HD 86226
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Hydra
Right ascension 09h 56m 29.844s[1]
Declination –24° 05′ 57.80″[1]
Apparent magnitude (V) 7.93[2]
Characteristics
Spectral type G2V[3]
Apparent magnitude (B) 8.577[2]
Apparent magnitude (R) 7.71[2]
Apparent magnitude (J) 6.839±0.019[2]
Apparent magnitude (H) 6.577±0.034[2]
Apparent magnitude (K) 6.463±0.023[2]
B−V color index 0.647±0.014[2]
V−R color index 0.22[4]
Astrometry
Radial velocity (Rv)+19.56±0.19[4] km/s
Proper motion (μ) RA: –177.127 mas/yr[1]
Dec.: +47.099 mas/yr[1]
Parallax (π)21.9301 ± 0.0267 mas[1]
Distance148.7 ± 0.2 ly
(45.60 ± 0.06 pc)
Absolute magnitude (MV)4.66[2]
Details[5]
Mass1.019+0.061
−0.066 M☉
Radius1.053+0.026
−0.026 R☉
Luminosity1.180+0.036
−0.029 L☉
Surface gravity (log g)4.400+0.029
−0.032 cgs
Temperature5863±88 K
Metallicity [Fe/H]0.018+0.057
−0.043 dex
Rotational velocity (v sin i)3.6[6] km/s
Age4.6+3.7
−2.7 Gyr
Other designations
CD–23°8866, HD 86226, HIP 48739, SAO 178205, PPM 256971[7]
Database references
SIMBADdata
Exoplanet Archivedata

HD 86226 is a star with a pair of orbiting exoplanet companions, found in the constellation of Hydra. With an apparent visual magnitude of 7.93,[2] it is too dim to be visible with the naked eye. The distance to this system has been determined by the parallax method, yielding a range of 149 light years. It is receding with a heliocentric radial velocity of +19.6 km/s.[4] A survey in 2015 has ruled out the existence of any stellar companions at projected distances above 12 astronomical units.[8]

This is an ordinary G-type main-sequence star with a stellar classification of G2V.[3] It is similar in size, mass, and composition to the Sun,[5] although it isn't considered a solar twin.[9] The age is about the same; roughly 4.6 billion years old. The star is radiating 18% greater luminosity (compared to the Sun) from its photosphere at an effective temperature of 5,863 K.[5] It is spinning with a projected rotational velocity of 3.6 km/s.[6]

As of 2014, Radio emission at a frequency of 150 MHz has been tentatively detected from the proximity of this system, although it is not clear whether the star or a satellite orbiting a rapidly rotating planet is the source.[10]

Planetary system

Due to the periodic spectrum shifts when it had when placed under a Doppler test, 13 Magellan Doppler Velocity observations were made of an object found near the star. The object discovered in 2010 had a Keplerian orbit, was declared an exoplanet and dubbed HD 86226 b.[11] A hot Super-Earth planet called HD 86226 c was discovered in 2020.[5] It may be undergoing considerable atmospheric mass loss.[12]

The HD 86226 planetary system[5][13]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
c 7.25+1.19
−1.12 M🜨		 0.049±0.001 3.98442±0.00018 0.075+0.065
−0.048		 86.45+0.26
−0.16°		 2.16±0.08 R🜨
b 0.45+0.04
−0.05 MJ		 2.73±0.06 1628+22
−21		 0.059+0.062
−0.039		 — —

See also

References

  1. 1 2 3 4 5 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. 1 2 3 4 5 6 7 8 9 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. 1 2 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H
  4. 1 2 3 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.
  5. 1 2 3 4 5 Teske, Johanna; et al. (2020). "TESS Reveals a Short-period Sub-Neptune Sibling (HD 86226c) to a Known Long-period Giant Planet". The Astronomical Journal. 160 (2): 96. arXiv:2007.13927. Bibcode:2020AJ....160...96T. doi:10.3847/1538-3881/ab9f95. S2CID 220830943.
  6. 1 2 Llorente de Andrés, F.; et al. (October 2021). "The evolution of lithium in FGK dwarf stars. The lithium-rotation connection and the Li desert". Astronomy and Astrophysics. 654: A137. arXiv:2108.05852. Bibcode:2021A&A...654A.137L. doi:10.1051/0004-6361/202141339. ISSN 0004-6361.
  7. ↑ "HD 86226". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-02-10.
  8. ↑ Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 450 (3): 3127–3136. Bibcode:2015MNRAS.450.3127M. doi:10.1093/mnras/stv771. hdl:1887/49340. Retrieved 19 June 2020.
  9. ↑ Datson, Juliet; et al. (February 2015). "Spectroscopic study of solar twins and analogues". Astronomy & Astrophysics. 574: 12. arXiv:1412.8168. Bibcode:2015A&A...574A.124D. doi:10.1051/0004-6361/201425000. S2CID 53708062. A124.{{cite journal}}: CS1 maint: postscript (link)
  10. ↑ Sirothia, S. K.; et al. (February 2014). "Search for 150 MHz radio emission from extrasolar planets in the TIFR GMRT Sky Survey". Astronomy & Astrophysics. 562: 9. Bibcode:2014A&A...562A.108S. doi:10.1051/0004-6361/201321571. A108.
  11. ↑ Arriagada, Pamela; et al. (2010). "Five Long-period Extrasolar Planets in Eccentric orbits from the Magellan Planet Search Program". The Astrophysical Journal. 711 (2): 1229–1235. arXiv:1001.4093. Bibcode:2010ApJ...711.1229A. doi:10.1088/0004-637X/711/2/1229. S2CID 118682009.
  12. ↑ Gupta, Akash; Schlichting, Hilke E. (July 2021). "Caught in the act: core-powered mass-loss predictions for observing atmospheric escape". Monthly Notices of the Royal Astronomical Society. 504 (3): 4634–4648. arXiv:2103.08785. Bibcode:2021MNRAS.504.4634G. doi:10.1093/mnras/stab1128.
  13. ↑ Marmier, M.; et al. (March 2013). "The CORALIE survey for southern extrasolar planets XVII. New and updated long period and massive planets". Astronomy and Astrophysics. 551: A90. arXiv:1211.6444. Bibcode:2013A&A...551A..90M. doi:10.1051/0004-6361/201219639. S2CID 59467665.
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