HAT-P-11, also designated GSC 03561-02092, is an

orange dwarf A K-type main-sequence star, also referred to as a K-type dwarf or an orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars ...

metal rich star about 123

light-years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

away in the constellation Cygnus. This star is notable for its relatively large rate of proper motion. The

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

of this star is about 9, which means it is not visible to the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal ...

but can be seen with a medium-sized amateur telescope on a clear dark night. The age of this star is about 6.5 billion years. The star has active latitudes that generate starspots. The star appears to have a very small radius, which can be explained by the anomalously high helium fraction.

Planetary system

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

, was discovered by the

HATNet Project The Hungarian Automated Telescope Network (HATNet) project is a network of six small fully automated "HAT" telescopes. The scientific goal of the project is to detect and characterize extrasolar planets using the transit method. This network is use ...

using the

transit method Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty o ...

, believed to be a little larger than the planet Neptune. That planet orbits out of alignment from the star's spin axis. The system is oblique at 100°. This star system was within the field of view of the

Kepler Mission The Kepler space telescope is a disused space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbi ...

planet-hunter

spacecraft A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...

. A trend in the radial velocity measurements taken to confirm the planet indicated a possible additional body in the system. This was confirmed in 2018 when a second planet was detected on an approximately nine year orbit. In 2020, the true mass of HAT-P-11c was measured via astrometry, along with Pi Mensae b.

References

External links

* {{Stars of Cygnus Cygnus (constellation) K-type main-sequence stars Planetary transit variables Planetary systems with two confirmed planets 3 097657 Durchmusterung objects

Planetary system

See also

References

External links