Editing Boötes (section)

==== Stars with planetary systems ====

[[File:Tau Bootis Ab.jpg|thumb|left|A digital rendering of Tau Boötis b]]

[[Extrasolar planet]]s have been discovered encircling ten stars in Boötes as of 2012. [[Tau Boötis]] is orbited by a large planet, discovered in 1999. The host star itself is a magnitude 4.5 star of type F7V, 15.6 [[parsec]]s from Earth. It has a mass of {{Solar mass|1.3|link=y}} and a radius of 1.331 [[solar radius|solar radii]] ({{Solar radius|link=y}}); a companion, [[GJ527B]], orbits at a distance of 240 AU. [[Tau Boötis b]], the sole planet discovered in the system, orbits at a distance of 0.046 AU every 3.31 days. Discovered through [[radial velocity]] measurements, it has a mass of 5.95 [[Jupiter mass]]es ({{Jupiter mass|link=y}}).{{sfn|Exoplanet Encyclopedia Tau Boo b}} This makes it a [[hot Jupiter]].{{sfn|Rodler|Lopez-Morales|Ribas|2012}} The host star and planet are [[tidally locked]], meaning that the planet's orbit and the star's particularly high rotation are synchronized.{{sfn|Cameron et al. 2000}}{{sfn|Walker et al.|2008}} Furthermore, a slight variability in the host star's light may be caused by magnetic interactions with the planet.{{sfn|Walker et al.|2008}} [[Carbon monoxide]] is present in the planet's atmosphere. Tau Boötis b does not [[astronomical transit|transit]] its star, rather, its orbit is inclined 46 degrees.{{sfn|Rodler|Lopez-Morales|Ribas|2012}}

Like Tau Boötis b, [[HAT-P-4b]] is also a hot Jupiter. It is noted for orbiting a particularly [[metallicity|metal-rich]] host star and being of low density.{{sfn|Kovács et al.|2007}} Discovered in 2007, HAT-P-4 b has a mass of {{Jupiter mass|0.68}} and a radius of {{Jupiter radius|1.27}}. It orbits every 3.05 days at a distance of 0.04 AU. [[HAT-P-4]], the host star, is an F-type star of magnitude 11.2, 310 parsecs from Earth. It is larger than the Sun, with a mass of {{Solar mass|1.26}} and a radius of {{Solar radius|1.59}}.{{sfn|Exoplanet Encyclopedia HAT-P-4 b}}

[[File:Hd128311.png|thumb|right|Evolution of the HD 128311 system over time]]

Boötes is also home to multiple-planet systems. [[HD 128311]] is the host star for a two-planet system, consisting of [[HD 128311 b]] and [[HD 128311 c]], discovered in 2002 and 2005, respectively.{{sfn|Exoplanet Encyclopedia HD 128311 b}}{{sfn|Exoplanet Encyclopedia HD 128311 c}} HD 128311 b is the smaller planet, with a mass of {{Jupiter mass|2.18}}; it was discovered through [[radial velocity]] observations. It orbits at almost the same distance as Earth, at 1.099 AU; however, its orbital period is significantly longer at 448.6 days.{{sfn|Exoplanet Encyclopedia HD 128311 b}}

The larger of the two, HD 128311 c, has a mass of {{Jupiter mass|3.21}} and was discovered in the same manner. It orbits every 919 days inclined at 50°, and is 1.76 AU from the host star.{{sfn|Exoplanet Encyclopedia HD 128311 c}} The host star, HD 128311, is a K0V-type star located 16.6 parsecs from Earth. It is smaller than the Sun, with a mass of {{Solar mass|0.84}} and a radius of {{Solar radius|0.73}}; it also appears below the threshold of naked-eye visibility at an apparent magnitude of 7.51.{{sfn|Exoplanet Encyclopedia HD 128311 b}}

