HD 147506
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| Observation data Epoch J2000.0 |
|
|---|---|
| Constellation (pronunciation) |
Hercules |
| Right ascension | 16h 20m 36.36s |
| Declination | +41° 02′ 53.1″ |
| Apparent magnitude (V) | +8.7 |
| Characteristics | |
| Spectral type | F8V |
| U-B color index | ? |
| B-V color index | ? |
| Variable type | none |
| Astrometry | |
| Radial velocity (Rv) | ? km/s |
| Proper motion (μ) | RA: −10.64 mas/yr Dec.: −29.70 mas/yr |
| Parallax (π) | 7.39 ± 0.88 mas |
| Distance | 440 ly (135 pc) |
| Absolute magnitude (MV) | +3.04 |
| Details | |
| Mass | 1.298 ± 0.1 M☉ |
| Radius | 1.412 ± 0.04 R☉ |
| Surface gravity (log g) | 4.33 |
| Luminosity | 2.79 L☉ |
| Temperature | 6290 ± 110 K |
| Metallicity | +0.12 ± 0.08 |
| Rotation | ? |
| Age | 2.7 ± 1.4 × 109 years |
| Other designations | |
HD 147506 is a magnitude 8.7 F8 dwarf star that is somewhat larger and hotter than our sun. The star is 440 light years from Earth and is positioned near the keystone of Hercules. It is estimated to be 2 to 3 billion years old.
[edit] Planetary system
Orbiting the star is HAT-P-2b, the most massive transiting extrasolar planet yet discovered. [1] At 9.04 MJ and an estimated surface temperature of ~900 kelvins, on a 5.6 day orbit, this planet is unlike any previously discovered transiting planet. The planet has a large mass (nine times the mass of Jupiter), and a surface gravity 25 times that exerted by the Earth. Its orbital eccentricity is very large (e = 0.5). Since tidal forces should have reduced the orbital eccentricity of this planet it is speculated that another massive planet found outside the orbit of HAT-P-2b is in orbital resonance with HAT-P-2b. [2]
The planet was discovered by the HATNet Project and the researchers there believed the planet to be 10-20% larger than Jupiter. This discovery is important as it provides further support for the existing theory of planetary structure. [3]
- Name HD 147506 b
- Mass: 9.04 (± 0.50) MJ
- Semi major axis: 0.0685 AU
- Orbital period: 5.63341 (± 0.00013) days
- Eccentricity: 0.520 (± 0.010)
- Radius: 0.982 (+0.038-0.105) RJ
- Inclination: 90 (± 0.8) deg
[edit] See also
[edit] References
- ^ Extrasolar Planet Encyclopaedia
- ^ Alan MacRobert, “New Worlds roundup,” Sky and Telescope, August 2007, pg 15.
- ^ Systemic Planetary Simulation
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