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[2] mas
Distance149.1 ± 0.1 ly
(45.72 ± 0.04 pc)
Details[3][4]
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[5]
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).[6]

Planetary system

In 2012, one planet, named HD 77338b, was discovered by the radial velocity method on a tight orbit with uncertain eccentricity.[7] Its equilibrium temperature is 954.8 K.[8]

The HD 77338 planetary system[9][7]
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). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics (in press). arXiv:2012.01533. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
  3. Masses, Oxygen and Carbon abundances in CHEPS dwarf stars, 2018, arXiv:1811.05011
  4. The metal rich abundance pattern – spectroscopic properties and abundances for 107 main-sequence stars, 2017, arXiv:1703.05077
  5. Rotation periods of late-type dwarf stars from time-series high-resolution spectroscopy of chromospheric indicators, 2015, arXiv:1506.08039
  6. Abundances in the atmosphere of the metal-rich planet-host star HD 77338, 2015, arXiv:1505.05843
  7. A hot Uranus orbiting the super metal-rich star HD77338 and the Metallicity - Mass Connection, 2012, arXiv:1207.1012
  8. 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
  9. ACCURATE, EMPIRICAL RADII AND MASSES OF PLANETS AND THEIR HOST STARS WITH GAIA PARALLAXES, 2016, arXiv:1609.04389

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