Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Pegasus |
Right ascension | 21h 56m 23.984s [1] |
Declination | +21° 14′ 23.49″ [1] |
Apparent magnitude (V) | +6.39 [2] |
Characteristics | |
Spectral type | M1III [3] |
B−V color index | 1.698±0.002 [2] |
Astrometry | |
Radial velocity (Rv) | +4.79±0.06 [3] km/s |
Proper motion (μ) |
RA: 1.433
mas/
yr
[1] Dec.: 14.675 mas/ yr [1] |
Parallax (π) | 3.0302 ± 0.049 mas [1] |
Distance | 1,080 ± 20
ly (330 ± 5 pc) |
Absolute magnitude (MV) | –1.24 [3] |
Details [3] | |
Mass | 1.6±0.4 M☉ |
Radius | 57.6±6.5 [4] R☉ |
Luminosity | 729±30 [4] L☉ |
Surface gravity (log g) | 1.6±0.3 cgs |
Temperature | 4,035±65 K |
Metallicity [Fe/H] | −0.09±0.16 dex |
Rotational velocity (v sin i) | 3.6 km/s |
Age | 2±1.3 Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
HD 208527 is a star with an orbiting exoplanet 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 of +6.39. [2] The star is located at a distance of approximately 1,080 light years from the Sun based on parallax, [1] and is drifting further away with a radial velocity of +4.8 km/s. [3]
This was once catalogued as a K-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. [3] This indicates that the two-billion year old star has exhausted the supply of hydrogen at its core then cooled and expanded off the main sequence. It has an estimated 1.6 [3] times the mass of the Sun but has swollen to 58 times the Sun's radius. The star is radiating 729 [4] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,035 K. [3]
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)". [3]
In 2012, a long-period, wide-orbiting exoplanet was deduced by radial velocity variations. This was published in November, gaining the designation HD 208527 b. Along with HD 220074 b this is one of the first two planets proposed around an M-type red giant. [3]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥9.9±1.7 MJ | 2.1±0.2 | 875.5±5.8 | 0.08±0.04 | — | — |