HD 208527 is a star located in the northern constellation of Pegasus. It has a reddish hue and is dimly visible to the naked eye with an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of +6.39. The star is located at a distance of approximately 1,300 light years from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

based on parallax, and is drifting further away with a radial velocity of +4.8 km/s. This was once catalogued as a

K-type main-sequence star A K-type main-sequence star, also referred to as a K-type dwarf or an orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence star ...

with a stellar classification of K5V, but is now known as an aging red giant with a class of M1III, based on its dimensions and low surface gravity. This indicates that the two-billion year old star has exhausted the supply of hydrogen at its

core Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the centra ...

then cooled and expanded off the main sequence. It has an estimated 1.6 times the mass of the Sun but has swollen to 51 times the Sun's radius.

Planetary system

From September 2008 to June 2012, the team B.-C. Lee, I. Han and M.-G. Park observed HD 208527 with "the high-resolution spectroscopy of the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO)". In 2012, a long-period, wide-orbiting

planet A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...

was deduced by radial velocity. This was published in November, gaining the designation HD 208527 b. Along with

HD 220074 HD 220074 is a star located in the northern constellation of Cassiopeia (constellation), Cassiopeia, near the western border with Cepheus (constellation), Cepheus. It has a reddish hue and is dimly visible to the naked eye, having an ...

b this is one of the first two planets proposed around a red giant.

References

{{DEFAULTSORT:HD 208527 M-type giants Planetary systems with one confirmed planet Pegasus (constellation) Durchmusterung objects 0841.1 208527 108296 8372