HD 171028 is a star with an exoplanet companion in the equatorial constellation of Ophiuchus. With an apparent visual magnitude of 8.3,[2] it is too faint to be readily visible with the naked eye. Unlike most planet-harboring stars, it does not have a Hipparcos number. The star is located at a distance of approximately 365 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +13.5 km/s.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 18h 32m 15.4933s[1] |
| Declination | 06° 56′ 44.6858″[1] |
| Apparent magnitude (V) | 8.301[2] |
| Characteristics | |
| Spectral type | G0[3] |
| B−V color index | 0.61[3] |
| Astrometry | |
| Radial velocity (Rv) | +13.48±0.28[1] km/s |
| Proper motion (μ) | RA: −42.869±0.084[1] mas/yr Dec.: −14.705±0.077[1] mas/yr |
| Parallax (π) | 8.9274 ± 0.0497 mas[1] |
| Distance | 365 ± 2 ly (112.0 ± 0.6 pc) |
| Details | |
| Mass | 1.01±0.06[2] M☉ |
| Radius | 2.42+0.01 −0.03[1] R☉ |
| Luminosity | 5.406+0.042 −0.041[1] L☉ |
| Surface gravity (log g) | 3.84±0.03[2] cgs |
| Temperature | 5,671±16[2] K |
| Metallicity [Fe/H] | −0.48±0.01[2] dex |
| Rotational velocity (v sin i) | 2.3[3] km/s |
| Age | 4.890±0.229[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a yellow-hued G-type star of unknown luminosity class with a stellar classification of G0.[3] It is a metal-poor star belonging to the thin disk population.[6] HD 171028 is estimated to be nearly five billion years old and is spinning with a projected rotational velocity of 2.3 km/s.[3] It has the same mass as the Sun, but the radius is 2.4 times larger. The star is radiating 5.4[1] times the luminosity of the Sun from its photosphere at an effective temperature of 5,671 K.[2]
In the summer of 2007, a Jovian planetary companion was discovered by the HARPS planet search program using the radial velocity method.[3] This object is orbiting at a distance of 1.32 AU from the host star with a period of 1.5 years and an eccentricity (ovalness) of 0.59. Since the inclination of the orbit is unknown, only a minimum mass can be determined. This planet has at least double the mass of Jupiter.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.98 MJ | 1.32 | 550±3 | 0.59±0.01 | — | — |
See also
editReferences
edit- ^ a b c d e f g h i j 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.
- ^ a b c d e f g Sousa, S. G.; et al. (February 2011). "Spectroscopic characterization of a sample of metal-poor solar-type stars from the HARPS planet search program. Precise spectroscopic parameters and mass estimation". Astronomy and Astrophysics. 526: 11. arXiv:1012.1528. Bibcode:2011A&A...526A..99S. doi:10.1051/0004-6361/201015646. S2CID 118785170. A99.
- ^ a b c d e f Santos, N. C.; et al. (2007). "The HARPS search for southern extra-solar planets. XII. A giant planet orbiting the metal-poor star HD 171028". Astronomy and Astrophysics. 474 (2): 647–651. arXiv:0708.0954. Bibcode:2007A&A...474..647S. doi:10.1051/0004-6361:20078129. S2CID 73681862.
- ^ Costa Silva, A. R.; et al. (February 2020). "Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur". Astronomy & Astrophysics. 634: 10. arXiv:1912.08659. Bibcode:2020A&A...634A.136C. doi:10.1051/0004-6361/201936523. S2CID 209405391. A136.
- ^ "HD 171028". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-10-06.
- ^ Haywood, M. (May 2008). "A peculiarity of metal-poor stars with planets?". Astronomy and Astrophysics. 482 (2): 673–676. arXiv:0804.2954. Bibcode:2008A&A...482..673H. doi:10.1051/0004-6361:20079141. S2CID 16390388.
- ^ a b Santos, Nuno C.; et al. (2011), "The HARPS search for southern extrasolar planets XXV. Results from the metal-poor sample", Astronomy and Astrophysics, 526: A112, arXiv:1011.2094, Bibcode:2011A&A...526A.112S, doi:10.1051/0004-6361/201015494, S2CID 119106340