| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 01 06 02.050 |
| Declination | –22° 27′ 11.35″ |
| Apparent magnitude (V) | 10.16 |
| Characteristics | |
| Spectral type | K5V |
| Apparent magnitude (B) | 11.238 |
| B−V color index | 1.078±0.001 |
| Astrometry | |
| Radial velocity (Rv) | 15.28±0.23 km/s |
| Proper motion (μ) | RA: 203.818±0.025 mas/yr Dec.: −106.926±0.032 mas/yr |
| Parallax (π) | 19.3199 ± 0.0198 mas |
| Distance | 168.8 ± 0.2 ly (51.76 ± 0.05 pc) |
| Absolute magnitude (MV) | 7.11 |
| Details | |
| Mass | 0.75±0.01 M☉ |
| Radius | 0.69±0.02 R☉ |
| Luminosity | 0.19±0.01 L☉ |
| Surface gravity (log g) | 4.63±0.02 cgs |
| Temperature | 4,571±14 K |
| Metallicity | 0.10±0.07 dex |
| Rotation | 42.3 days |
| Age | 4.5±3.2 Gyr |
| Other designations | |
| CD–23°395, HIP 5158, SAO 166798, PPM 243575, LTT 617, NLTT 3632, 2MASS J01060202-2227111 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HIP 5158 is a star with a pair of orbiting substellar companions, located in the equatorial constellation of Cetus, the whale. It has the older designation CD-23 395, which is derived from the Cordoba Durchmusterung catalogue of southern stars. Based on parallax measurements, it is located 169 light years from the Sun. It has an absolute magnitude of 7.11, but at that distance the star has an apparent visual magnitude of 10.16, which is too dim to be visible to the naked eye. The system is receding with a radial velocity of 15.3 km/s, and it has a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.205″·yr.
The spectrum of HIP 5158 matches an ordinary K-type main-sequence star, an orange dwarf, with a stellar classification of K5V. The age of this star is poorly constrained, but it appears to be comparable to the Sun. It is spinning slowly with a rotation period of around 42.3 days. Based on the abundance of iron, this star appears metal rich, having concentration of heavy elements equal to 125% of solar abundance. It has 75% of the mass of the Sun and 60% of the Sun's radius. The star is radiating just 19% of the luminosity of the Sun from its photosphere at an effective temperature of 4,571 K.
Planetary system
In 2009, a gas giant planet HIP 5158 b was found in orbit around the star. The quadratic drift in the radial velocities did indicate the presence of an additional outer planet in the system, which was confirmed in 2011. The large uncertainty in the mass of HIP 5158 c leaves in question whether this is an exoplanet or a brown dwarf.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.42 MJ | 0.89 | 345.72 ± 5.37 | 0.52 ± 0.08 | — | — |
| c | ≥15.04 MJ | 7.7±1.88 | 9,018±3181 | 0.14±0.1 | — | — |
See also
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.
- ^ 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.
- ^ Lo Curto, G.; et al. (2015). "The HARPS search for southern extra-solar planets. XXII. Multiple planet systems from the HARPS volume limited sample". Astronomy and Astrophysics. 512. A48. Bibcode:2010A&A...512A..48L. doi:10.1051/0004-6361/200913523.
- ^ 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.
- ^ Bonfanti, A.; et al. (2016). "Age consistency between exoplanet hosts and field stars". Astronomy & Astrophysics. 585: 14. arXiv:1511.01744. Bibcode:2016A&A...585A...5B. doi:10.1051/0004-6361/201527297. S2CID 53971692. A5.
- ^ "CD−23 395". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-11-10.
- Luyten, W. J. (June 1995). "NLTT Catalogue (Luyten, 1979)". VizieR Online Data Catalog. Bibcode:1995yCat.1098....0L.
- ^ Feroz, F.; et al. (2011). "Bayesian evidence for two companions orbiting HIP 5158". Monthly Notices of the Royal Astronomical Society: Letters. 416 (1): L104 – L108. arXiv:1105.1150. Bibcode:2011MNRAS.416L.104F. doi:10.1111/j.1745-3933.2011.01109.x. S2CID 118517956.
