HD 77338

HD 77338 is a K-type subgiant star which has recently exhausted its hydrogen fuel and has started to expand. Its surface temperature is 5315 K.[3] HD 77338 is enriched in its concentration of heavy elements compared to the Sun, with a metallicity Fe/H index of 0.16 but is much older at an age of 9.5 billion years.[3]

HD 77338
Observation data
Epoch J2000      Equinox J2000
Constellation Pyxis
Right ascension 09h 01m 12.4938s[1]
Declination −25° 31′ 37.4333″[1]
Apparent magnitude (V) 8.59
Characteristics
Evolutionary stage subgiant star
Spectral type K0IV
Astrometry
Radial velocity (Rv)8.209[2] km/s
Proper motion (μ) RA: 40.095[2] mas/yr
Dec.: -271.640[2] mas/yr
Parallax (π)21.8739 ± 0.0192 mas[2]
Distance149.1 ± 0.1 ly
(45.72 ± 0.04 pc)
Details[3]
Mass0.942 M☉
Luminosity0.708 L☉
Surface gravity (log g)4.42 cgs
Temperature5315 K
Metallicity [Fe/H]0.16 dex
Rotation33.4±10.0 d[4]
Rotational velocity (v sin i)1.3 km/s
Age9.5 Gyr
Other designations
CD−25 6797, HIP 44291, TYC 6589-761-1, 2MASS J09011248-2531371[1]
Database references
SIMBADdata

HD 77338 is unusually enriched in heavy elements for a star of its age. The anomalously high abundance of ions of manganese may indicate the star has recently passed through the common shell stage (engulfed a planet).[5]

Planetary system

In 2012, one planet, named HD 77338b, was discovered by the radial velocity method on a tight orbit with uncertain eccentricity.[6] Its equilibrium temperature is 954.8 K.[7]

The HD 77338 planetary system[8][6]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥15.9+4.7
−5.3 M🜨		 0.0614+0.0031
−0.0034		 5.73610±0.0015 0.09+0.22
−0.09		 — —

References
  1. "HD 77338". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-19.
  2. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. Pavlenko, Y. V.; Kaminsky, B. M.; Jenkins, J. S.; Ivanyuk, O. M.; Jones, H. R. A.; Lyubchik, Y. P. (2019), "Masses, oxygen, and carbon abundances in CHEPS dwarf stars", Astronomy & Astrophysics, 621: A112, arXiv:1811.05011, Bibcode:2019A&A...621A.112P, doi:10.1051/0004-6361/201834138, S2CID 119103484
  4. Suárez Mascareño, A.; Rebolo, R.; González Hernández, J. I.; Esposito, M. (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
  5. Kushniruk, I. O.; Pavlenko, Ya. V.; Jenkins, J. S.; Jones, H. R. A. (2015), Abundances in the atmosphere of the metal-rich planet-host star HD 77338, arXiv:1505.05843
  6. Jenkins, J. S.; Jones, H. R. A.; Tuomi, M.; Murgas, F.; Hoyer, S.; Jones, M. I.; Barnes, J. R.; Pavlenko, Y. V.; Ivanyuk, O.; Rojo, P.; Jordán, A.; Day-Jones, A. C.; Ruiz, M. T.; Pinfield, D. J. (2013), "A Hot Uranus Orbiting the Super Metal-Rich Star Hd 77338 and the Metallicity-Mass Connection", The Astrophysical Journal, 766 (2): 67, arXiv:1207.1012, Bibcode:2013ApJ...766...67J, doi:10.1088/0004-637X/766/2/67, S2CID 16971803
  7. HD 77338 b is an exoplanet orbiting the star HD 77338, located about 149.3 light-years (45.8 pc) away from Solar System. Its discovery was publicly announced on 2012
  8. Stassun, Keivan G.; Collins, Karen A.; Gaudi, B. Scott (2017), "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes", The Astronomical Journal, 153 (3): 136, arXiv:1609.04389, Bibcode:2017AJ....153..136S, doi:10.3847/1538-3881/aa5df3, S2CID 119219062
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