exoplanet
An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...
light years
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astro ...
away, in the constellation
Lyra
, from ; pronounced: ) is a small constellation. It is one of the 48 listed by the 2nd century astronomer Ptolemy, and is one of the modern 88 constellations recognized by the International Astronomical Union. Lyra was often represented on star ...
. With an orbital period of 39.8 days, it is the largest of the three known planets orbiting its parent star
Kepler-37
Kepler-37, also known as UGA-1785, is a G-type main-sequence star located in the constellation Lyra from Earth. It is host to exoplanets Kepler-37b, Kepler-37c, Kepler-37d and possibly Kepler-37e, all of which orbit very close to it. ...
.
A 2021 study detected Kepler-37d via
radial velocity
The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...
, finding a mass of about , but a 2023 study instead found an upper limit on its mass of only . In either case, it is not a rocky planet, but a low-density planet rich in
volatiles
Volatility or volatile may refer to:
Chemistry
* Volatility (chemistry), a measuring tendency of a substance or liquid to vaporize easily
** Volatile organic compounds, organic or carbon compounds that can evaporate at normal temperature and pre ...
.
In 2015, a grant was approved to further expand the
Sagan Planet Walk
The Sciencenter's Sagan Planet Walk is a walkable scale model of the Solar System, located in Ithaca, New York. The model scales the entire Solar System—both planet size and distances between them—down to one five billionth of its actual si ...
by installing a Kepler-37d station on the Moon away.
star
A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
similar to the
Sun
The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
, named
Kepler-37
Kepler-37, also known as UGA-1785, is a G-type main-sequence star located in the constellation Lyra from Earth. It is host to exoplanets Kepler-37b, Kepler-37c, Kepler-37d and possibly Kepler-37e, all of which orbit very close to it. ...
, orbited by a total of four planets. The star has a mass of 0.80 and a radius of 0.79 . It has a temperature of 5417 K and is 5.66 billion years old. In comparison, the Sun is 4.6 billion years old, and has a temperature of 5778 K.
The star's
apparent magnitude
Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...
, or how bright it appears from Earth's perspective, is 9.71. Therefore, it is too dim to be seen with the naked eye.