} It was announced to orbit in the optimistic habitable zone but outside the conservative habitable zone of its parent star.[10]

The planet is believed to be in, or very close to, the right distance from its sun to allow liquid water to exist on its surface.[8]:{{{3}}}

Search for cometary disc

If this system has a comet disc, it is undetectable "brighter than the fractional dust luminosity 10−5" of a recent Herschel study.[11]

The Gliese 832 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
c ≥5.4±1 M⊕ 0.162±0-017 35.68±0.03 0.18 ± 0.13 — —
b ≥0.64 ± 0.06 MJ 3.4 ± 0.4 3416 ± 131 0.12 ± 0.11 — —

X-ray source

Gliese 832 emits X-rays.[12]

See also

Notes

  1. ↑ Using the absolute visual magnitude of Gliese 832 \scriptstyle M_{V_{\ast}}=10.19 with a bolometric correction of \scriptstyle BC=-1.821[5] the bolometric magnitude can be calculated as \scriptstyle M_{bol_{\ast}}=8.369, the bolometric magnitude of the Sun \scriptstyle M_{bol_{\odot}}=4.73,[6] and so therefore the bolometric luminosity can be calculated by \scriptstyle \frac{L_{bol_{\ast}}}{L_{bol_{\odot}}}=10^{0.4\left(M_{bol_{\odot}} - M_{bol_{\ast}}\right)}
  2. ↑ Using the absolute visual magnitude of Gliese 832 \scriptstyle M_{V_{\ast}}=10.19 and the absolute visual magnitude of the Sun \scriptstyle M_{V_{\odot}}=4.83, the visual luminosity can be calculated by \scriptstyle \frac{L_{V_{\ast}}}{L_{V_{\odot}}}=10^{0.4\left(M_{V_{\odot}} - M_{V_{\ast}}\right)}

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found. Vizier catalog entry
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ 3.0 3.1 3.2 Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ Interpolated value from NASA Exoplanet Archive, per: Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 "Nearby Alien Planet May Be Capable of Supporting Life", Mike Wall, Space.com, June 25, 2014, http://www.space.com/26357-exoplanet-habitable-zone-gliese-832c.html
  9. ↑ 9.0 9.1 Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ B. C. Matthews; forthcoming study promised in Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.

Coordinates: Sky map 21h 33m 33.9752s, −49° 00′ 32.422″

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