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Exoplanetary Scratchpad

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Hot Jupiters that are larger than theoretical models predict for their temperature and mass. Also called "puffed up", "puffy", or "bloated" planets. May be larger than Hot Saturns (similar density to Saturn) or also be Hot Saturns.

Inflated Hot Jupiters Web Pages[]

Inflated Hot Jupiters In the News[]

Sample (Year)[]

Example Systems[]

First Discovered[]

  • HD 209458 System (1st found) - Has first discovered transiting planet which was nicknamed Osiris due to the (first detected) comet-like tail detected and the first exoplanet around a normal star to have its mass directly measured. Also the first Inflated Hot Jupiter found. The planet may be losing its outer atmosphere, or magnetism may prevent the ions from escaping. They detected water in its atmosphere (they had failed earlier), the first time this has been done for any exoplanet. 2nd Exoplanet with detected organic compounds; like HD 189733b, it has water and carbon dioxide, but it has a lot more Methane. Was one of 2 planets to have light directly taken and thus their temperatures read (over 1000K). Tracking carbon molecules with dopplar spectrometry caused it to be the first exoplanet detected to have winds, which are raging at 5,000 to 10,000 km/h. This is believed to cause hotspots to appear at terminators rather than at the star-ward facing point. Had one of the strongest water detection of the 5 exoplanets contrasted by Hubble in 2013, though still less intense than expected, probably due to dust clouds or a haze blocking its detection.
  • HAT-P-1 System (2nd found) - A stellar binary believed to contain the planet with the biggest known diameter and the least dense. This would have been only the second planet with such a low density. Later measurements showed it wasn't that inflated, and has the expected radius for a highly irradiated core-less Hot Jupiter.
  • WASP-1 System (third found) - Has the first planet detected by the WASP program, which is the third "inflated" Hot Jupiter detected, which suggested these planets were fairly common. It was nicknamed "Garafía-1" after the municipality that hosts the Roque de Los Muchachos Observatory. Was the largest known exoplanet for about a year. Shows signs of atmospheric blow-off.

Other Examples[]

  • WASP-6 System - An inflated sub-Jupiter mass planet (50% Jupiter's mass, 22% more radius) orbiting a solar type star. Hubble studied its atmosphere.
  • HAT-P-7 System - F8 star also known as GSC 03547-01402 containing a transiting Hot Jupiter and an outer Jovian and a further out stellar companion. Transiting planet was used as a test for the Kepler mission (dubbed Kepler 2), which was able to detect the planet's occulation, as well as evidence of phases. Very little of its heat is transported to its night side, with its hottest spot being 1,300 F hotter than its coldest spot. Extremely strong easterly winds are produced as a result, but the planet's magnetic field has been shown to disrupt the direction of these winds at some times. This is because the high temperatures strip electrons from the atmospheric atoms of lithium, sodium, and potassium, making them positively charged, which follow the magnetic field lines. The stronger field lines may completely reverse the direction of the winds. Variation in brightness has been thought to be due to clouds of corundum (which emeralds and sapphires are made of) being blown into the dayside by the winds and then dissipating in the intense heat. Its atmosphere could be made up of exotic gases like Titanium Oxide. The Hubble Space Telescope made its 1,000,000th science observation on this planet in the attempt to detect water in its atmosphere. The planet may "lift" its stars surface up gravitationally, reducing its temperature a fraction of a degree in a darkened spot that lags a few hours behind the planet. It was found by a Japanese team to be orbiting backwards only a day after the first retrograde exoplanet WASP-17b was announced. The Japanese team inspected two stars nearby, measured their proper motions, and found that one of them was a member of the system. They also confirmed an outer radial velocity detected Jovian between the planet c and companion star B. Star B is suspected of tilting planet c's orbit, which in turn affected planet b's orbit and caused it to orbit backwards.
  • WASP-15 System - One of the 6 out of 27 planets analysed by the WASP team found to orbit backwards around its star in 2010. Contains one of the least dense known exoplanets.
  • WASP-12 System - The shortest period transiting Hot Jupiter known when discovered in 2008 and the first carbon-rich planet ever found (more Carbon than Oxygen). One of the two largest known planets at 1.79 Jupiter radii. Hottest known exoplanet at time of its discovery. Planet is being ripped apart by star. It is stretched in the shape of a rugby ball and leaves a ring around its star. Huge cloud of material detected around the planet containing elements never before detected on an exoplanet. This cloud is much larger than expected, and shrouds the entire star, making it undetectable at some wavelengths. Studying this cloud could reveal magnetic properties of the stellar system. Magnesium found in this shroud supports the blow-off theory where Hydrogen escapes from the planet so quickly other material is blown off with it. Two other Hot Jupiters are known to have planetary enveloping clouds, and others as close are expected to have similar system wide clouds, but not those further away. It has much more methane than water vapor. It may produce shock waves as it plows through its star's stellar wind (the first evidence of shocks around an exoplanet, like Earth and Saturn's bowshocks), possibly produced by a strong planetary magnetic field. This could protect its atmosphere from being stripped away. It could have a diamond core and other terrestrial planets in system would have black spots on them and also be carbon based. One of 5 exoplanets whose water abundance was measured by Hubble in 2013 and found to be less abundant than expected, probably due to a layer of haze or dust blocking detection..

See Also[]