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] 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] 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] 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] 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[edit]

Gliese 832 hosts two known planets.

Discovery of Jupiter mass planet[edit]

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[edit]

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] and has since been given the scientific name Gliese 832 c.[8] 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]

Search for cometary disc[edit]

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[edit]

Gliese 832 emits X-rays.[12]

See also[edit]

Notes[edit]

  1. ^ Using the absolute visual magnitude of Gliese 832 with a bolometric correction of [5] the bolometric magnitude can be calculated as , the bolometric magnitude of the Sun ,[6] and so therefore the bolometric luminosity can be calculated by
  2. ^ Using the absolute visual magnitude of Gliese 832 and the absolute visual magnitude of the Sun , the visual luminosity can be calculated by

References[edit]

  1. ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction" (PDF). Astronomy and Astrophysics 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c d e f g h Bailey, J.; Butler, R. P.; Tinney, C. G.; Jones, H. R. A.; O'Toole, S.; Carter, B. D.; Marcy, G. W. (2008). "A Jupiter-like Planet Orbiting the Nearby M Dwarf GJ832". The Astrophysical Journal 690 (1): 743–747. arXiv:0809.0172. Bibcode:2009ApJ...690..743B. doi:10.1088/0004-637X/690/1/743. 
  3. ^ a b c Suárez Mascareño, A.; et al. (September 2015), "Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators", Monthly Notices of the Royal Astronomical Society 452 (3): 2745−2756, arXiv:1506.08039, Bibcode:2015MNRAS.452.2745S, doi:10.1093/mnras/stv1441. 
  4. ^ Johnson, H. M.; Wright, C. D. (1983). "Predicted infrared brightness of stars within 25 parsecs of the sun". The Astrophysical Journal Supplement Series 53: 643–771. Bibcode:1983ApJS...53..643J. doi:10.1086/190905. 
  5. ^ Flower, Phillip J. (September 1996). "Transformations from Theoretical Hertzsprung-Russell Diagrams to Color-Magnitude Diagrams: Effective Temperatures, B-V Colors, and Bolometric Corrections". The Astrophysical Journal 469: 355. Bibcode:1996ApJ...469..355F. doi:10.1086/177785. 
  6. ^ Torres, Guillermo (November 2010). "On the Use of Empirical Bolometric Corrections for Stars". The Astronomical Journal 140 (5): 1158–1162. arXiv:1008.3913. Bibcode:2010AJ....140.1158T. doi:10.1088/0004-6256/140/5/1158. Lay summary. 
  7. ^ Interpolated value from NASA Exoplanet Archive, per: Bessell, M. S. (1995). "The Temperature Scale for Cool Dwarfs". In Tinney, C. G. The Bottom of the Main Sequence - and Beyond, Proceedings of the ESO Workshop. Springer-Verlag. p. 123. Bibcode:1995bmsb.conf..123B. 
  8. ^ a b c d e f g "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. ^ a b Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics 575: 13, arXiv:1412.3648, Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, A35. 
  10. ^ Wittenmyer, R.A.; Tuomi, M.; Butler, R.P.; Jones, H. R. A.; O'Anglada-Escude, G.; Horner, J.; Tinney, C.G.; Marshall, J.P.; Carter, B.D.; et al. (2014). "GJ 832c: A super-earth in the habitable zone" 1406: 5587. arXiv:1406.5587. Bibcode:2014ApJ...791..114W. doi:10.1088/0004-637X/791/2/114. 
  11. ^ B. C. Matthews; forthcoming study promised in Lestrade, J.-F.; Matthews, B. C.; Sibthorpe, B.; Kennedy, G. M.; Wyatt, M. C.; Bryden, G.; Greaves, J. S.; Thilliez, E.; Moro-Martín, A.; Booth, M.; Dent, W. R. F.; Duchêne, G.; Harvey, P. M.; Horner, J.; Kalas, P.; Kavelaars, J. J.; Phillips, N. M.; Rodriguez, D. R.; Su, K. Y. L.; Wilner, D. J. (2012). "A DEBRIS Disk Around The Planet Hosting M-star GJ581 Spatially Resolved with Herschel". Astronomy and Astrophysics 548: A86. arXiv:1211.4898. Bibcode:2012A&A...548A..86L. doi:10.1051/0004-6361/201220325. 
  12. ^ Schmitt, J. H. M. M.; Fleming, T. A.; Giampapa, M. S. (1995). "The X-ray view of the low-mass stars in the solar neighborhood". The Astrophysical Journal 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149. 

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