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| Exoplanetary Scratchpad|
Hat-P-2b (aka HD 147506b) is the most massive measured exoplanet discovered that is clearly not a Brown Dwarf and the first transiting Hot Super Planet discovered. It is the first known transiting planet with a significantly eccentric orbit and experiences significant seasons. It briefly held the record of furthest out transiting planet.
HD Hat-P-2 System Web Pages
HD Hat-P-2 System Artwork
HD Hat-P-2 System In the News
Massive Planet Discovered (2007)
HAT-P-2b: A Super-Massive Planet in an Eccentric Orbit - Extrasolar Visions BBS Thread
http://dsc.discovery.com/news/2007/05/07/fatplanet_spa_zoom0.html?category=space&guid=20070507093000 HAT-P-2b: ‘A Really Weird Planet’ - Centauri Dreams BLOG
Atmosphere Modelled (2007)
Parameters Refined (Jun 2007)
HD Hat-P-2 System Fun Links
- 440 light years away
- Hot star with one or two planets
- In the constellation Hercules
- 4th brightest star that has a transiting planet
- Visual Magnitude of 8.7, visible in small 3 inch telescopes
- 2.7 Giga years old
- Almost twice as large as the Sun (1.8 RS)
- Mass is 1.3 MS.
Hat-P-2 Star Factoids
- Star is also known as HD 147506.
- A hot White Main Sequence Star (F8 V)
- Almost twice as big as the Sun.
Planet b Factoids
- Planet so unusual that its discoverers at first thought it was a false alarm.
- The most massive measured planet discovered so far.
- Nicknamed "the heavyweight champion of extrasolar planets".
- When first discovered, it was thought its Mass was 8.17 MJ and Radius 1.18RJ.
- When first discovered, it was believed its density was as great as a terrestrial planet (6.6 gcm^-3, even though it is likely made up of hydrogen and helium.
- Updated measurements give it Mass of 8.64 Jupiter, radius of 0.954, and an even higher density of 12.41 g cm^-3.
- Density is now between that of a typical hot jupiter (1 g cm^-3) and low mass star (50 g cm^-3).
- Updated surface gravity is 227 m s^-1.
- Its measurements conform to current theory
- The first discovered transiting planet that is not a Hot Jupiter. This is much larger and denser than a Jupiter class planet.
- If it had 50% more mass, it would start limited fusion and be a Brown Dwarf.
- Has greatest surface gravity of any measured planet, 14 time's Earth's.
- Per earlier measurements, a 150 pound person would weigh 2100 pounds on its cloud tops.
- Per earlier measurements Surface gravity is 5 times that of any other transiting exoplanet.
- If Earth's orbit was as eccentric, it would extend from Mercury to Mars.
- Orbits in an eccentric orbit near its star (e = 0.5).
- No other known planet is as close in with such a high eccentricity (all other transiting planets are rather circular).
- Its short period of 5.63 days is actually the longest of all known transiting planets and its transits last longer than any other.
- Ranges from 0.03 AU to 0.1 AU (a = 0.06 AU)
- The difference in heat it receives from its star is 9 times from periastron to apastron.
- Temperatures range from 1000 C to 2000 C.
Hypothetical Outer Planet
- An outer planet could explain the great eccentricity of planet b
- There is no other evidense supporting or refuting this planet's existance
Map of HD 147506 System
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