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Exoplanetary Scratchpad

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Ammonia Cloud Jovians and Neptunians are giant planets whose visible cloud decks are dominated by ammonia compound clouds. This is a list of systems containing Ammonia Cloud Jovians (or Jupiter Twins) as identified on Extrasolar Visions. This list may be updated to incorporate new science and discoveries. For a list of those exactly seen on Extrasolar Visions, see EV Ammonia Cloud Giants.

Jupiter Twins[]

  • Solar System - Home system of Earth, the only confirmed habitable planet. Also has three other terrestrials, two Jovians, two Neptunians, several rocky and icy Dwarf Planets, a asteroid belt, a kuiper belt, and an Oort cloud.
  • HD 70642 System - First Jupiter analog discovered in a system with no giant planets further in, making it the closest solar system analog. Planet is 3.3 AU from an aging yellow dwarf star 90 light years away.
  • HD 128311 System - An orange dwarf star with two jovians (a Jupiter analog detected in 2005 and an eccentric giant in the outer habitable zone) possibly in 1:2 resonance and a dusk disk detected by Spitzer.
  • 47 Ursae Majoris System - Chalawan (aka 47 Ursae Majoris) is solar analog (G1 V, about the same age as the Sun) with 3 planets 46 ly away. One of earliest systems discovered. Taphao Thong (b, 2.5 MJ, 2.1 AU) and Taphao Kaew (c, 0.5 MJ, 3.6 AU) are in circular orbits at asteroid-belt like distances, while planet d (1.6 MJ, 11.6 AU) is in a distant more eccentric orbit (0.16, 9.6-13 AU). Planet b was the first found to have a circular orbit beyond the habitable zone. The discovery of planet c made the system the first multiplanet system whose planets have circular orbits, and b and c are rough Jupiter-Saturn analogs in relative size and positions. Their existence was in doubt until planet d was discovered. Planet d has not yet completed a full year (38.4 years) yet since its discovery (it cannot be named yet), but is the furthest out planet discovered with the dopplar spectrometry method. Studies have shown a terrestrial planet could only form in the innermost part of the habitable zone. Several transmissions have been sent to the star system. One of the first 20 exoplanet systems allowed to be given common names by the IAU. Star named after a Thai crocodile asterism and its planets are associated with two sisters associated with this legend. Taphao Thong was captured by the crocodile, while her sister Taphao Kaew married the one who rescued her.
  • HD 117207 System - A jupiter analogue 3.8 AU from a yellow dwarf star.

Ammonia Cloud Jovians[]

  • HD 37124 System - The fourth triple planet system discovered around a normal star, the last one announced with 4 other multiplanet components in 2005. A Sunlike star with Jovian planets that received Venus-like, Mars-like, and Asteroid Belt-like radition from their stars. Simulations showed that no terrestrial planets could form between the Venus-like and Mars-like Jovian planets.
  • Solar System - Home system of Earth, the only confirmed habitable planet. Also has three other terrestrials, two Jovians, two Neptunians, several rocky and icy Dwarf Planets, a asteroid belt, a kuiper belt, and an Oort cloud.

Eccentric Ammonia Cloud Jovians[]

