KIC 9970396

KIC 9970396
Location of KIC 9970396 (circled)
Observation data
Epoch J2000.0[1]      Equinox J2000.0[1]
Constellation Cygnus
Right ascension 19h 54m 50.35534s
Declination +46° 49′ 58.9104″
Apparent magnitude (V) 11.447[2]
Characteristics
Evolutionary stage Red-giant branch star
J−H color index 0.562[3]
J−K color index 0.661[3]
Variable type Eclipsing binary
Astrometry
Radial velocity (Rv)−2.34±8.65[4] km/s
Proper motion (μ) RA: 2.097[1] mas/yr
Dec.: −8.260[1] mas/yr
Parallax (π)0.991 ± 0.0192 mas[1]
Distance3,290 ± 60 ly
(1,010 ± 20 pc)
Orbit[2]
PrimaryKIC 9970396A
CompanionKIC 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[2]
KIC 9970396A
Mass1.178±0.015 M☉
Radius8.035±0.074 R☉
Surface gravity (log g)2.852±0.199[5] cgs
Temperature4868±143[5] K
Metallicity [Fe/H]−0.244±0.156[5] dex
Age6.13±0.19[6] Gyr
KIC 9970396B
Mass1.0030±0.0085 M☉
Radius1.1089±0.0052 R☉
Surface gravity (log g)4.3493±0.0054 cgs
Temperature6221±125 K
Other designations
Gaia DR3 2085557916175822336, KOI-7606, KIC 9970396, TIC 268059376, TYC 6466-1769-1, 2MASS J19545035+4649589[3]
Database references
SIMBADdata

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[7] 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☉.[5] Its age is estimated at 6.13±0.19 billion years,[6] about 1.5 billion years older than the Solar System (4.568 Gyr[8]).

KIC 9970396B

KIC 9970396B is a late F-type star[9] 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.[9]

Its stellar parameters, alongside those of the red giant, were precisely measured using a combination of Kepler photometry and spectroscopic observations.[2]

References

  1. ^ a b c d 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.
  2. ^ a b c d 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.
  3. ^ a b c "KOI-7606". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 October 2024.
  4. ^ 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.
  5. ^ a b c d 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.
  6. ^ a b 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.
  7. ^ "Kepler Objects of Interest". NASA Exoplanet Archive. NASA Exoplanet Science Institute. Retrieved 23 October 2024.
  8. ^ 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.
  9. ^ a b 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.