HAT-P-13
Encyclopedia
HAT-P-13, also known as GSC 03416-00543, is a G-type main sequence star
approximately 697 light-year
s away in the constellation
Ursa Major
. In 2009 it was discovered that this star is orbited by two massive planets
, the innermost of which transits the star. This was the first known example of an extrasolar transiting planet with an additional planet in the same system.
s orbiting it. The inner planet was discovered by the "transit method" and the outer planet was found through the radial velocity
method. It is not known whether HAT-P-13c transits. HAT-P-13 was the first star to have a transiting planet and an additional planet on a known orbit. HAT-P-7
and other planets are known to have additional companions, but there is not enough data to characterize the system. OGLE-TR-111
has one confirmed transiting planet, and one unconfirmed transiting planet.
The innermost planet, HAT-P-13b
, has a mass around that of Jupiter
and orbits its sun roughly every three days. This classifies the planet as a hot Jupiter
, with temperatures exceeding 1000 kelvin
s. The second companion, HAT-P-13c
, has a mass over 15 Jupiters. Because of its mass, this companion could either be a massive planet or a low mass brown dwarf
. Either way, HAT-P-13 c orbits its sun every 428.5 days in a highly eccentric orbit. Radial velocity measurements also suggest the existence of a third more distant companion in the system. This may be an additional planet, or it may be a brown dwarf or even a small 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...
approximately 697 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s 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....
Ursa Major
Ursa Major
Ursa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...
. In 2009 it was discovered that this star is orbited by two massive planets
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...
, the innermost of which transits the star. This was the first known example of an extrasolar transiting planet with an additional planet in the same system.
Planetary system
As of 2009, HAT-P-13 has been confirmed to have two extrasolar planetExtrasolar 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...
s orbiting it. The inner planet was discovered by the "transit method" and the outer planet was found through the radial velocity
Radial velocity
Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...
method. It is not known whether HAT-P-13c transits. HAT-P-13 was the first star to have a transiting planet and an additional planet on a known orbit. HAT-P-7
HAT-P-7
HAT-P-7 is a yellow white dwarf star located about 1044 light-years away in the constellation Cygnus. The apparent magnitude of this star is 10.5, which means it is not visible to the naked eye but can be seen with a small telescope on a clear dark night.-Planetary system:This star has one known...
and other planets are known to have additional companions, but there is not enough data to characterize the system. OGLE-TR-111
OGLE-TR-111
OGLE-TR-111 is a yellow dwarf star approximately 5,000 light-years away in the constellation of Carina . Having an apparent magnitude of about 17 this distant and dim star has not yet been cataloged.- Planetary system :...
has one confirmed transiting planet, and one unconfirmed transiting planet.
The innermost planet, HAT-P-13b
HAT-P-13b
HAT-P-13b is an extrasolar planet approximately 697 light-years away in the constellation Ursa Major. The planet was discovered when it transited across its sun, HAT-P-13. This planet is a hot Jupiter with 0.851 times the mass of Jupiter and 1.28 radius. The planet has a lower mass, but its overall...
, has a mass around that of Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
and orbits its sun roughly every three days. This classifies the planet as a hot Jupiter
Hot Jupiter
Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...
, with temperatures exceeding 1000 kelvin
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
s. The second companion, HAT-P-13c
HAT-P-13c
HAT-P-13c is a substellar object orbiting the star HAT-P-13 located 698 light years away from Earth in the constellation of Ursa Major. With a mass at least 15.2 times that of Jupiter, it may be a massive planet or a small brown dwarf...
, has a mass over 15 Jupiters. Because of its mass, this companion could either be a massive planet or a low mass brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
. Either way, HAT-P-13 c orbits its sun every 428.5 days in a highly eccentric orbit. Radial velocity measurements also suggest the existence of a third more distant companion in the system. This may be an additional planet, or it may be a brown dwarf or even a small star.