HD 15082 (also known as WASP-33) is a

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

located roughly 399

light year 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 ...

s away in the northern constellation of Andromeda. The star is a Delta Scuti variable and a planetary transit variable. A

hot Jupiter Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter but that have very short orbital periods (). The close proximity to their stars and high surface-atmosphere temp ...

type extrasolar planet, named

WASP-33b WASP-33b is an extrasolar planet orbiting the star HD 15082. It was the first planet discovered to orbit a Delta Scuti variable star. With a semimajor axis of and a mass likely greater than Jupiter's, it belongs to the hot Jupiter class of pla ...

or HD 15082b, orbits this star with an orbital period of 1.22 days. It is the first Delta Scuti variable known to host a planet.

Spectrum

HD 15082 is an Am star, which makes its

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

challenging to discern. The

hydrogen lines The emission spectrum of atomic hydrogen has been divided into a number of spectral series, with wavelengths given by the Rydberg formula. These observed spectral lines are due to the electron making transitions between two energy levels in an ...

and

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. Effective temperature is often used as an estimate of a body's surface temperature ...

of the star are similar to spectral type A8, however the calcium II K line resembles that of an A5 star, and the metallic lines are more similar to an F4 star. The spectral type is written kA5hA8mF4.

Pulsations

Delta Scuti variables usually exhibit many pulsation modes, and HD 15082 is no exception, with 8 measured high frequency p-modes. Another proposed non-radial mode, which could be induced by tidal interactions with the planet, would make this star also a Gamma Doradus variable. This star has the GCVS variable star designation V807 Andromedae.

Planetary system

In 2010, the

SuperWASP WASP or Wide Angle Search for Planets is an international consortium of several academic organisations performing an ultra-wide angle search for exoplanets using transit photometry. The array of robotic telescopes aims to survey the entire sky, ...

project announced the discovery of an extrasolar planet, designated

, orbiting the star. The discovery was made by detecting the

transit Transit may refer to: Arts and entertainment Film * ''Transit'' (1979 film), a 1979 Israeli film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world * ''Transit'' (2006 film), a 2006 ...

of the planet as it passes in front of its star, an event which occurs every 1.22 days.

Notes

References

{{DEFAULTSORT:HD 15082 Andromeda (constellation) 015082 011397 A-type main-sequence stars Delta Scuti variables Andromedae, V807 Planetary systems with one confirmed planet Planetary transit variables Durchmusterung objects 33 J02265106+3733017V807