HIP 86081 / Bibha
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Sextans
Right ascension 09h 56m 05.91853s[1]
Declination −03° 48′ 30.3233″[1]
Apparent magnitude (V) 8.73[2]
Characteristics
Spectral type G1V[3]
B−V color index 0.664±0.026[2]
Astrometry
Radial velocity (Rv)+30.88±0.27[2] km/s
Proper motion (μ) RA: −67.001±0.079[1] mas/yr
Dec.: 15.999±0.076[1] mas/yr
Parallax (π)9.5928 ± 0.0509 mas[1]
Distance340 ± 2 ly
(104.2 ± 0.6 pc)
Absolute magnitude (MV)3.86[2]
Details[4]
Mass1.21±0.28 M☉
Radius1.46±0.14 R☉
Luminosity2.941[1] L☉
Surface gravity (log g)4.25[5] cgs
Temperature5,973[1] K
Metallicity [Fe/H]+0.22 dex
Rotational velocity (v sin i)5.0[5] km/s
Age3.61±0.86 Gyr
Other designations
BD−03 2815, HD 86081, HIP 48711, SAO 137236[6]
Database references
SIMBADdata

HD 86081 is a yellow-hued star in the equatorial constellation of Sextans. It has the proper name Bibha, after Indian physicist Bibha Chowdhuri. The name was suggested in the NameExoWorlds competition by Ananyo Bhattacharya, a mechanical engineering student of the Sardar Vallabhbhai National Institute of Technology Surat.[7] With an apparent visual magnitude of 8.73,[2] this star is too dim to be viewed with the naked eye but can be seen with a small telescope. It is located at a distance of approximately 340 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +31 km/s.[2]

Characteristics

The stellar classification of this star is G1V,[3] which indicates this is a G-type main-sequence star that, like the Sun, is generating energy through hydrogen fusion at its core. It is bigger and more massive than the Sun at 1.46 and 1.21 solar units respectively. The star is an estimated 3.6[4] billion years old and is spinning with a projected rotational velocity of 5 km/s.[5] It is chromospherically inactive, with no emission seen in the core of the Ca II H and K lines.[8] HD 86081 is radiating 2.9[1] times the luminosity of the Sun from its photosphere at an effective temperature of 5,973 K.[1]

Planetary system

Monitoring of this star for radial velocity variations began in November 2005 and the first companion was discovered on April 17, 2006.[8] This hot Jupiter is orbiting just 5,180,000 km from the host star and has an orbital period of 2.1 days, one of the shortest periods ever discovered by this technique.[4] The separation of this exoplant is sufficiently low that it may have sped up the star's rotation through tidal interaction.[9] HD 86081 shows no evidence of planetary transits in spite of a 17.6% transit probability.[8] There is a linear trend in the star's radial velocity measurements that may be an indicator of additional unseen companions.[4]

The HD 86081 planetary system[4]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b / Santamasa ≥1.48±0.23 MJ 0.0346±0.0027 2.1378431±0.0000031 0.0119±0.0047 — —

See also

References

  1. 1 2 3 4 5 6 7 8 9 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. 1 2 3 4 5 6 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, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  4. 1 2 3 4 5 Ment, Kristo; et al. (2018). "Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810". The Astronomical Journal. 156 (5). 213. arXiv:1809.01228. Bibcode:2018AJ....156..213M. doi:10.3847/1538-3881/aae1f5. S2CID 119243619.
  5. 1 2 3 Gonzalez, G.; et al. (2010). "Parent stars of extrasolar planets - X. Lithium abundances and v sini revisited". Monthly Notices of the Royal Astronomical Society. 403 (3): 1368. arXiv:0912.1621. Bibcode:2010MNRAS.403.1368G. doi:10.1111/j.1365-2966.2009.16195.x. S2CID 118520284.
  6. ↑ "HD 86081". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-12-28.
  7. ↑ "Approved names". NameExoworlds. Retrieved 2020-01-02.
  8. 1 2 3 Johnson, John Asher; et al. (2006). "The N2K Consortium. VI. Doppler Shifts without Templates and Three New Short-Period Planets". The Astrophysical Journal. 647 (1): 600–611. arXiv:astro-ph/0604348. Bibcode:2006ApJ...647..600J. doi:10.1086/505173. S2CID 12421834.
  9. ↑ Pont, Frédéric (July 2009). "Empirical evidence for tidal spin-up in transiting planetary systems". Monthly Notices of the Royal Astronomical Society. 396 (3): 1789–1796. arXiv:0812.1463. Bibcode:2009MNRAS.396.1789P. doi:10.1111/j.1365-2966.2009.14868.x. S2CID 10975188.
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