WASP-13
Encyclopedia
WASP-13 is a star in the Lynx
constellation. The star is similar, in terms of metallicity
and mass, to the Sun
, although it is hotter and most likely older. The star was first observed in 1997, according to the SIMBAD
database, and was targeted by SuperWASP
after the star was observed by one of the SuperWASP telescopes beginning in 2006. Follow-up observations on the star led to the discovery of planet WASP-13b
in 2008; the discovery paper was published in 2009.
, WASP-13 was first observed in 1997, when it was catalogued by astronomers measuring the proper motion
of stars in regions of the sky where galaxies are detected. Between November 27, 2006, and April 1, 2007, the SuperWASP
-North telescope in the Canary Islands observed WASP-13; analysis of the data suggested that a planet could be in the orbit of the star.
Follow-up observations were conducted by a team of British, Spanish, French, Swiss and American astronomers using the photometer
on the James Gregory Telescope
in Scotland; using visual comparisons to the nearby bright star HD 80408, the star's light curve was better defined. In combination with measurements of WASP-13's spectrum
measured using the SOPHIE échelle spectrograph
at the Haute-Provence Observatory
in France, the star's radial velocity
was also discovered. The Fibre-Fed Echelle Spectrograph on the Nordic Optical Telescope
gathered additional measurements of WASP-13's spectrum, allowing astronomers to determine WASP-13's characteristics. Use of SOPHIE's data led to the discovery of the planet WASP-13b
in 2008; the planet was reported in 2009.
Based on SIMBAD's archive, WASP-13 was included in ten more papers between its discovery and 2010.
s (509 light years) in the Lynx
constellation. With an apparent magnitude
of 10.42, the star cannot be seen with the unaided eye from the perspective of someone on Earth. The star's effective temperature
, at 5826 K, is hotter than that of the Sun. However, its metallicity
is similar; this can be seen in how the concentration of iron, or [Fe/H], is approximately 0. WASP-13's surface gravity
is measured at 4.04 km/s2, while the rate at which it rotates
is at most 4.9 km/s.
WASP-13 has a mass that is 1.03 times
the mass of the Sun and a radius that is 1.34 times the Sun's radius. Measurements of its lithium
content suggest that the star has used up all of its helium and is now fusing lithium in the shell around its core. With this, its estimated age is 8.5 billion years, over twice the age of the Sun, but this age may vary to any point between 4.4 and 14 billion years in age because of the high uncertainty surrounding this aspect of the star's age.
, or approximately 5.27% of the mean distance between the Earth and Sun. The planet completes an orbit every 4.35298 days, or approximately 4 days and 8.5 hours. WASP-13b's estimated mass is 0.46 times the mass
of Jupiter
, while its radius is about 1.21 times that of the planet.
Lynx (constellation)
Lynx is a constellation in the northern sky, introduced in the 17th century by Johannes Hevelius. It is named after the lynx, a genus of cat. It is a very faint constellation; its brightest stars form a zigzag line.-History:...
constellation. The star is similar, in terms of metallicity
Metallicity
In astronomy and physical cosmology, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium...
and mass, to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
, although it is hotter and most likely older. The star was first observed in 1997, according to the SIMBAD
SIMBAD
SIMBAD is an astronomical database of objects beyond the Solar System...
database, and was targeted by SuperWASP
SuperWASP
SuperWASP is an international academic organisation performing an ultra-wide angle search for transiting extrasolar planets with the aim of covering the entire sky down to ~15th magnitude.-Equipment:...
after the star was observed by one of the SuperWASP telescopes beginning in 2006. Follow-up observations on the star led to the discovery of planet WASP-13b
WASP-13b
WASP-13b is an extrasolar planet that was discovered in 2008 in the orbit of the sunlike star WASP-13. The planet has a mass of nearly half that of Jupiter, but a radius five-fourths the size of Jupiter...
in 2008; the discovery paper was published in 2009.
Observational history
According to SIMBADSIMBAD
SIMBAD is an astronomical database of objects beyond the Solar System...
, WASP-13 was first observed in 1997, when it was catalogued by astronomers measuring the proper motion
Proper motion
The proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...
of stars in regions of the sky where galaxies are detected. Between November 27, 2006, and April 1, 2007, the SuperWASP
SuperWASP
SuperWASP is an international academic organisation performing an ultra-wide angle search for transiting extrasolar planets with the aim of covering the entire sky down to ~15th magnitude.-Equipment:...
