Gliese 832

Gliese 832 (Gl 832 or GJ 832) is a red dwarf of spectral type M2V in the southern constellation Grus.[11] 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 818.93 milliarcseconds[12] per year.[1] Gliese 832 has just under half the mass and radius of the Sun.[11] Its estimated rotation period is a relatively leisurely 46 days.[3] The star is roughly 9.5 billion years old.[9]

Gliese 832
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Grus
Right ascension 21h 33m 33.9750s[1]
Declination −49° 00′ 32.4035″[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)18.0 km/s
Proper motion (μ) RA: −45.834±0.071[1] mas/yr
Dec.: −816.604±0.064[1] mas/yr
Parallax (π)201.4073 ± 0.0429[1] mas
Distance16.194 ± 0.003 ly
(4.965 ± 0.001 pc)
Absolute magnitude (MV)10.19[2]
Details
Mass0.45 ± 0.05[2] M☉
Radius0.48[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
Temperature3,620[7] K
Metallicity [Fe/H]−0.06±0.04[8] dex
Rotation45.7±9.3 d[3]
Age9.24[9] Gyr
Other designations
CD-49°13515, HD 204961, HIP 106440, LHS 3685, PLX 5190[10]
Database references
SIMBADThe star
planet c
planet b
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia		data
Data sources:
Hipparcos Catalogue,
HD

This star achieved perihelion some 52,920 years ago when it came within an estimated 15.71 ly (4.817 pc) of the Sun.[12]

Gliese 832 emits X-rays.[13] 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.[14]

Planetary system

Gliese 832 hosts two known planets.

The Gliese 832 planetary system[15]
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 ≥0.62 MJ 3.46 3507±181 0.08±0.05 — —

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] The orbital solution of the planet was refined in 2011.[15]

In 2014, a second planet Gliese 832 c was discovered by astronomers at the University of New South Wales. This one is believed to be of super-Earth mass[11] and has since been given the scientific name Gliese 832 c.[11] It was announced to orbit in the optimistic habitable zone but outside the conservative habitable zone of its parent star.[16] The planet Gliese 832 c is believed to be in, or very close to, the right distance from its sun to allow liquid water to exist on its surface.[11]

The region between Gliese 832 b and Gliese 832 c is a zone where additional planets are possible.[17]

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.[18]

See also
  • List of nearest stars
  • List of extrasolar planets

Notes
  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
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Bailey, J.; Butler, R. P.; Tinney, C. G.; Jones, H. R. A.; O'Toole, S.; Carter, B. D.; Marcy, G. W. (2009). "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. S2CID 17172233.
  3. 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, S2CID 119181646.
  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. S2CID 119219274. Lay summary.
  7. Interpolated value from NASA Exoplanet Archive, per: Bessell, M. S. (1995). "The Temperature Scale for Cool Dwarfs". In Tinney, C. G. (ed.). The Bottom of the Main Sequence - and Beyond, Proceedings of the ESO Workshop. Springer-Verlag. p. 123. Bibcode:1995bmsb.conf..123B.
  8. Lindgren, Sara; Heiter, Ulrike (2017). "Metallicity determination of M dwarfs. Expanded parameter range in metallicity and effective temperature". Astronomy and Astrophysics. 604: A97. arXiv:1705.08785. Bibcode:2017A&A...604A..97L. doi:10.1051/0004-6361/201730715. S2CID 119216828.
  9. Safonova, M.; Murthy, J.; Shchekinov, Yu. A. (2014). "Age Aspects of Habitability". International Journal of Astrobiology. 15 (2): 93–105. arXiv:1404.0641. Bibcode:2016IJAsB..15...93S. doi:10.1017/S1473550415000208. S2CID 20205600.
  10. "Gliese 832". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-09-23.
  11. "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
  12. 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, S2CID 59039482, A35.
  13. 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.
  14. Fontenla, J. M.; Linsky, Jeffrey L.; Witbrod, Jesse; France, Kevin; Buccino, A.; Mauas, Pablo; Vietes, Mariela; Walkowicz, Lucianne M. (2016), SEMI-EMPIRICAL MODELING OF THE PHOTOSPHERE, CHROMOSPHERE, TRANSITION REGION, AND CORONA OF THE M-DWARF HOST STAR GJ 832, arXiv:1608.00934
  15. Bonfils, X.; Delfosse, X.; Udry, S.; Forveille, T.; Mayor, M.; Perrier, C.; Bouchy, F.; Gillon, M.; Lovis, C.; Pepe, F.; Queloz, D.; Santos, N. C.; Ségransan, D.; Bertaux, J. -L. (2011), The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample, arXiv:1111.5019, doi:10.1051/0004-6361/201014704, S2CID 119288366
  16. 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". The Astrophysical Journal. 1406 (2): 5587. arXiv:1406.5587. Bibcode:2014ApJ...791..114W. doi:10.1088/0004-637X/791/2/114. S2CID 12157837.
  17. Satyal, S.; Griffith, J.; Musielak, Z. E. (2016), "Dynamics of a Probable Earth-mass Planet in GJ 832 System", The Astrophysical Journal, 845 (2): 106, arXiv:1604.04544, doi:10.3847/1538-4357/aa80e2, S2CID 118663957
  18. 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. S2CID 53704989.

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