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by | Mar 15, 2018 | Taxus Baccata

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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]

Planetary system

Gliese 832 hosts one known planet, with a second planet having been refuted in 2022.[6]

The Gliese 832 planetary system[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° 		—

Gliese 832 b

Main article: Gliese 832 b

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.[13] In 2023, an astrometric detection of the planet was announced, determining its inclination and revealing a true mass 80% the mass of Jupiter.[12]

Gliese 832 c

Gliese 832 c was 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.[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.[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.[15]

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

  1. ^ 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. ^ a b c d e f g Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c d e f 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. ^ 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, S2CID 119181646.
  4. ^ a b c d Pineda, J. Sebastian; Youngblood, Allison; France, Kevin (September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal. 918 (1): 23. arXiv:2106.07656. Bibcode:2021ApJ...918...40P. doi:10.3847/1538-4357/ac0aea. S2CID 235435757. 40.
  5. ^ 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. Archived from the original on 2021-01-23. Retrieved 2018-09-03.
  6. ^ a b c d e Gorrini, P.; Astudillo-Defru, N.; et al. (August 2022). "Detailed stellar activity analysis and modelling of GJ 832: Reassessment of the putative habitable zone planet GJ 832c". Astronomy & Astrophysics. 664: A64. arXiv:2206.07552. Bibcode:2022A&A...664A..64G. doi:10.1051/0004-6361/202243063. S2CID 249674385.
  7. ^ "Gliese 832". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-09-23.
  8. ^ a b c d "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 Archived 2018-07-12 at the Wayback Machine
  9. ^ 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.
  10. ^ 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.
  11. ^ Fontenla, J. M.; Linsky, Jeffrey L.; Garrison, Jesse; France, Kevin; Buccino, A.; Mauas, Pablo; Vietes, Mariela; Walkowicz, Lucianne M. (2016). "Semi-Empirical Modeling of the Photosphere, Chromopshere, Transition Region, and Corona of the M-Dwarf Host Star Gj 832". The Astrophysical Journal. 830 (2): 154. arXiv:1608.00934. Bibcode:2016ApJ...830..154F. doi:10.3847/0004-637X/830/2/154. hdl:11336/21732. S2CID 119279568.
  12. ^ a b Xiao, Guang-Yao; Liu, Yu-Juan; et al. (March 2023). "The Masses of a Sample of Radial-Velocity Exoplanets with Astrometric Measurements". Research in Astronomy and Astrophysics. 23 (5). arXiv:2303.12409. Bibcode:2023RAA....23e5022X. doi:10.1088/1674-4527/accb7e. S2CID 257663647.
  13. ^ Bonfils, Xavier; Delfosse, Xavier; Udry, Stéphane; Forveille, Thierry; Mayor, Michel; Perrier, Christian; Bouchy, François; Gillon, Michaël; Lovis, Christophe; Pepe, Francesco; Queloz, Didier; Santos, Nuno C.; Ségransan, Damien; Bertaux, Jean-Loup (2011). "The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample". Astronomy and Astrophysics. 549: A109. arXiv:1111.5019. Bibcode:2013A&A...549A.109B. doi:10.1051/0004-6361/201014704. S2CID 119288366.
  14. ^ 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.
  15. ^ 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
  16. ^ 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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