  • Gliese 777 System - Outer planet of the primary star was initially believed to be a Jupiter analog, but later found to be eccentric (its apastron is at Jupiter-like distance). Its second planet was the fourth Neptunian discovered and was announced with four other "second" planets in 2005.
  • HD 30177 System - An eccentric ammonia cloud jovian orbiting 2.7 to 5.0 AU from a yellow dwarf star.
  • 55 Cancri System - Copernicus is also known as Rho Cancri, 55 Cancri, Rho1 Cancri, HR 3522, Gl 324, and HD 75732. Wide binary star consisting of a sun-like primary (A, though super metal rich) and a red-dwarf secondary (B) separated by 1,100 AU, 41 light years away. Star A contains five exoplanets, the first system found with four or five planets. It has three tightly packed eccentric planets close in to the star, including planet Jannsen (e, hot Super Earth/Neptunian), Galileo (b, warm Jupiter), and Brahe (c, hot Saturn), followed by an eccentric Saturn in the habitable zone (Harriot, f) and a Jupiter analog, Lippershey (d). Planet e was heralded as the first Neptunian discovered. It was later found to be the shortest-period planet discovered (18 hours) and to transit. Its density was measured and determined to be rocky, and thus re-dubbed the first Super-Earth discovered. It was then the first super-Earth to have its light detected (by Spitzer in the infrared). The planet has about half of Neptune's mass, but is Earth-like in size and density (2.17 Earth Radius). Studies taking into account the composition of the star suggested that it was largely made of diamond, with graphite at the surface (the first diamond planet around a Sunlike star), and the first terrestrial found with fundamentally different surface composition and processes than Earth. This was later refuted when it turned out there wasn't as much carbon in the parent star as believed. Earlier studies that assumed an Earth-like composition suggested that it would be covered with an ocean of super-critical water. The brightness of the planet was found to have raised dramatically, possibly the aftermath of cloud cover due to a volcanic eruption. The brightness of the star (also closest known to transit and only known naked eye star to do so) makes it more easily studied than other hot super Earths. It was found to be dark and its sun-facing side hot enough to melt metal. It became the first super Earth to have its atmospheric composition measured (mostly hydrogen and helium with hints of hydrogen cyanide which would only dominate in a carbon-rich environment and no traces of water vapor) and temperature mapped, and the large hemispherical temperature differences suggest little atmosphere to transport heat. Planet b (one of the original 4 Hot Jupiters discovered) is the first "warm Jupiter" found to have a puffed up atmosphere and it probably at the outer limit from the star at which a planet can lose its atmosphere in this way. Its outer atmosphere skims the surface of the star, which was detected when attempting to detect an atmosphere around transiting Janssen. The strong interaction between planets Galileo and Brahe can be detected in measurements, and it took a while to find a fit that would allow them to survive over long periods of time. Harriot is a very eccentric Saturnian in the habitable zone. Planet d is a super jovian at Jupiter-like distances, which was the first found at true Jupiter distances and still the exoplanet discovered with dopplar spectrometry with the largest known semi-major axis. It was first thought to be circular, then eccentric, and then circular again. The distant outer star causes Lippershey's axis to flip on its axis every million years. Lippershey in turn causes the other planets to flip, including its star. The axis tilt of transiting planet e should be determined at some point. "Bode's law" predicts four undiscovered planets. One of the first 20 exoplanet systems allowed to be given common names by the IAU.
  • HD 33636 System - One of the six extrasolar systems thought to have planets to be first shown to also have a dust disk by Spitzer. The "planet" was later shown to be a star.
  • Epsilon Eridani System - Ran (Epsilon Eridani) is the nearest single non-red dwarf star to the Sun, also known as HD 195019, Gl 144, and HR 1084. It is a member of the Ursa Major star association and close encounters to other stars is relatively common. One of the first stars found to have a dust disk, with several potential planets suspected in the gaps early on, and later on of the earliest nearest system with confirmed planets. Has an inner asteroid belt at 3 AU, Jovian planet AEger at 3.4 AU, outer asteroid belt at 20 AU, and Kuiper Belt at 35-100 AU. A planet is proposed to be just outside the outer asteroid belt, and another just before the Kuiper belt.Because the star is very chromospherically active, doubts were cast on planet's b's existence. Hubble then confirmed its existence with astrometrics and found to be orbiting in the plane of the dust disks, which supported the theory that planets are born from dust disks and yielded a precise mass of 1.5 MJ. The planet b was originally thought to be extremely eccentric (2-10 AU), but later discovery of the inner asteroid belt suggests it is more moderately eccentric so as not to cross the belt. It could still have high eccentricity if the outer belt was being fed with material from the outer belt though. Dinosaur-killing sized impacts would be frequent on any Earth-like planets, about once every 2 million years. One of 5 PICTURE-C targets selected for sub-orbital coronograph observation. One of the first 20 exoplanet systems allowed to be given common names by the IAU. Star is named after a Norse goddess of the seas, while the planet after her husband, god of the ocean. A common sci fi system, including the original home of Star Trek Vulcans (though this moved to 40 Eridani) and Babylon 5.
  • Mu Arae System - Cervantes (Mu Arae) is a 6th magnitude Sunlike star close to becoming a Sub-Giant located 50 ly with four known planets. At first believed to be a system dominated by orbit crossing eccentric Super Jupiters. Instead, three Jovians orbit in roughly circular orbits at Earth-like (Rocinante, d), Mars-like (Quixote, b, in habitable zone), and Jupiter-like (Sancho, e) distances in addition to an inner (Dulcinea, c) Hot Neptune. Planet c was one of three Hot Neptunes or Hot Super Earths discovered around the same time. It was the first one announced, but it was still under scientific review at the time, so there remains controversy on what the actual first planet discovered of this class is. Initially thought to likely to be rocky because it had 2 known neighboring gas giants which may have stunted its growth. The characteristics of the planets in this system changed greatly as new planets were discovered, and included a re-ordering of their designations. Initially, the first planet b was thought to be highly eccentric. An outer planet was then detected, at the time dubbed "c" (though a full period hadn't yet been observed), and was thought to have an extremely high eccentricity so that the orbits of the two planets would cross. An innermost third planet then dubbed "d" was then detected. A new fit for the data then emerged, and it was found that the outermost planet was actually much less eccentric, and that there was a planet interior to planet b with almost half its period. The eccentricity of b was also reduced so that no planet criss-crossed another's anymore. It was decided to redesignate the planets in order of characterizations instead of by discovery, so the innermost Neptunian planet was re-dubbed "c" and the planets just interior and exterior to planet "b" were re-dubbed "d" and "e". The system became the second known 4-planet system. The innermost two Jovians are close enough so that they're unstable over short periods of time. If they were actually in 1:2 resonance, which almost fits the data, they would be much more stable. One of the first 20 exoplanet systems allowed to be given common names by the IAU. Star is named after the author of Il Ingenioso Hildalgo Don Quixote de la Mancha and the planets after its characters, Quijote (main character), Dulcinea (love interest), Rocinante (horse), and Sancho (squire).
  • 14 Herculis System -
  • HD 89307 System - A moderately eccentric ammonia cloud jovian around a yellow dwarf star.