Astronomy:HD 106315
Coordinates: 
12h 13m 53.3962s, −00° 23′ 36.5534″
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Virgo |
| Right ascension | 12h 13m 53.3962s[1] |
| Declination | −00° 23′ 36.5534″[1] |
| Apparent magnitude (V) | 8.951[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | F5V[3] |
| B−V color index | 0.45[2] |
| Astrometry | |
| Radial velocity (Rv) | −3.2±0.3[1] km/s |
| Proper motion (μ) | RA: −2.36±0.03[1] mas/yr Dec.: 11.943±0.019[1] mas/yr |
| Parallax (π) | 9.1725 ± 0.0221[1] mas |
| Distance | 355.6 ± 0.9 ly (109.0 ± 0.3 pc) |
| Details | |
| Mass | 1.105+0.028−0.036[4] M☉ |
| Radius | 1.286+0.049−0.040[4] R☉ |
| Luminosity | 2.432+0.057−0.234[4] L☉ |
| Surface gravity (log g) | 4.261+0.027−0.024[4] cgs |
| Temperature | 6,300±37[4] K |
| Metallicity [Fe/H] | −0.268+0.060−0.071[4] dex |
| Rotation | 4.78±0.15[5] |
| Rotational velocity (v sin i) | 12.9±0.4[4] km/s |
| Age | 3.987+0.802−0.516[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 106315, or K2-109, is a single star with a pair of close-orbiting exoplanets, located in the constellation of Virgo. Based on parallax measurements, this system lies at a distance of 356 light years from the Sun.[1] At that range, the star is too faint to be seen with the naked eye, as it has an apparent visual magnitude of 8.95.[2] But it is slowly drifting closer with a radial velocity of −3 km/s.[1] (As of 2020), multiplicity surveys have not detected any stellar companions to HD 106315.[5]
The spectrum of HD 106315 presents as an ordinary F-type main-sequence star with a stellar classification of F5V,[3] indicating it is generating energy through hydrogen fusion at its core. It is estimated to be roughly four[4] billion years old but is spinning quickly with a rotation period of 5 days. The star is relatively metal-poor, having 60% of solar concentration of iron. It has only a low level of magnetic activity in its chromosphere, showing a minimal level of star spot coverage.[5] The star has 11% more mass and a 29% larger radius than the Sun. It is radiating 2.4 times the luminosity of the Sun from its photosphere at an effective temperature of 6,300 K.[4]
Planetary system
Two planets were detected by the transit method in 2017,[4] using data from the extended Kepler mission (K2). Their large planetary radii imply both planets have a massive steam atmosphere for planet b and hydrogen-helium atmosphere for planet c.[5] The planetary system of HD 106315 is rather unstable and current planetary orbits are the outcome of violent dynamical history,[7] strongly affected by relativistic effects.[8] The orbits of planets are nearly coplanar, and orbit of c is well aligned with the equatorial plane of the star, misalignment been equal to -10+3.6−3.8°.[9]
Since 2017, a third outer planet with mass above 45M⊕ is suspected to exist in the system.[2]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 10.5±3.1[5] M⊕ | 0.0924+0.0011−0.0012 | 9.55288±0.00021 | 0 | 87.6+3.0−1.7° | 2.4±0.2 R⊕ |
| c | 12.0±3.8[5] M⊕ | 0.1565+0.0019−0.0020 | 21.05652±0.00012 | 0 | 88.89+0.69−0.51° | 4.379±0.086 R⊕ |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Crossfield, Ian J. M. et al. (2017). "Two Small Transiting Planets and a Possible Third Body Orbiting HD 106315". The Astronomical Journal 153 (6): 255. doi:10.3847/1538-3881/aa6e01. Bibcode: 2017AJ....153..255C.
- ↑ 3.0 3.1 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey 5. Bibcode: 1999MSS...C05....0H.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Rodriguez, Joseph E. et al. (2017). "A Multi-planet System Transiting the V = 9 Rapidly Rotating F-Star HD 106315". The Astronomical Journal 153 (6): 256. doi:10.3847/1538-3881/aa6dfb. Bibcode: 2017AJ....153..256R.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Kosiarek, Molly R. et al. (2021). "Physical Parameters of the Multiplanet Systems HD 106315 and GJ 9827". The Astronomical Journal 161 (1): 47. doi:10.3847/1538-3881/abca39. Bibcode: 2021AJ....161...47K.
- ↑ "HD 106315". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+106315.
- ↑ Turrini, D. et al. (2020). "Normalized angular momentum deficit: A tool for comparing the violence of the dynamical histories of planetary systems". Astronomy and Astrophysics 636: A53. doi:10.1051/0004-6361/201936301. Bibcode: 2020A&A...636A..53T.
- ↑ Marzari, F.; Nagasawa, M. (2020). "Secular evolution of close-in planets: The effects of general relativity". Monthly Notices of the Royal Astronomical Society 493 (1): 427. doi:10.1093/mnras/staa271. Bibcode: 2020MNRAS.493..427M.
- ↑ Zhou, George et al. (2018). "The Warm Neptunes around HD 106315 Have Low Stellar Obliquities". The Astronomical Journal 156 (3): 93. doi:10.3847/1538-3881/aad085. Bibcode: 2018AJ....156...93Z.
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