This webpage gives detailed information about the recently discovered transiting planet HD149026b and the star it orbits, HD149026.
Highlights
- Planet interior models show that HD149026 has the largest core
of any known exoplanet. As shown in
this figure
the core of this planet is much larger
than that of Jupiter.
- The photometric transit depth of 0.003 mag is the smallest and most challenging exoplanet transit detection yet achieved. This is due to the relative sizes of the star and planet. Click here to see a comparison of the HD149026 system with other star/planet systems
- The orbital period of HD149026b is remarkably short, 2.88 days.
In fact, for this "Hot Saturn", an entire "year" takes
place over a single weekend!
Orbiting at a distance of just 0.042 AU, the planet's would
have a scorching temperature of 1,500 K.
- Radial Velocities of the star HD149026 not only reveal the wobble due to the planet, but also deviate from a perfect sine wave when the planet passes in front of the rotating star. This is called the Rossiter-McLaughlin effect and has been observed for other transiting planets.
Stellar Properties
| Spectral type: | G0 IV |
| Distance: | 78.9 ± 6.6 pc |
| V: | 8.15 |
| MV: | 3.66 |
| B-V: | 0.611 |
| Coordinates (2000) | |
| RA: | 16 30 29.6 |
| Dec: | 38 20 50.3 |
| Rstar: | 1.45 ± 0.1 Rsun |
| Mstar: | 1.31 ± 0.1 Msun |
| Lstar: | 2.72 ± 0.5 Lsun |
| Age: | 2.0 ± 0.8 Gyr |
| vsini: | 6.0 ± 0.5 km/s |
| Spectral Analysis | |||||||||||||||||
(From SME:
Valenti & Fischer 2005)
| Teff [K]: |
6147 ± 40 K |
Log g: |
4.26 ± 0.07 |
[M/H]: |
0.3 (0.06) |
[Na/H]: |
0.44 |
[Si/H]: |
0.31 |
[Ti/H]: |
0.34 |
[Fe/H]: |
0.36 ± 0.05 |
[Ni/H]: |
0.38 |
| |
Image Of Star HD149026, Source: POSS2
HD149026 is in the constellation Hercules in this part of the sky.
Planet Properties
| Orbital Elements | |
| P: | 2.8766 ± 0.001 days |
| Tp: | 53426.584877 JD - 2440000 |
| e: | 0.000000 (fixed) |
| K1: | 41.1 ± 1.2 m/s |
| a: | 0.042 AU |
| a1sini: | 1.037e-5 AU |
| f1sini: | 1.839e-11 Msun |
| Mass_Fn: | 2.4899179e-11 Msun |
| M2: | 0.36 MJUP |
| Nobs: | 11 |
| Rmv: | 5.0 m/s |
| Reduced sqrt(χ |
0.97 m/s |
| Rplanet: | 0.72 ± 0.06 RJup |
| Planet temp: | 1500K |
Ephemeris Times
(Provided by Prof. Greg Laughlin &
Transitsearch.org)
Artist's Concept of HD149026 and planet.
(Artwork by Lynette Cook)
Planet Core Comparison