| Exoplanetary Scratchpad|
- PSR B1620-26 System - A helium white dwarf and a pulsar in the middle of the crowded core of the M4 star cluster, around which , the oldest known planet, nicknamed "Methuselah, orbits. It was formed only 1 Billion Years after the big bang and is 13 Billion years old. The planet may be a brown dwarf.
Early Dopplar Pioneer SystemsEdit
- 51 Pegasi System - The star called 51 Pegasus is now known as Helvetios. Contains the first exo-planet around a normal star discovered and the first "Hot Jupiter" found, which is nicknamed "Bellerophon", and now called Dimidium. Star is about 50 ly located in the square of Pegasus, a G5 star somewhat larger and more massive than the Sun. The planet's discovery was incompatible with planetary system formation models, so they were tweaked to allow for planetary migration. It was also initially thought to be an anomaly or the stripped down core of a brown dwarf. Found to have supersonic winds that caused the eternal night-side hemisphere to be as hot as the day-side one. During its 20th anniversary, this planet became the first one's whose reflected visible light was detected. The technique involved looking at a star's visible spectrum, and then detecting a faint reflection of this spectra. Its actual mass (0.46 MJ) and inclination (9deg) were obtained as a result. The planet seems to have a larger radius and bright surface, rather typical for hot jupiters. One of the first 20 exoplanet systems allowed to be given common names by the IAU. The star's name is Latin for a Celtic tribe that lived in Switzerland (the place where its planet was discovered) during the middle ages. The planet's name is Latin for "half" due to the fact its minimum mass is half as massive as Jupiter's.
- 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.
- 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.
- Tau Bootes System - (aka Tau Bootis) Contains one of the first four discovered Hot Jupiters, which was one of the largest, hottest, closest in (P = 3.3d, a = 0.05) of the earlier discovered ones and the closest known at the time and is today one of the brightest planets known. It was immediately recognized to have tidally locked its star's rotation period. The star (also known as HR 5185) is nearby (50 ly), 1.5 times as massive as the sun. The planet does not transit its star, but is one of the brightest planets known. Several attempts to detect light were declared, but then refuted. In one such attempt by British astronomers, it was nicknamed the "Millenium Planet", and light was thought to have been detected (thought to be a first) by subtracting its star's light, giving an inclination of 29deg, mass of 8 MJ, and size of 1.8 RJ, and blue-green color. NASA's Spitzers later was thought to have detected it (again, a believed first, considering visually detected ones were planetary "candidates"). It was finally detected later by observing CO lines produced by reflected light through its atmosphere, yielding a mass of 6 MJ and inclination of 44F. Water was later also detected in its atmosphere in the near infra-red, the first for any non-transiting exo-planet. The temperature was unexpectedly found to be cooler at the upper levels, unlike many other hot Jupiters (strong ultraviolet radiation are thought to destroy the compounds responsible for creating thermal inversions in this case). The star was the first to have its magnetosphere detected (which envelopes the planet) and also the first known to magnetically flip like the Sun (flips once every Earth year, vs the Sun's 11 years). One of the first 20 exoplanet systems allowed to be given common names by the IAU, but the only one whose chosen name was rejected because it did not conform to IAU's naming standards.
- HD 209458 System (1999) - 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.
- OGLE-TR-56 System (Nov 02) - Contains first planet discovered by transit and later confirmed by Dopplar Spectroscopy (rather than the other way around). The first OGLE planet confirmed with the Dopplar method. It is 6000 ly away, 10 times as far as any previous known planet, in a different arm of the galaxy. Also the first Very Hot Jupiter and the first non-inflated Hot Jupiter discovered. It may meet its doom in less than a million years. Planet has one of the first two ground-detected atmospheres. Has an atmosphere hotter than any other measured so far. Unlike other hot Jupiters observed, it is way too hot for clouds of silicon or iron to form which would keep it dark.
- TrES-1 System (Mar 05) - Contains the first transiting exoplanet discovered with the TrES amateur equipment and second transiting exoplanet close enough to have its atmosphere studied. It is the first Hot Jupiter that had the expected radius. Was the one of the first two exoplanets to have its light separated from its host star. Has a cloud or torus of particles around it. Tidal heating is predicted due to its eccentric orbit, but this has not seem to have inflated its radius.
