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] |
Distance | 3,290 ± 60 ly (1,010 ± 20 pc) |
Orbit [2] | |
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 [2] | |
KIC 9970396A | |
Mass | 1.178±0.015 M☉ |
Radius | 8.035±0.074 R☉ |
Surface gravity (log g) | 2.852±0.199 [5] cgs |
Temperature | 4868±143 [5] K |
Metallicity [Fe/H] | −0.244±0.156 [5] dex |
Age | 6.13±0.19 [6] 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 [7] since the dips in the light curve are caused by an eclipsing stellar companion rather than a transiting exoplanet.
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 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]
HD 17156, named Nushagak by the IAU, is a yellow subgiant star approximately 255 light-years away in the constellation of Cassiopeia. The apparent magnitude is 8.17, which means it is not visible to the naked eye but can be seen with good binoculars. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.
HAT-P-7 is a F-type main sequence star located about 1088 light-years away in the constellation Cygnus. The apparent magnitude of this star is 10.5, which means it is not visible to the naked eye but can be seen with a small telescope on a clear dark night.
HAT-P-8 is a magnitude 10 star located 700 light-years away in Pegasus. It is a F-type star about 28% more massive than the Sun. Two red dwarf companions have been detected around HAT-P-8. The first has a spectral type of M5V and has a mass of 0.22 M☉. The second is even less massive, at 0.18 M☉, and its spectral type is M6V.
The Kepler Input Catalog is a publicly searchable database of roughly 13.2 million targets used for the Kepler Spectral Classification Program (SCP) and the Kepler space telescope.
HAT-P-17 is a K-type main-sequence star about 92.4 parsecs (301 ly) away. It has a mass of about 0.857 ± 0.039 M☉. It is the host of two planets, HAT-P-17b and HAT-P-17c, both discovered in 2010. A search for a binary companion star using adaptive optics at the MMT Observatory was negative. A candidate companion was detected by a spectroscopic search of high-resolution K band infrared spectra taken at the Keck observatory.
Kepler-70, also known as KIC 5807616 and KOI-55, is a star about 3,600 light-years away in the constellation Cygnus, with an apparent visual magnitude of 14.87. This is too faint to be seen with the naked eye; viewing it requires a telescope with an aperture of 40 cm (20 in) or more. A subdwarf B star, Kepler-70 passed through the red giant stage some 18.4 million years ago. In its present-day state, it is fusing helium in its core. Once it runs out of helium it will contract to form a white dwarf. It has a relatively small radius of about 0.2 times the Sun's radius; white dwarfs are generally much smaller. The star may be host to a planetary system with two planets, although later research indicates that this is not in fact the case.
Kepler-35 is a binary star system in the constellation of Cygnus. These stars, called Kepler-35A and Kepler-35B have masses of 89% and 81% solar masses respectively, and both are assumed to be of spectral class G. They are separated by 0.176 AU, and complete an eccentric orbit around a common center of mass every 20.73 days.
Kepler-65 is a subgiant star slightly more massive than the Sun and has at least four planets.
Kepler-56 is a red giant in constellation Cygnus roughly 3,030 light-years (930 pc) away with slightly more mass than the Sun.
Kepler-90g is a super-puff exoplanet orbiting the early G-type main sequence star Kepler-90, one of eight planets around this star discovered using NASA's Kepler space telescope. It is located about 2,840 light-years (870 pc) from Earth, in the constellation Draco. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. It orbits its parent star about every 210.5 days at a distance of 0.71 astronomical units.
Kepler-444 is a triple star system, estimated to be 11.2 billion years old, approximately 119 light-years (36 pc) away from Earth in the constellation Lyra. On 27 January 2015, the Kepler spacecraft is reported to have confirmed the detection of five sub-Earth-sized rocky exoplanets orbiting the main star. The star is a K-type main sequence star. All of the planets are far too close to their star to harbour life forms.
KOI-256 is a double star located in the constellation Cygnus approximately 575 light-years (176 pc) from Earth. While observations by the Kepler spacecraft suggested the system contained a gas giant exoplanet orbiting a red dwarf, later studies determined that KOI-256 was a binary system composed of the red dwarf orbiting a white dwarf.
Kepler-1520b, is a confirmed exoplanet orbiting the K-type main sequence star Kepler-1520. It is located about 2,020 light-years away from Earth in the constellation of Cygnus. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. The planet was previously proposed in 2012 when reports of its host star recorded drops in its luminosity varying from 0.2% to 1.3%, which indicated a possible planetary companion rapidly disintegrating. In 2015, the planetary nature of the cause of the dips was finally verified. It is expected to disintegrate in about 40–400 million years.
Kepler-13 or KOI-13 is a stellar triple star system consisting of Kepler-13A, around which an orbiting hot Jupiter exoplanet was discovered with the Kepler space telescope in 2011, and Kepler-13B a common proper motion companion star which has an additional star orbiting it.
HD 179070, also known as Kepler-21, is a star with a closely orbiting exoplanet in the northern constellation of Lyra. At an apparent visual magnitude of 8.25 this was the brightest star observed by the Kepler spacecraft to host a validated planet until the discovery of an exoplanet orbiting HD 212657 in 2018. This system is located at a distance of 354 light-years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −18.2 km/s.
Kepler-410 is a binary star system. Its primary star, also known as Kepler-410A, is a F-type subgiant star, orbited by the orange dwarf star Kepler-410B on a wide orbit. The companion star was discovered in 2012.
KIC 11145123, is a white hued star located in the northern constellation Cygnus, the swan. It has an apparent magnitude of 13.12, making it readily visible in large telescopes, but not to the naked eye. The object is located relatively far at a distance of approximately 3,910 light years, but is rapidly approaching the Solar System with a radial velocity of −136 km/s.
KOI-2700b is a confirmed exoplanet that orbits the K-type main-sequence star KIC 8639908, located about 1,608 light-years distant. It orbits the star very rapidly, with an orbital period of 0.91 days, at a distance of just 0.0150 AU (2,240,000 km). This, along with its small mass, is causing it to evaporate and lose material, which leaves a comet-like tail of dust stretching from the planet.
HIP 94292, commonly referred to by its KIC designation KIC 9145955, is a red-giant branch star located in the northern constellation of Lyra.
HD 190655 (KOI-3886) is a hierarchical triple star system located about 1,500 light-years away in the northern constellation of Cygnus. It has a combined apparent magnitude of 10.114, making it readily visible using a small telescope with an aperture of 35 mm or larger, but too faint to observe via the naked eye or binoculars.