HD 73534
Star in the constellation Cancer
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HD 73534 is star with an orbiting exoplanet companion in the northern constellation of Cancer. With an apparent visual magnitude of 8.23,[3] it is too faint to be visible to the naked eye. The distance to this system is 273 light-years based on parallax measurements, and it is drifting further away with a heliocentric radial velocity of +10 km/s.[2]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cancer[1] |
| Right ascension | 08h 39m 15.803s[2] |
| Declination | +12° 57′ 37.35″[2] |
| Apparent magnitude (V) | 8.23[3] |
| Characteristics | |
| Evolutionary stage | subgiant[4] |
| Spectral type | G5 IV[3] |
| Apparent magnitude (B) | 9.192[5] |
| Apparent magnitude (J) | 6.524±0.018[5] |
| Apparent magnitude (H) | 6.072±0.020[5] |
| Apparent magnitude (K) | 5.962±0.026[5] |
| B−V color index | 0.962±0.021[5] |
| Astrometry | |
| Radial velocity (Rv) | +9.76±0.13[2] km/s |
| Proper motion (μ) | RA: −114.147 mas/yr[2] Dec.: −93.787 mas/yr[2] |
| Parallax (π) | 11.9576±0.0254 mas[2] |
| Distance | 272.8 ± 0.6 ly (83.6 ± 0.2 pc) |
| Absolute magnitude (MV) | +3.70[1] |
| Details[3] | |
| Mass | 1.228±0.060 M☉ |
| Radius | 2.39±0.16 R☉ |
| Luminosity | 3.33±0.43 L☉ |
| Surface gravity (log g) | 3.780±0.060 cgs |
| Temperature | 5,041±44 K |
| Metallicity [Fe/H] | 0.232±0.030 dex |
| Rotation | ~53 d |
| Rotational velocity (v sin i) | < 1.0 km/s |
| Age | 7.1±0.8[6] Gyr |
| Other designations | |
| Gakyid, BD+13°1956, HD 73534, HIP 42446, SAO 98004, PPM 125542[7] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Names
The star HD 73534 has the proper name Gakyid. The name was selected by Bhutan during the 100th anniversary of the IAU as part of the IAU's NameExoWorlds project. Gakyid means happiness. The planet HD 73534 b is named Drukyul, which means 'land of the thunder dragon', the native name for Bhutan.[8][9]
Properties
HD 73534 is a G-type subgiant star with a stellar classification of G5 IV. It has consumed the hydrogen at its core and begun to evolve off the main sequence, which is why it is much more luminous than the Sun. The star has a negligible level of magnetic activity in its chromosphere. It has 23% more mass than the Sun, and has expanded to 2.4 times the Sun's radius. The star is radiating 3.3 times the luminosity of the Sun from its photosphere at an effective temperature of 5,041 K.[3] It is roughly 7 billion[6] years old and is spinning slowly with a rotation period of around 53 days.[3]
Planetary system
In August 2009, it was announced that an exoplanet had been discovered using Doppler spectroscopy.[3] It is the first planetary system discovered in Cancer since that of 55 Cancri in April 1996, and the sixth planet,[citation needed] as 55 Cancri has five known planets.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.01±0.21 MJ | 2.95±0.22 | 1721±36 | 0 (fixed) | — | — |