-North telescope in the Canary Islands observed WASP-13; analysis of the data suggested that a planet could be in the orbit of the star.
Follow-up observations were conducted by a team of British, Spanish, French, Swiss and American astronomers using the photometer
Photometer
In its widest sense, a photometer is an instrument for measuring light intensity or optical properties of solutions or surfaces. Photometers are used to measure:*Illuminance*Irradiance*Light absorption*Scattering of light*Reflection of light*Fluorescence...
on the James Gregory Telescope
James Gregory Telescope
The James Gregory Telescope was constructed in 1962 by the University of St Andrews. It is of a Schmidt-Cassegrain design and is fitted with a CCD camera...
in Scotland; using visual comparisons to the nearby bright star HD 80408, the star's light curve was better defined. In combination with measurements of WASP-13's spectrum
Spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
measured using the SOPHIE échelle spectrograph
SOPHIE échelle spectrograph
The SOPHIE échelle spectrograph is a high-resolution echelle spectrograph installed on the 1.93m reflector telescope at the Haute-Provence Observatory located in south-eastern France...
at the Haute-Provence Observatory
Haute-Provence Observatory
The Observatoire de Haute-Provence was established in 1937 as a national facility for French astronomers. Astronomical observations began in 1943 using the 1.20 m telescope, and the first research papers based on observations made at the observatory were published in 1944...
in France, the star's 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...
was also discovered. The Fibre-Fed Echelle Spectrograph on the Nordic Optical Telescope
Nordic Optical Telescope
The Nordic Optical Telescope is an astronomical telescope located at Roque de los Muchachos Observatory, La Palma in the Canary Islands. First light came in 1988, with regular observing beginning in 1989. It is funded by Denmark, Sweden, Iceland, Norway and Finland...
gathered additional measurements of WASP-13's spectrum, allowing astronomers to determine WASP-13's characteristics. Use of SOPHIE's data led to the discovery of the planet WASP-13b
WASP-13b
WASP-13b is an extrasolar planet that was discovered in 2008 in the orbit of the sunlike star WASP-13. The planet has a mass of nearly half that of Jupiter, but a radius five-fourths the size of Jupiter...
in 2008; the planet was reported in 2009.
Based on SIMBAD's archive, WASP-13 was included in ten more papers between its discovery and 2010.
Characteristics
WASP-13 is a sunlike, G-type star that is situated approximately 156 parsecParsec
The parsec is a unit of length used in astronomy. It is about 3.26 light-years, or just under 31 trillion kilometres ....
s (509 light years) in the Lynx
Lynx (constellation)
Lynx is a constellation in the northern sky, introduced in the 17th century by Johannes Hevelius. It is named after the lynx, a genus of cat. It is a very faint constellation; its brightest stars form a zigzag line.-History:...
constellation. With an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of 10.42, the star cannot be seen with the unaided eye from the perspective of someone on Earth. The star's effective temperature
Effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation...
, at 5826 K, is hotter than that of the Sun. However, its metallicity
Metallicity
In astronomy and physical cosmology, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium...
is similar; this can be seen in how the concentration of iron, or [Fe/H], is approximately 0. WASP-13's surface gravity
Surface gravity
The surface gravity, g, of an astronomical or other object is the gravitational acceleration experienced at its surface. The surface gravity may be thought of as the acceleration due to gravity experienced by a hypothetical test particle which is very close to the object's surface and which, in...
is measured at 4.04 km/s2, while the rate at which it rotates
Rotational speed
Rotational speed tells how many complete rotations there are per time unit. It is therefore a cyclic frequency, measured in hertz in the SI System...
is at most 4.9 km/s.
WASP-13 has a mass that is 1.03 times
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
the mass of the Sun and a radius that is 1.34 times the Sun's radius. Measurements of its lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
content suggest that the star has used up all of its helium and is now fusing lithium in the shell around its core. With this, its estimated age is 8.5 billion years, over twice the age of the Sun, but this age may vary to any point between 4.4 and 14 billion years in age because of the high uncertainty surrounding this aspect of the star's age.
Planetary system
WASP-13b is a planet that orbits its host star at a distance of 0.0527 AUAstronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
, or approximately 5.27% of the mean distance between the Earth and Sun. The planet completes an orbit every 4.35298 days, or approximately 4 days and 8.5 hours. WASP-13b's estimated mass is 0.46 times the mass
Jupiter mass
Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs....
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,...
, while its radius is about 1.21 times that of the planet.