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Exoplanetary Scratchpad

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Hot Jupiters whose day sides and night sides show stark contrast in temperatures. These planets lack the supersonic winds that cause some Hot Jupiters to have uniform temperatures. Heat may somehow be shed to outer space quicker than it can be transported to the other side of the star. Upsilon Andromedae b is the first confirmed case.

Fire and Ice Hot Jupiters Web Pages[]

Fire and Ice Hot Jupiters In the News[]

Sample (Year)[]

Example Systems[]

  • Upsilon Andromedae System - Titawin (Upsilon Andromeadae) is a nearby (44 ly) multi-star system which is the first multiplanet system found around a main sequence star or a multi-star system. The main star around which the planets orbit is a yellow-white star somewhat younger than the sun and its companion is a red dwarf in a wide orbit. It is one of the most well studied non-transiting star systems. Roaster Saffar (b, 0.05 au, 0.62 MJ, e=0.013, and the nearest true Hot Jupiter to Earth) is nicknamed the Fire and Ice Planet because it is hot on one side and cold on the other. The hottest parts of the planet are near the trailing side terminator at the equator, due to high velocity winds transporting heat to the night side. This is 80deg offset from the starward pole and a much greater offset than other observed hot Jupiters. This threw astronomers off and caused them to doubt the wind-theory, though later observations of other planets have shown that winds indeed can travel fast enough to cause this. Stability studies and observations suggest its diameter is 1.8 DJ, rather large for a planet its age. The middle planets Samh (c, 0.83 au, 1.8 MJ, initially thought to possibly be a brown dwarf star, e=0.224) and Majriti (d, 2.5 au, 10.2 MJ, e=0.26) have had their inclinations and masses determined with astrometry, the first determination of relative inclinations of exoplanets. They are very eccentric and highly inclined to each other (30 deg). Planet scattering was thought to be a source until the outermost planet was discovered. This is planet e (5.2 au, 1.05 MJ, e = 0.005), which is the most Jupiter-like exoplanet known, and is in 3:1 resonance with planet d. Planet c is in the habitable zone, though any habitable moons would see drastic temperature swings. The star appears to have no Kuiper-belt like disc, perhaps due to its companion star sweeping away this material. One of the first 20 exoplanet systems allowed to be given common names by the IAU. The star is named after an important city in Morocco that bridged the Spanish and Arab worlds. The planets are named after famous Andalusian astronomers.
  • 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.

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