Gliese 867

Gliese 867 is a quadruple star system located 29 light-years (8.9 parsecs) away in the constellation Aquarius. It is composed of two binary sub-systems, Gliese 867 A & B, also known by their variable star designations FK Aquarii and FL Aquarii. Gliese 867 is the third-nearest quadruple system, after Gliese 570 and Mu Herculis,[12] and the nearest such system where the primary star is a red dwarf.[6] There are two closer quintuple systems, V1054 Ophiuchi and Xi Ursae Majoris, the former composed entirely of red dwarfs.[12]

System

GJ 867 A (FK Aqr A)
Period = 4.1 d
GJ 867 C (FK Aqr B)
Sep = 216 au
GJ 867 B (FL Aqr A)
Period = 1.8 d
GJ 867 D (FL Aqr B)

Hierarchy of orbits in the Gliese 867 system

Gliese 867 A & B are separated by 24.5 arcseconds, corresponding to a projected distance of 216 AU. Both are spectroscopic binaries.[6] Gliese 867 A & B are both flare stars and BY Draconis variables.[7][8] They have been known to be flare stars since 1978.[13]

Gliese 867 A (FK Aquarii)

A light curve for FK Aquarii, plotted from TESS data.[14] The binary's orbital period is marked in red. The inset plot, adapted from Byrne et al. (1990),[15] shows a flare.

Gliese 867 A, also known as FK Aquarii, is a close binary orbiting every 4.1 days. The companion star is also called Gliese 867 C.[6] Both stars are red dwarfs around half the mass of the Sun.[10] The system has been known to be a spectroscopic binary since 1965, at that time referred to by its Durchmusterung designation BD−21°6267A.[16] It has also been characterized by astrometry from the Gaia space telescope.[17]

Both stars are magnetically active, and have strong dipolar magnetic fields resembling those found in lower-mass, fully convective red dwarfs. The primary star is the most massive red dwarf known to host this type of magnetic field as of 2024.[10]

Gliese 867 B (FL Aquarii)

A light curve showing flares on FL Aquarii, adapted from Doyle et al. (1986)[18]

Gliese 867 B, also known as FL Aquarii, is a close binary orbiting every 1.8 days. It was found to be a spectrosopic binary in 2014. The primary star is a red dwarf, while the companion, Gliese 867 D, has a minimum mass of only 61±7 Jupiter masses, and so may be a brown dwarf.[6]

See also

Notes

  1. ^ a b The two stars are assumed to be in synchronous rotation, so the rotation period is the same as the orbital period.

References

  1. ^ "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008.
  2. ^ a b c d 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.
  3. ^ a b Koen, C.; Kilkenny, D.; et al. (April 2010). "UBV(RI)C JHK observations of Hipparcos-selected nearby stars". Monthly Notices of the Royal Astronomical Society. 403 (4): 1949–1968. Bibcode:2010MNRAS.403.1949K. doi:10.1111/j.1365-2966.2009.16182.x.
  4. ^ a b c d e 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.
  5. ^ a b "V* FL Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 April 2025.
  6. ^ a b c d e f g h i Davison, Cassy L.; White, R. J.; et al. (February 2014). "The Closest M-dwarf Quadruple System to the Sun". The Astronomical Journal. 147 (2): 26. arXiv:1310.6761. Bibcode:2014AJ....147...26D. doi:10.1088/0004-6256/147/2/26.
  7. ^ a b "FK Aqr". General Catalog of Variable Stars - VizieR. Retrieved 10 April 2025.
  8. ^ a b "FL Aqr". General Catalog of Variable Stars - VizieR. Retrieved 10 April 2025.
  9. ^ a b "V* FK Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 April 2025.
  10. ^ a b c d e f g h i j k Tsvetkova, S.; Morin, J.; et al. (February 2024). "The large-scale magnetic field of the M dwarf double-line spectroscopic binary FK Aqr". Astronomy & Astrophysics. 682: A77. arXiv:2312.04247. Bibcode:2024A&A...682A..77T. doi:10.1051/0004-6361/202347604.
  11. ^ a b Houdebine, E. R. (April 2010). "Observation and modelling of main-sequence star chromospheres - X. Radiative budgets on Gl 867A and AU Mic (dM1e), and a two-component model chromosphere for Gl 205 (dM1)". Monthly Notices of the Royal Astronomical Society. 403 (4): 2157–2166. Bibcode:2010MNRAS.403.2157H. doi:10.1111/j.1365-2966.2010.16267.x.
  12. ^ a b Reylé, Céline; Jardine, Kevin; Fouqué, Pascal; Caballero, Jose A.; Smart, Richard L.; Sozzetti, Alessandro (30 April 2021). "The 10 parsec sample in the Gaia era". Astronomy & Astrophysics. 650: A201. arXiv:2104.14972. Bibcode:2021A&A...650A.201R. doi:10.1051/0004-6361/202140985. S2CID 233476431. Data available at https://gruze.org/10pc/ Archived 12 March 2023 at the Wayback Machine
  13. ^ Byrne, P. Brendan (April 1978). "Gliese 867 - a New Flare-Star System". Information Bulletin on Variable Stars. 1407 (1). Bibcode:1978IBVS.1407....1B.
  14. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 14 April 2025.
  15. ^ Byrne, P. B.; Butler, C. J.; Lyons, M. A. (September 1990). "Activity in late-type stars. VI. Optical photometry and UV spectroscopy of the active dMe star, FK Aquarii in late 1983". Astronomy and Astrophysics. 236: 455–460. Bibcode:1990A&A...236..455B. Retrieved 14 April 2025.
  16. ^ Herbig, G. H.; Moorhead, J. M. (February 1965). "BD-21°6267A: a New dMe Double-Line Spectroscopic Binary". Astrophysical Journal. 141: 649. Bibcode:1965ApJ...141..649H. doi:10.1086/148150.
  17. ^ Reylé, Céline; Jardine, Kevin; Fouqué, Pascal; Caballero, Jose A.; Smart, Richard L.; Sozzetti, Alessandro (6 February 2023). The 10 parsec sample in the Gaia era: First update. The 21st Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun. arXiv:2302.02810. Bibcode:2022csss.confE.218R. doi:10.5281/zenodo.7576096.
  18. ^ Doyle, J. G.; Byrne, P. B.; Butler, C. J. (February 1986). "Flare activity and BY-Draconis-type variability on the late-type dMe star Gliese 867 B". Astronomy and Astrophysics. 156: 283–288. Bibcode:1986A&A...156..283D. Retrieved 14 April 2025.

Further reading