Astronomy:KIC 9970396
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 19h 54m 50.35534s[2] |
| Declination | +46° 49′ 58.9104″[2] |
| Apparent magnitude (V) | 11.447[3] |
| Characteristics | |
| Evolutionary stage | Red-giant branch + main sequence[3] |
| Spectral type | G6V[4] or G9III-IV[5] |
| J−H color index | 0.562[6] |
| J−K color index | 0.661[6] |
| Variable type | Eclipsing binary[3] |
| Astrometry | |
| Radial velocity (Rv) | −13.05±4.32[2] km/s |
| Proper motion (μ) | RA: 2.097[2] mas/yr Dec.: −8.260[2] mas/yr |
| Parallax (π) | 0.991 ± 0.0192[2] mas |
| Distance | 3,290 ± 60 ly (1,010 ± 20 pc) |
| Orbit[3] | |
| Primary | KIC 9970396A |
| Companion | KIC 9970396B |
| Period (P) | 235.29861±0.00024 d |
| Semi-major axis (a) | 0.9669±0.0034 astronomical unit|AU |
| Eccentricity (e) | 0.1942±0.0053 |
| Inclination (i) | 89.437±0.046° |
| Details[3] | |
| KIC 9970396A | |
| Mass | 1.178±0.015 M☉ |
| Radius | 8.035±0.074 R☉ |
| Surface gravity (log g) | 2.852±0.199[7] cgs |
| Temperature | 4868±143[7] K |
| Metallicity [Fe/H] | −0.244±0.156[7] dex |
| Age | 6.13±0.19[8] Gyr |
| KIC 9970396B | |
| Mass | 1.0030±0.0085 M☉ |
| Radius | 1.1089±0.0052 R☉ |
| Surface gravity (log g) | 4.3493±0.0054 cgs |
| Temperature | 6221±125 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
KIC 9970396 is an eclipsing binary system located in the northern constellation of Cygnus about 3,290 light-years (1,010 parsecs) distant. The system consists of a red-giant branch star and an F-type main-sequence star. The two stars orbit each other every 235 days (0.64 years) at a mean distance of 207.92±0.73 R☉ (0.9669±0.0034 AU), almost the same as Earth's distance from the Sun.
The system was given the Kepler Object of Interest designation KOI-7606 as a planetary candidate, but has been marked a false positive[9] since the dips in the light curve are caused by an eclipsing stellar companion rather than a transiting exoplanet.
Stellar components
KIC 9970396A
KIC 9970396A is a pulsating red giant currently in the red-giant branch, past the first dredge-up event and approaching the red giant bump. The star displays solar-like oscillations caused by turbulent convection near the surface. Since the star has used up all of its hydrogen within its core, the core now consists mostly of helium, with a mass of 0.229 M☉, that is 19% of the star's entire mass, and a radius of 0.03055 R☉.[7] Its age is estimated at 6.13±0.19 billion years,[8] about 1.5 billion years older than the Solar System (4.568 Gyr).[10]
KIC 9970396B
KIC 9970396B is a late F-type star[11] almost identical in mass to the Sun but slightly larger and hotter. Its mass is slightly smaller than the red giant primary, thus a possible scenario for the system is that the two stars formed together and the more massive primary star evolved past the main sequence first.[11]
Its stellar parameters, alongside those of the red giant, were precisely measured using a combination of Kepler photometry and spectroscopic observations.[3]
References
- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R Constellation record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Brogaard, K et al. (2018-02-01). "Establishing the accuracy of asteroseismic mass and radius estimates of giant stars – I. Three eclipsing systems at [Fe/H] ∼ −0.3 and the need for a large high-precision sample". Monthly Notices of the Royal Astronomical Society (Oxford University Press (OUP)) 476 (3): 3729–3743. doi:10.1093/mnras/sty268. ISSN 0035-8711.
- ↑ Frasca, A.; Molenda-Żakowicz, J.; De Cat, P.; Catanzaro, G.; Fu, J. N.; Ren, A. B.; Luo, A. L.; Shi, J. R. et al. (2016). "Activity indicators and stellar parameters of the Kepler targets. An application of the ROTFIT pipeline to LAMOST-Kepler stellar spectra". Astronomy and Astrophysics 594. doi:10.1051/0004-6361/201628337. Bibcode: 2016A&A...594A..39F.
- ↑ Gray, R. O.; Corbally, C. J.; De Cat, P.; Fu, J. N.; Ren, A. B.; Shi, J. R.; Luo, A. L.; Zhang, H. T. et al. (2016). "LAMOST Observations in the Kepler Field: Spectral Classification with the MKCLASS Code". The Astronomical Journal 151 (1): 13. doi:10.3847/0004-6256/151/1/13. Bibcode: 2016AJ....151...13G.
- ↑ 6.0 6.1 6.2 "KOI-7606". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=KOI-7606.
- ↑ 7.0 7.1 7.2 7.3 Zhang, Xinyi et al. (2020-04-02). "Determining the size of the helium core of KIC 9970396 using asteroseismology: a red giant approaching the red giant bump". Monthly Notices of the Royal Astronomical Society (Oxford University Press (OUP)) 494 (1): 511–528. doi:10.1093/mnras/staa667. ISSN 0035-8711.
- ↑ 8.0 8.1 Zhang, Xinyi et al. (2022-05-01). "Determining the Age for the Red Giants KIC 9145955 and KIC 9970396 by Gravity-dominated Mixed Modes". The Astrophysical Journal (American Astronomical Society) 931 (1): 64. doi:10.3847/1538-4357/ac695b. ISSN 0004-637X. Bibcode: 2022ApJ...931...64Z.
- ↑ "Kepler Objects of Interest". NASA Exoplanet Archive. NASA Exoplanet Science Institute. https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=cumulative.
- ↑ Bouvier, A.; Wadhwa, M. (2010). "The age of the Solar System redefined by the oldest Pb–Pb age of a meteoritic inclusion". Nature Geoscience 3 (9): 637–641. doi:10.1038/NGEO941. Bibcode: 2010NatGe...3..637B.
- ↑ 11.0 11.1 Gaulme, P.; McKeever, J.; Rawls, M. L.; Jackiewicz, J.; Mosser, B.; Guzik, J. A. (2013). "Red Giants in Eclipsing Binary and Multiple-star Systems: Modeling and Asteroseismic Analysis of 70 Candidates from Kepler Data". The Astrophysical Journal 767 (1): 82. doi:10.1088/0004-637X/767/1/82. Bibcode: 2013ApJ...767...82G.
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