Kepler-10

Kepler-10

An artist's depiction of the Kepler-10 system. Kepler-10c is in the foreground.
Observation data Epoch J2000      Equinox J2000
Constellation	Draco
Right ascension	19h 02m 43.06139s[1]
Declination	+50° 14′ 28.7016″[1]
Apparent magnitude (V)	11.157[2]
Characteristics
Spectral type	G2V[3]
Astrometry
Radial velocity (Rv)	−98.44±0.24[1] km/s
Proper motion (μ)	RA: −18.483 mas/yr[1] Dec.: 41.382 mas/yr[1]
Parallax (π)	5.3698 ± 0.0103 mas[1]
Distance	607 ± 1 ly (186.2 ± 0.4 pc)
Details
Mass	0.910±0.021[2] M☉
Radius	1.065±0.009[2] R☉
Temperature	5708±28[2] K
Metallicity [Fe/H]	−0.15±0.04[4] dex
Age	10.6+1.5 −1.3[2] Gyr
Other designations
KOI-72, KIC 11904151, GSC 03549-00354, 2MASS J19024305+5014286[3]
Database references
SIMBAD	data
KIC	data

Kepler-10, formerly known as KOI-72, is a Sun-like star in the constellation of Draco that lies 607 light-years (186 parsecs) from Earth.^[5][6] Kepler-10 was targeted by NASA's Kepler spacecraft, as it was seen as the first star identified by the Kepler mission that could be a possible host to a small, transiting exoplanet.^[7] The star is slightly less massive, slightly larger, and slightly cooler than the Sun; at an estimated 11.9 billion years in age, Kepler-10 is 2.3 times the age of the Sun.^[2]

Kepler-10 is host to a planetary system made up of at least three planets. Kepler-10b, the first undeniably rocky planet,^[7] was discovered in its orbit after eight months of observation and announced on January 10, 2011. The planet orbits its star closely, completing an orbit every 0.8 days,^[8] and has a density similar to that of iron.^[7] The second planet, Kepler-10c, was confirmed on May 23, 2011, based on follow-up observations by the Spitzer Space Telescope. The data shows it has an orbital period of 42.3 days and has a radius more than double that of Earth, but it was initially thought to have a higher density, making it the largest and most massive rocky planet discovered as of June 2014.^[2][9][10] However, refined mass measurements have shown it to be a more typical volatile-rich planet.^[11] A third planet, Kepler-10d, was discovered in 2023 by radial velocity observations.^[4]

Nomenclature and history

Kepler-10 was named because it was the tenth planetary system observed by the Kepler spacecraft, a NASA satellite designed to search for Earth-like planets that transit, or cross in front of, their host stars with respect to Earth. The transit slightly dims the host star; this periodic dimming effect is then noted by Kepler.^[12] After eight months of observation ranging from May 2009 to January 2010, the Kepler team established Kepler-10b as the first rocky exoplanet discovered by the Kepler satellite. Kepler-10 was the first Kepler-targeted star suspected of having a small planet in orbit. Because of that, verifying Kepler's discovery was prioritized by telescopes at the W.M. Keck Observatory in Hawaii. The discovery was successfully verified.^[7] Although there had been many potentially rocky exoplanets discovered in the past, Kepler-10b was the first definitively rocky planet to have been discovered.^[13]

The discovery of Kepler-10b was announced to the public at a winter meeting of the American Astronomical Society on January 10, 2011 in Seattle.^[13] On May 23, 2011, the existence of Kepler-10c was confirmed at the 218th AAS meeting in Boston.^[14]

Characteristics

Kepler-10 is a G-type star, like the Sun. With a mass of 0.895 (± 0.06) M_sun and a radius of 1.056 (± 0.021) R_sun, the star is approximately 10% less massive than and 5% wider than the Sun. The metallicity of Kepler-10, as measured in [Fe/H] (the amount of iron in the star), is -0.15 (± 0.04); this means that Kepler-10 is about 70% as metal-rich as the Sun. Metallicity tends to play a large role in the formation of planets, determining if they form, and what kind of planet they will form.^[15] In addition, Kepler-10 is estimated to be 11.9 billion years old and to have an effective temperature of 5627 (± 44) K;^[5] To compare, the Sun is younger and hotter, with an age of 4.6 billion years^[16] and an effective temperature of 5778 K.^[17]

Kepler-10 is located at a distance of 186 parsecs from the Earth, which equates to approximately 607 light years. Also, Kepler-10's apparent magnitude, or brightness as seen from Earth, is 10.96; it therefore cannot be seen with the naked eye.^[5]

Planetary system

Per the usual exoplanet nomenclature, the first planet discovered to be orbiting Kepler-10 is called Kepler-10b. Announced in 2011, it was the first definitely rocky planet identified outside the Solar system. The planet has a mass that is 3.33±0.49 times that of Earth's and a radius that is 1.47^+0.03
_−0.02 times that of Earth.^[2] The planet orbits Kepler-10 at a distance of 0.01684 AU every 0.8375 days; this can be compared to the orbit and orbital period of planet Mercury, which circles the Sun at a distance of 0.3871 AU every 87.97 days.^[18] Because the planet orbits so closely to its star, its eccentricity is virtually zero. It, thus, has an extremely circular orbit.^[8]

Kepler-10c^[9] was also discovered by NASA's Kepler Mission,^[19] the second exoplanet found to orbit Kepler-10. Radial-velocity measurements of the body initially suggested that it has a mass of 17.2±1.9 Earth masses and a radius of 2.35 Earth radii, which would have made it the largest known rocky planet as of 2014^[update]. Kepler-10c would orbit Kepler-10 at a distance of 0.24 AU every 45.29 days.^[2] However, in July 2017, more careful analysis of HARPS-N and HIRES data showed that Kepler-10c was much less massive than originally thought, instead around 7.37+1.32
−1.19 M_E with a mean density of 3.14 g/cm³. Instead of a primarily rocky composition, the more accurately determined mass of Kepler-10c suggests a world made almost entirely of volatiles, mainly water.^[11]

A candidate third planet with an orbital period of about 102 days, given the provisional designation KOI-72.X, was identified in 2016 based on transit-timing variations.^[20][11] In 2023, the presence of a third planet, Kepler-10d, was confirmed by radial velocity observations. It has an orbital period of 151 days and a minimum mass about 13 times that of Earth.^[4]

See also

• Kepler Mission
• List of exoplanets

References

This page was last edited on 29 February 2024, at 22:02