There are several single-planet systems in Boötes. [[HD 132406]] is a Sun-like star of spectral type G0V with an apparent magnitude of 8.45, 231.5 light-years from Earth.{{sfn|Da Silva Udry et al.|2007}} It has a mass of {{Solar mass|1.09}} and a radius of {{Solar radius|1}}.{{sfn|Exoplanet Encyclopedia HD 132406}} The star is orbited by a gas giant, [[HD 132406 b]], discovered in 2007.{{sfn|Da Silva Udry et al.|2007}} HD 132406 orbits 1.98 AU from its host star with a period of 974 days and has a mass of {{Jupiter mass|5.61}}. The planet was discovered by the radial velocity method.{{sfn|Exoplanet Encyclopedia HD 132406}}

[[WASP-23]] is a star with one orbiting planet, [[WASP-23 b]]. The planet, discovered by the [[transit method]] in 2010, orbits every 2.944 days very close to its Sun, at 0.0376 AU. It is smaller than Jupiter, at {{Jupiter mass|0.884}} and {{Jupiter radius|0.962}}. Its star is a K1V-type star of apparent magnitude 12.7, far below naked-eye visibility, and smaller than the Sun at {{Solar mass|0.78}} and {{Solar radius|0.765}}.{{sfn|Exoplanet Encyclopedia WASP-23 b}}

[[HD 131496]] is also encircled by one planet, [[HD 131496 b]]. The star is of type K0 and is located 110 parsecs from Earth; it appears at a visual magnitude of 7.96. It is significantly larger than the Sun, with a mass of {{Solar mass|1.61}} and a radius of 4.6 solar radii. Its one planet, discovered in 2011 by the [[radial velocity method]], has a mass of {{Jupiter mass|2.2}}; its radius is as yet undetermined. HD 131496 b orbits at a distance of 2.09 AU with a period of 883 days.{{sfn|Exoplanet Encyclopedia HD 131496 b}}

Another single planetary system in Boötes is the [[HD 132563]] system, a [[triple star]] system. The parent star, technically [[HD 132563B]], is a star of magnitude 9.47, 96 parsecs from Earth. It is almost exactly the size of the Sun, with the same radius and a mass only 1% greater. Its planet, [[HD 132563B b]], was discovered in 2011 by the radial velocity method. {{Jupiter mass|1.49}}, it orbits 2.62 AU from its star with a period of 1544 days.{{sfn|Exoplanet Encyclopedia HD 132563B b}} Its orbit is somewhat elliptical, with an [[Orbital eccentricity|eccentricity]] of 0.22. HD 132563B b is one of very few planets found in triple star systems; it orbits the isolated member of the system, which is separated from the other components, a [[spectroscopic binary]], by 400 AU.{{sfn|Desidera et al.|2011}}

Also discovered through the radial velocity method, albeit a year earlier, is [[HD 136418 b]], a two-Jupiter-mass planet that orbits the star [[HD 136418]] at a distance of 1.32 AU with a period of 464.3 days. Its host star is a magnitude 7.88 G5-type star, 98.2 parsecs from Earth. It has a radius of {{Solar radius|3.4}} and a mass of {{Solar mass|1.33}}.{{sfn|Exoplanet Encyclopedia HD 136418 b}}

[[WASP-14 b]] is one of the most massive and dense exoplanets known,{{sfn|Joshi et al.|2009}} with a mass of {{Jupiter mass|7.341}} and a radius of {{Jupiter radius|1.281}}. Discovered via the transit method, it orbits 0.036 AU from its host star with a period of 2.24 days.{{sfn|Exoplanet Encyclopedia WASP-14 b}} WASP-14 b has a density of 4.6 grams per cubic centimeter, making it one of the densest exoplanets known.{{sfn|Joshi et al.|2009}} Its host star, [[WASP-14]], is an F5V-type star of magnitude 9.75, 160 parsecs from Earth. It has a radius of {{Solar radius|1.306}} and a mass of {{Solar mass|1.211}}.{{sfn|Exoplanet Encyclopedia WASP-14 b}} It also has a very high proportion of [[lithium]].{{sfn|Joshi et al.|2009}}