BG Indi, also known as κ1 Indi (Kappa1 Indi) is a multiple star system in the southern constellation of Indus. Its average apparent magnitude is 6.141,[3] meaning it can only be seen by the naked eye under exceptionally good viewing conditions. Stellar parallax measurements by Gaia put the system at about 166 light-years (51 parsecs) away.[2]

Nomenclature

The star system is most commonly known as BG Indi. BG Indi is its variable star designation, a unique name given to variable stars based on its constellation and when it was discovered to be a variable.[4] It also has the name κ1 Indi (Latinized to Kappa1 Indi), which is its Bayer designation.[6]

Properties

BG Indi consists of four stars in two compact, orbiting pairs. The brighter pair is known as BG Indi A, and consists of two F-type main-sequence stars Aa and Ab. As F-type stars, they are more massive, larger, and hotter than the Sun,[1] and with a metallicity of −0.2 ± 0.1, it is less metal-rich than the Sun. BG Indi is about 2.65 billion years old, and is just starting to leave the main sequence.[8]

BG Indi Aa and Ab orbit each other on a circular orbit, with a period of 1.46 days. Periodically, one star passes in front of the other, blocking its light. Therefore, the apparent magnitude varies from 6.11 to 6.36.[4] Its status as an eclipsing binary was confirmed by J. Manfroid and G. Mathys in 1984.[5]

The other two stars, BG Indi Ba and Bb, form the pair BG Indi B. Both are less massive than the Sun, and orbit each other on a tighter orbit with a period of 0.53 days. Collectively, BG Indi A and B orbit each other with a period of 720.9 days with a moderate eccentricity of 0.209. All three orbits are likely to be more or less coplanar. BG Indi is the nearest quadruple star system consisting of two eclipsing binaries.[1]

Notes

  1. ^ a b This refers to the epoch of primary transit.

References

  1. ^ a b c d e f g h i Borkovits, T.; Rappaport, S. A.; Maxted, P F L.; Terentev, I.; Omohundro, M.; Gagliano, R.; Jacobs, T.; Kristiansen, M. H.; Lacourse, D.; Schwengeler, H. M.; Vanderburg, A.; Blackford, M. G. (2021). "BG Ind: The nearest doubly eclipsing, compact hierarchical quadruple system". Monthly Notices of the Royal Astronomical Society. 503 (3): 3759–3774. arXiv:2103.00925. doi:10.1093/mnras/stab621.
  2. ^ a b c d e 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.
  3. ^ a b Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27 – L30. Bibcode:2000A&A...355L..27H.
  4. ^ a b c Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  5. ^ a b Manfroid, J.; Mathys, G. (1984). "The Bright Eclipsing Binary HD 208496". Information Bulletin on Variable Stars. 2616 (2616): 1. Bibcode:1984IBVS.2616....1M.
  6. ^ a b c "* kap01 Ind". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-07-17.
  7. ^ Holmberg, J.; Nordström, B.; Andersen, J. (2007). "The Geneva-Copenhagen survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk". Astronomy and Astrophysics. 475 (2): 519. arXiv:0707.1891. Bibcode:2007A&A...475..519H. doi:10.1051/0004-6361:20077221. S2CID 119054949.
  8. ^ Rozyczka, M.; Kaluzny, J.; Pych, W.; Konacki, M.; Małek, K.; Mankiewicz, L.; Sokołowski, M.; Żarnecki, A. F. (2011). "Absolute properties of BG Ind - a bright F3 system just leaving the main sequence". Monthly Notices of the Royal Astronomical Society. 414 (3): 2479–2485. arXiv:1010.1355. Bibcode:2011MNRAS.414.2479R. doi:10.1111/j.1365-2966.2011.18567.x. S2CID 118422112.
Allikas: https://en.wikipedia.org/wiki/BG_Indi
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