HAT-P-4 b
From Wikipedia, the free encyclopedia
| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
| Parent star | ||
| Star | BD+36º2593 | |
| Constellation | Boötes | |
| Right ascension | (α) | 15h 19m 58s |
| Declination | (δ) | +36° 13′ 47″ |
| Distance | 1010 ± 100 ly (310 ± 30 pc) | |
| Spectral type | F | |
| Orbital elements | ||
| Semimajor axis | (a) | 0.0446 ± 0.0012 AU |
| Eccentricity | (e) | 0 |
| Orbital period | (P) | 3.056536 ± 0.000057 d |
| Inclination | (i) | 89.9-2.2+0.1° |
| Angular distance | (θ) | 0.044 mas |
| Longitude of periastron |
(ω) | 12.33° |
| Time of periastron | (T0) | 2,454,245.8154 JD |
| Semi-amplitude | (K) | 76.93 m/s |
| Physical characteristics | ||
| Mass | (m) | 0.68 ± 0.04 MJ |
| Radius | (r) | 1.27 ± 0.05 RJ |
| Density | (ρ) | 410 ± 60 kg/m3 |
| Surface gravity | (g) | 1.11 m/s² (10.9 g) |
| Discovery information | ||
| Discovery date | Oct 2, 2007 | |
| Discoverer(s) | Kovacs et al. | |
| Detection method | transit | |
| Discovery site | Mass., USA | |
| Discovery status | Published | |
HAT-P-4b is an extrasolar planet orbiting the star BD+36º2593 over 1000 light years away in Boötes constellation. It was discovered by transit on October 2, 2007, which looks for slight dimming of stars caused by planets that passed in front of them. It is the fourth planet discovered by the HATNet Project.
It is a typical hot Jupiter with 68% the mass and 127% the radius of Jupiter, and 41% the density of water (31% of Jupiter). Since the inclination is known by transit observation, the true mass is known.
The planet orbits at 22.4-1 times the distance of Earth to the Sun, or 6.67 gigameters from the star. The period of this planet is exactly 73 h 21 m 24.71 s. The combination between small orbital circumference and short orbital period will yield a fast average velocity of 158.55 km/s or 98.46 mi/s.
Combining this planet with very small orbit, jovian mass, and supersolar-mass parent star will yields a stellar wobbling velocity of 76.93 m/s, which makes complete wobbling in 0.264 Ms, exactly the same as the orbital period of the planet. This finds the circumference of wobble's path as 20.316 Mm and the radius is 3.233 Mm. The ratio between stellar wobble and the orbiting planet is 1:2063.
[edit] References
- G. Kovacs, G. A. Bakos, G. Torres, A. Sozzetti, D. W. Latham, R. W. Noyes, R. P. Butler, G. W. Marcy, D. A. Fischer, J. M. Fernandez, G. Esquerdo, D. D. Sasselov, R. P. Stefanik, A. Pal, J. Lazar, I. Papp, P. Sari (2 Oct, 2007). "HAT-P-4b: A metal-rich low-density transiting hot Jupiter".