- HD 189733 System (Dec 05) - A binary star in Velpulca (the "little fox") consisting of an Orange Dwarf star A and a Red Dwarf B (discovered shortly after planet Ab found and orbiting perpendicular to that planet's orbit and later detected in x-rays) orbiting 216 AU away. Planet Ab (the first nearby Very Hot Jupiter, originally thought to be inflated, is 13% larger and more massive than Jupiter) is the nearest transiting Hot Jupiter (62.9 ly). This is the first exoplanet to have its temperature mapped and was nicknamed Bull's Eye for its hot spot that is significantly offset from the starward pole. 5 years later, it later became the first world to have its thermal emissions mapped in both longtitude and latitude, confirming the hot spot was near the equator. Fast winds are thought to make the temperature of the eternal day and night sides nearly identical, which were later measured to be 2km/s when the planet became the first to have its wind and weather patterns mapped. It is also the first exoplanet for which scattered light in the upper atmosphere has been detected and the second exoplanet with water detected and first with Methane and then Carbon Dioxide detected. It later was the first exoplanet whose gasses were detected from Earth-based telescopes. It was also found to spin up its star and magnetically interact with it, causing stellar storms. Massive X-class solar flares blast off much of the planet's atmosphere and may render it undetectable. Hubble found that its atmosphere was a uniform blue haze. Blue was detected by determining which wavelengths were blocked during a transit. It was also found to rain molten glass, sideways, with 7000 km/hr winds and 1000C. It became the first exoplanet whose transit was detected in X-Rays, which revealed it had a very large extended outer atmosphere, which is losing material rapidly. The star is much more magnetically active for its age, possibly due to the planet's presence. There is speculation that it could have large planet-wide auroras. It's already-known mass was measured using an atmospheric pressure method to test its viability. By studying sodium spectra, it was determined that it gets hotter with altitude.
- TrES-2 System (Sep 06) - Contains TrES-2, which was the most massive nearby transiting planet until the discovery of Hat-P-2 b. It has a large radius for a planet not considered inflated. A large ground-based telescope method of observation was pioneered on this planet. Since its in Keplar's field of view, it was observed by it as a test subject and dubbed Kepler1b. A second planet is possibly responsible for fluctuations in the first's inclination. Kepler determined that it is the darkest known planet, blacker than coal, due to its extremely low dimming and brightening detected during transits. It would appear black except for some faint red tinge. This conflicts with current theories, which thought that a Hot Jupiter could only get as dark as Mercury. It appears that the planet is too hot for reflective clouds to form and instead its atmosphere contains light-absorbing chemicals. An off-the-cuff nickname Erebus (Greek god of darkness) has been suggested. It was also the first planet whose phases have been detected.
- Gliese 436 System (May 07T) - AC+27°28217 is best known as Gliese 436. The second known red dwarf planetary system. Contains one of the first Neptunians discovered and a few potential planets. The star is about half the sun's mass. It is over 11 Billion years old and may be a part of the old disk of the Milky Way. Planet b temporarily later found to be the smallest exoplanet (about Uranus' diameter, though over 50% its mass) known to transit its host star and is currently the nearest (33 ly). Its temperature (712K) was measured to be higher than what it would be purely from radiation (520K), perhaps due to a greenhouse effect, somewhat higher than Venus. It was originally thought to have a layer of "hot ice", water solidified due to high pressures. It turned out that it was larger than thought and hot ice was not needed. It could still be a rocky super-Earth. It was later found to have a remarkably low levels of Methane and high levels of Carbon Monoxide for its 800K temperature. Possible explanations include Methane being changed into hydrocarbon polymers due to its star's ultraviolet radiation, CO being drafted upwards with winds, or observational defects. Later, due to lack of detection of chemical signatures through the backlit atmosphere, it was concluded that high altitude clouds, perhaps made of potassium chloride or zink sulphide dust, were blocking the detection. This could be the first detection of clouds of a Neptunian. An alternate theory is that the atmosphere is filled with heavy compounds, such as water, carbond dioxide, which would compress the atmosphere and make it difficult to detect. After detection of a huge comet-like tail of Hydrogen trailing and wrapping around its orbit led to the most recent theory that it lost its Hydrogen to uv radiation and was left with a Helium dominated atmosphere with plenty of CO instead of CH4. It's significant eccentricity suggests a possible neighboring planet. Planet c was announced to be the smallest known exoplanet (1.5 Earth's diameter), but was later retracted because variations in transit timing of the first planet did not occur and the proposed orbit would be unstable. It is still thought that a second planet of some kind is possible in the system. Candidate UCF-1.01 was detected by a student in the UCF's astronomy department using the Spitzer Space Telescope. It is about 2/3 Earth's diameter (smaller than all but one confirmed exoplanet), orbits around its star in 1.5 days, and at 1000F may be a lava world without an atmosphere. UCF-1.02 also may exist. Both are thought to be about 1/3 as massive as the Earth, but are too small to get their mass measured and thus too small to be confirmed with present technology.
- WASP-12 System (Sep 08) - 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..
- HD 80606 System (Jan 09) - Multiple star system (also known as Struve 1341) with a planet, which had a higher period (111 days) than any other known transiting planet and highest eccentricty (Halley's comet-like, epistellar distances to almost Earth-like distance) prior to the release of Kepler data. It is the nearest transiting Super Jupiter (4 MJ, radius slightly less than 1 RJ, 190ly). Its length of day is 36 hours. Discovered in 2001, but found to transit in 2009. Planet is the first one for which changes in weather have been observed. Potassium was detected from the high wind regions of the exosphere. In 2010 it was found to be only one of the two out of all 79 known transiting exoplanetary systems that could not support a habitable Earth-like planet, since its elongated orbit would destabilize any such planets. Planet thought to be in the process of becoming a Hot Jupiter. Observations suggested that energy transferred during closest approach to star would take 10 Billion Years to cause the orbit to circularize, meaning this tidal migration method may not be the preferred one to form hot jupiters.
