HD 176693
HD 176693, also known as Kepler-408, is a F-type main-sequence star about 290 light-years away. The star is older than the Sun, at 7.15 billion years. It is slightly and uniformly[6] depleted in heavy elements compared to the Sun, having about 75% of the solar abundance of iron and other heavy elements.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco |
| Right ascension | 18h 59m 08.6847s[1] |
| Declination | 48° 25′ 23.5990″[1] |
| Apparent magnitude (V) | 8.83 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | F8V |
| B−V color index | 0.51[2] |
| Astrometry | |
| Radial velocity (Rv) | -54.9±0.2[3] km/s |
| Proper motion (μ) | RA: 4.704±0.013[3] mas/yr[3] Dec.: 9.263±0.016[3] mas/yr[3] |
| Parallax (π) | 11.218 ± 0.013 mas[3] |
| Distance | 290.7 ± 0.3 ly (89.1 ± 0.1 pc) |
| Details[4] | |
| Mass | 1.05±0.04 M☉ |
| Radius | 1.253±0.051 R☉ |
| Luminosity | 1.864[5] L☉ |
| Surface gravity (log g) | 4.318+0.08 −0.089 cgs |
| Temperature | 6080±65 K |
| Metallicity [Fe/H] | −0.138+0.043 −0.042 dex |
| Rotation | 12.89±0.19 d |
| Rotational velocity (v sin i) | 2.8±1.0 km/s |
| Age | 7.15±1.61[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 176693 is a chromospherically inactive star,[2] although there is weak evidence for tidal spin-up due to star-planet interaction.[7]
Multiplicity surveys did not detect any stellar companions to HD 176693 by 2016.[8]
Planetary system
In 2014, a transiting Sub-Earth planet b was detected on a tight 2.5 day orbit. Initially reported with a relatively low confidence of 97.9%,[9] it was confirmed in 2016.[10]
The planetary orbit is inclined to the equatorial plane of the star by 41.7+5.1
−3.5°. Such strong spin-orbit misalignment is unique for a sub-Earth transiting planet, and needs either additional giant planets in the system or a history of close stellar encounters to explain it.[4] The planet may also be a captured body originating from elsewhere.[11]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | — | — | 2.465024±0.000005 | — | 81.85±0.10° | 0.86±0.04 R🜨 |
References
- "Kepler-408", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 1 July 2021
- Booth, R. S.; Poppenhaeger, K.; Watson, C. A.; Silva Aguirre, V.; Stello, D.; Bruntt, H. (2020), "Chromospheric emission of solar-type stars with asteroseismic ages", Monthly Notices of the Royal Astronomical Society, 491: 455–467, arXiv:1910.12557, doi:10.1093/mnras/stz3039
- 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. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- Kamiaka, Shoya; Benomar, Othman; Suto, Yasushi; Dai, Fei; Masuda, Kento; Winn, Joshua N. (2019), "The Misaligned Orbit of the Earth-sized Planet Kepler-408b", The Astronomical Journal, 157 (4): 137, arXiv:1902.02057, Bibcode:2019AJ....157..137K, doi:10.3847/1538-3881/ab04a9, S2CID 118909208
- Brito, Ana; Lopes, Ilídio (2019), "The partial ionization zone of heavy elements in F-stars: A study on how it correlates with rotation", Monthly Notices of the Royal Astronomical Society, 488 (2): 1558–1571, arXiv:1906.12308, doi:10.1093/mnras/stz1804
- Ramírez, I.; Meléndez, J.; Acuña, L.; Spina, L.; Wang, H. S.; Asplund, M.; Yong, D.; Liu, F. (2020), "Detailed chemical compositions of planet-hosting stars – I. Exploration of possible planet signatures", Monthly Notices of the Royal Astronomical Society, 495 (4): 3961–3973, arXiv:2005.09846, doi:10.1093/mnras/staa1420
- Metcalfe, Travis S.; Egeland, Ricky (2019), "Understanding the Limitations of Gyrochronology for Old Field Stars", The Astrophysical Journal, 871 (1): 39, arXiv:1811.11905, Bibcode:2019ApJ...871...39M, doi:10.3847/1538-4357/aaf575, S2CID 119405127
- Kraus, Adam L.; Ireland, Michael J.; Huber, Daniel; Mann, Andrew W.; Dupuy, Trent J. (2016), "The Impact of Stellar Multiplicity on Planetary Systems. I. The Ruinous Influence of Close Binary Companions", The Astronomical Journal, 152 (1): 8, arXiv:1604.05744, Bibcode:2016AJ....152....8K, doi:10.3847/0004-6256/152/1/8, S2CID 119110229
- Marcy, Geoffrey W.; et al. (2014), "Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets", The Astrophysical Journal Supplement Series, 210 (2): 20, arXiv:1401.4195, Bibcode:2014ApJS..210...20M, doi:10.1088/0067-0049/210/2/20, S2CID 10760418
- Campante, T. L.; Lund, M. N.; Kuszlewicz, J. S.; Davies, G. R.; Chaplin, W. J.; Albrecht, S.; Winn, J. N.; Bedding, T. R.; Benomar, O.; Bossini, D.; Handberg, R.; Santos, A. R. G.; Van Eylen, V.; Basu, S.; Christensen-Dalsgaard, J.; Elsworth, Y. P.; Hekker, S.; Hirano, T.; Huber, D.; Karoff, C.; Kjeldsen, H.; Lundkvist, M. S.; North, T. S. H.; Silva Aguirre, V.; Stello, D.; White, T. R. (2016), "Spin–Orbit Alignment of Exoplanet Systems: Ensemble Analysis Using Asteroseismology", The Astrophysical Journal, 819 (1): 85, arXiv:1601.06052, Bibcode:2016ApJ...819...85C, doi:10.3847/0004-637X/819/1/85, S2CID 56307453
- Petrovich, Cristobal; Muñoz, Diego J.; Kratter, Kaitlin M.; Malhotra, Renu (2020), "A Disk-driven Resonance as the Origin of High Inclinations of Close-in Planets", The Astrophysical Journal Letters, 902 (1): L5, arXiv:2008.08587, Bibcode:2020ApJ...902L...5P, doi:10.3847/2041-8213/abb952, S2CID 221186597
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.