A rocky composition for an Earth-sized exoplanet

@article{Howard2013ARC,
  title={A rocky composition for an Earth-sized exoplanet},
  author={Andrew W. Howard and Roberto Sanchis-Ojeda and Geoffrey W. Marcy and John Asher Johnson and Joshua N. Winn and Howard T. Isaacson and Debra A. Fischer and Benjamin J. Fulton and Evan J. Sinukoff and Jonathan J. Fortney},
  journal={Nature},
  year={2013},
  volume={503},
  pages={381-384}
}
Planets with sizes between that of Earth (with radius ) and Neptune (about 4) are now known to be common around Sun-like stars. Most such planets have been discovered through the transit technique, by which the planet’s size can be determined from the fraction of starlight blocked by the planet as it passes in front of its star. Measuring the planet’s mass—and hence its density, which is a clue to its composition—is more difficult. Planets of size 2–4 have proved to have a wide range of… 

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References

SHOWING 1-10 OF 46 REFERENCES

An Earth-sized planet with an Earth-like density

The planet Kepler-78b was discovered and found to have a radius of only 1.16, and the mass of this planet is 1.86 Earth masses, which implies a composition of iron and rock similar to that of the Earth.

An Earth-mass planet orbiting α Centauri B

The detection of an Earth-mass planet orbiting the authors' neighbour star α Centauri B, a member of the closest stellar system to the Sun, is reported.

A PLATEAU IN THE PLANET POPULATION BELOW TWICE THE SIZE OF EARTH

We carry out an independent search of Kepler photometry for small transiting planets with sizes 0.5–8.0 times that of Earth and orbital periods between 5 and 50 days, with the goal of measuring the

TRANSITS AND OCCULTATIONS OF AN EARTH-SIZED PLANET IN AN 8.5 hr ORBIT

We report the discovery of an Earth-sized planet (1.16 ± 0.19 R⊕) in an 8.5 hr orbit around a late G-type star (KIC 8435766, Kepler-xx). The object was identified in a search for short-period planets

PLANET OCCURRENCE WITHIN 0.25 AU OF SOLAR-TYPE STARS FROM KEPLER

We report the distribution of planets as a function of planet radius, orbital period, and stellar effective temperature for orbital periods less than 50 days around solar-type (GK) stars. These

Kepler Planet-Detection Mission: Introduction and First Results

The planetary findings derived from the first six weeks of observations with the Kepler mission are summarized, which include the detection of five new exoplanets, which confirm the existence of planets with densities substantially lower than those predicted for gas giant planets.

ALL SIX PLANETS KNOWN TO ORBIT KEPLER-11 HAVE LOW DENSITIES

The Kepler-11 planetary system contains six transiting planets ranging in size from 1.8 to 4.2 times the radius of Earth. Five of these planets orbit in a tightly packed configuration with periods

Catastrophic evaporation of rocky planets

Short-period exoplanets can have dayside surface temperatures surpassing 2000 K, hot enough to vaporize rock and drive a thermal wind. Small enough planets evaporate completely. We construct a

Mass-Radius Relationships for Solid Exoplanets

We use new interior models of cold planets to investigate the mass-radius relationships of solid exoplanets, considering planets made primarily of iron, silicates, water, and carbon compounds. We

Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits

To aid in the physical interpretation of planetary radii constrained through observations of transiting planets, or eventually direct detections, we compute model radii of pure hydrogen-helium,