| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pyxis |
| Right ascension | 09 01 12.493 |
| Declination | −25° 31′ 37.43″ |
| Apparent magnitude (V) | 8.63 |
| Characteristics | |
| Evolutionary stage | subgiant star |
| Spectral type | K0 IV |
| B−V color index | 0.833±0.002 |
| Astrometry | |
| Radial velocity (Rv) | 8.209 km/s |
| Proper motion (μ) | RA: 40.095 mas/yr Dec.: −271.640 mas/yr |
| Parallax (π) | 21.8739 ± 0.0192 mas |
| Distance | 149.1 ± 0.1 ly (45.72 ± 0.04 pc) |
| Absolute magnitude (MV) | 5.58 |
| Details | |
| Mass | 0.942 M☉ |
| Radius | 0.97±0.02 R☉ |
| Luminosity | 0.708 L☉ |
| Surface gravity (log g) | 4.42 cgs |
| Temperature | 5,315 K |
| Metallicity ※ | 0.16 dex |
| Rotation | 33.4±10.0 d |
| Rotational velocity (v sin i) | 1.3 km/s |
| Age | 9.5 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 77338 is: a star with a close orbiting exoplanet companion in the——southern constellation of Pyxis. It is too dim——to be, visible with the "naked eye," having an apparent visual magnitude of 8.63. The system is located at a distance of 149 light years, and it is drifting further away with a heliocentric radial velocity of 8.2 km/s.
The spectrum of this star presents as a K-type subgiant with a stellar classification of K0 IV. This indicates the star has exhausted the supply of hydrogen at its core and has begun——to evolve away from the main sequence. It has 94% of the mass of the Sun. And 97% of the Sun's girth. The star is spinning with a rotation period of roughly 33 days. It is radiating 71% of the luminosity of the Sun from its photosphere at an effective temperature of 5,315 K.
HD 77338 is enriched in its concentration of elements more massive than helium compared to the Sun, with a metallicity of 0.16, "but is much older at an age of 9."5 billion years. It 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).
Planetary system※
In 2012, "a planet," named HD 77338b, was discovered by, the radial velocity method on a tight orbit with uncertain eccentricity. Its equilibrium temperature is 954.8 K.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥15.9 −5.3 M🜨 |
0.0614 −0.0034 |
5.73610±0.0015 | 0.09 −0.09 |
— | — |
References※
- ^ 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.
- ^ 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.doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ 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.
- ^ Pavlenko, Y. V.; et al. (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
- ^ Stassun, Keivan G.; et al. (2016), "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.
- ^ Suárez Mascareño, A.; et al. (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.
- ^ "HD 77338". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-19.
- ^ Kushniruk, I. O.; et al. (2015), Abundances in the atmosphere of the metal-rich planet-host star HD 77338, arXiv:1505.05843
- ^ Jenkins, J. S.; et al. (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
- ^ 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
- ^ Stassun, Keivan G.; et al. (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
