ADS

Aitken Double Star Catalogue

The Aitken Double Star Catalogue, or ADS, is a star catalogue of double stars. It was compiled by Robert Grant Aitken and published in 1932 in two volumes, under the name New general catalogue of double stars within 120° of the North Pole. It contains measurements of 17,180 double stars north of...

 16402 is a binary

Binary star

A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...

 star system

Star system

A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...

, composed of two sun-like star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

s located 450 light-years away in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Lacerta. The two stars are separated by 1500 AU

Astronomical unit

An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

s. The star system is estimated to be 3.6 billion years old. The secondary star ADS 16402 B is also designated HAT-P-1.

Planetary system

In 2006 the HATNet Project

HATNet Project

The Hungarian Automated Telescope Network 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 used also to find and follow bright variable stars...

 announced the discovery of a hot jupiter

Hot Jupiter

Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...

 type gas giant

Gas giant

A gas giant is a large planet that is not primarily composed of rock or other solid matter. There are four gas giants in the Solar System: Jupiter, Saturn, Uranus, and Neptune...

 extrasolar planet

Extrasolar planet

An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...

 in orbit around the secondary star. Following the designation scheme used by the HATNet Project, the secondary star is known as HAT-P-1, and the planet itself designated HAT-P-1b.