Kepler-78b
| Exoplanet | List of exoplanets | |
|---|---|---|
 |
||
| Parent star | ||
| Star | Kepler-78 | |
| Constellation | Cygnus | |
| Right ascension | (α) | 19h 34m 58s |
| Declination | (δ) | +44° 26′ 54″ |
| Apparent magnitude | (mV) | 12 |
| Distance | 400 ly ( pc) |
|
| Radius | (r) | 0.73±0.15 R☉ |
| Temperature | (T) | 5143 (± 70) K |
| Metallicity | [Fe/H] | -0.08 (± 0.13) |
| Physical characteristics | ||
| Mass | (m) | 1.69-1.85 M⊕ |
| Radius | (r) | 1.12 R⊕ |
| Bond Albedo | (Ab) | 0.2-0.6 |
| Density | (ρ) | 5.3-5.6 g cm−3 |
| Orbital elements | ||
| Semi-major axis | (a) | 0.01 AU |
| Orbital period | (P) | 0.355007 d |
| Inclination | (i) | 81 +6 −9° |
| Discovery information | ||
| Discovery date | November 5, 2013 | |
| Discoverer(s) | ||
| Discovery method | Transit and reflection/emission modulations (Kepler Mission) | |
| Other detection methods | Radial velocity | |
| Discovery status | Confirmed | |
| Other designations | ||
|
Kepler-78b, KIC 8435766 b
|
||
Kepler-78b (formerly known as KIC 8435766 b) is an exoplanet orbiting around the star Kepler-78. At the time of its discovery, it was the known exoplanet most similar to Earth in terms of mass, radius and mean density.
The planet was discovered in 2013 by analyzing data from the Kepler space telescope. The planet was found not only transiting the star, but its occultation and reflected light from the parent star due to orbital phases were also detected. It did not have Kepler object of interest designation at first as the automatic data analysis missed this planet due to its short period.
Kepler-78b is 69% more massive than Earth and 20% larger. Two independent teams were involved in pioneering work to estimate the mass of the planet. The estimates were made possible because Kepler-78b's gravity causes a "wobble" in the orbit of the host star. While the method has been used to characterize gas giants, ordinarily it is hard to estimate the mass of Earth-sized exoplanets because their gravity is too weak to produce a visible influence on their stars. In this case, the planet's orbit is so close to its star that its gravitational influence has a detectable effect.
One team, led by Francesco Pepe, used the High Accuracy Radial Velocity Planet Searcher-North (HARPS-N) spectrograph at the Telescopio Nazionale Galileo in the Canary Islands to estimate that the planet has a mass 1.86 times that of the Earth and a radius 1.16 times. The other, led by Andrew Howard of the University of Hawaii at Manoa, used data from the High Resolution Eschelle Spectrometer on the Keck 1 Telescope at the W.M. Keck Observatory in Hawaii to estimate the mass as 1.69 times that of the Earth and the radius as 1.2 times. Both estimates put the planet's density at about 5.5 grams per cubic centimetre, equivalent to that of the Earth and possibly indicative of a rock-iron composition like Earth's. The iron core could build up to 40% of the planet mass.
...
Wikipedia