Location of KIC 9970396 (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19 54 50.35534 |
| Declination | +46° 49′ 58.9104″ |
| Apparent magnitude (V) | 11.447 |
| Characteristics | |
| Evolutionary stage | Red-giant branch star |
| J−H color index | 0.562 |
| J−K color index | 0.661 |
| Variable type | Eclipsing binary |
| Astrometry | |
| Radial velocity (Rv) | −2.34±8.65 km/s |
| Proper motion (μ) | RA: 2.097 mas/yr Dec.: −8.260 mas/yr |
| Parallax (π) | 0.991 ± 0.0192 mas |
| Distance | 3,290 ± 60 ly (1,010 ± 20 pc) |
| Orbit | |
| Primary | KIC 9970396A |
| Companion | KIC 9970396B |
| Period (P) | 235.29861±0.00024 d |
| Semi-major axis (a) | 0.9669±0.0034 AU |
| Eccentricity (e) | 0.1942±0.0053 |
| Inclination (i) | 89.437±0.046° |
| Details | |
| KIC 9970396A | |
| Mass | 1.178±0.015 M☉ |
| Radius | 8.035±0.074 R☉ |
| Surface gravity (log g) | 2.852±0.199 cgs |
| Temperature | 4868±143 K |
| Metallicity | −0.244±0.156 dex |
| Age | 6.13±0.19 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 | |
| Gaia DR3 2085557916175822336, KOI-7606, KIC 9970396, TIC 268059376, TYC 6466-1769-1, 2MASS J19545035+4649589 | |
| 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 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☉. Its age is estimated at 6.13±0.19 billion years, about 1.5 billion years older than the Solar System (4.568 Gyr).
KIC 9970396B
KIC 9970396B is a late F-type star 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.
Its stellar parameters, alongside those of the red giant, were precisely measured using a combination of Kepler photometry and spectroscopic observations.
References
- ^ 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.
- ^ Brogaard, K; et al. (1 February 2018). "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. 476 (3). Oxford University Press (OUP): 3729–3743. arXiv:1801.08167. doi:10.1093/mnras/sty268. ISSN 0035-8711.
- ^ "KOI-7606". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 October 2024.
- 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.
- ^ Zhang, Xinyi; et al. (2 April 2020). "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. 494 (1). Oxford University Press (OUP): 511–528. doi:10.1093/mnras/staa667. ISSN 0035-8711.
- ^ Zhang, Xinyi; et al. (1 May 2022). "Determining the Age for the Red Giants KIC 9145955 and KIC 9970396 by Gravity-dominated Mixed Modes". The Astrophysical Journal. 931 (1). American Astronomical Society: 64. doi:10.3847/1538-4357/ac695b. ISSN 0004-637X.
- "Kepler Objects of Interest". NASA Exoplanet Archive. NASA Exoplanet Science Institute. Retrieved 23 October 2024.
- 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. Bibcode:2010NatGe...3..637B. doi:10.1038/NGEO941. S2CID 56092512.
- ^ Gaulme, P.; et al. (26 March 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). American Astronomical Society: 82. arXiv:1303.1197. doi:10.1088/0004-637x/767/1/82. ISSN 0004-637X.