- CoRoT-7 System (Feb 09) - A sunlike star about 500 light years away with two Hot Super Earths (and possibly a third), including the first detected transiting Super-Earth. It a diameter about twice that of the Earth. First exoplanet with evidence of a solid surface and does not possess a thick atmosphere. Because its star is active, its mass is somewhat uncertain (2.3 to 8.5 ME), which makes it unclear if the planet actually has a solid surface. Also the closest exoplanet to its star known and has the smallest orbit period (0.85 Earth Days). Likely the first Super-Io discovered (due to slight eccentricity) and the first gas giant remnant core found. Has temperature of 1000-1500C. Planet c is a larger Neptunian orbiting further away and does not transit.
- GJ 1214 System (Dec 09) -
- REDIRECT Gliese 1214 System
- CoRoT-Exo-9 System (Mar 10) - First temperate transiting Jupiter discovered. An 80% Jupiter Mass planet orbiting at a Mercury-like distance. Temperature could be between -20 to 160 C. Liquid water in the form of water clouds could exist. If its too hot, it could be cloudless. A moon covered by ice or liquid oceans could be around it, depending on its temperature.
- 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.
- Gliese 876 System - Ross 780 is also known as Gl 876 and the flare star IL Aquarii. Very nearby quadruple planet system and the first Red Dwarf found to have planets. The innermost planet (d, Hot Superterran, rocky-water) was the first found rocky planet around a normal star (the first true Super-Earth, at epistellar distances). The outer three planets c (Warm Saturnian), b (Warm Jovian), and e (Cold Neptunian) are in 1:2:4 (30d/60d/120d) resonance (the exoplanet resonance and first triple-resonant planets discovered). The outermost planet has a Mercury-like orbit. Planet b is second discovered by ELODIE after 51 Peg b and the second to have its mass exactly measured and the first to have done so by astrometry.
- Gliese 581 System - BD-11°3759 is better known as Gliese 581. Small nearby Red Dwarf with six planets in tight circular orbits. Several planets were announced in the habitable zone, but have since been retracted due to being due to sunspots rotating in view during it's 130 day rotation. E is the smallest known dopplar-detected exoplanet and a Super Mercury, b is a hot Neptunian, c is a super-Venus and the first detected in the HZ (initially heralded as habitable, but later thought too hot due to the greenhouse effect). G (1/4 stellar rotation) was the most controversial heralded as the first habitable Super-Earth and "Eyeball Earth", but was disproven. D (1/2 stellar rotation) was later thought to be an even more promising planet for life as it was big enough for a decent greenhouse effect even though it was at the outer edge of the habitable zone, was later thought to also not exist, but then its existence was re-affirmed. F was thought to be a cold super-Earth, but also disproven. The star is not very active. A massive Kuiper Belt was found, which may have been allowed to exist because the system lacks a Jovian class planet. A further out Neptunian may be responsible for the cometary collisions that produced the debris.
- 1RXS J160929.1-210524 System - Contains first exoplanet (full name 1RXS J160929.1-210524) imaged around a sun-like star, photographed in 2008 and confirmed to orbit star in 2010. The planet's very large distance from the star 330 AU causes problems for planetary formation theories. Some liken it to an unbalanced binary star system where one component gobbled up the vast majority of the dust. It has about 8 times Jupiter's mass and 11 times Neptune's distance. It could be a new type of sub-stellar object between a planet and a Brown Dwarf. First exoplanet to have its spectrum taken, which revealed evidence of water, carbon monoxide, and hydrogen. Its star is young enough (5 MY) so that the planet has not had enough time to cool (1,500 C) and thus detectable.
- HR 8799 System - Hot young star system 300 ly away which is the only imaged and wide multiplanetary system. The 30 MY old star is the only known Gamma Doradus variable that is also a Vega-like star. The innermost is e (14.5 AU, 10 MJ), followed by d (24 AU, 10 MJ), c (38 AU, 10 MJ), and b (68 AU, 7 MJ). Inside the inner planet's orbit is an asteroid belt, while outside of the outer planet is a cometary belt (including a clump at 1:2 resonance with the outermost planet), while further yet is a huge halo extending to 2000 AU. The outer three are planets are 2-2.5 times as far as Saturn, Uranus, and Neptune are respectively, but receive similar radiation. The large planets would likely pull the system apart, leading scientists to believe the inner three planets are probably locked in a 1:2:4 orbital resonance in order to maintain stability. An inner planet is at Saturn-to-Uranus-like distances and challenges planetary formation models. Fomalhaut is the only other system where interaction between planets and dust belts can be observed. They are near the upper limits of mass to be classified as planets and could be Brown Dwarves. Upper mass limits are determined by system stability models. All three planets were later found in archived Hubble images. The middle planet became the first to have its spectrum directly measured. The spectrum confused scientists and didn't fit current formation theories. They contain carbon monoxide and are depleted in methane, which suggests they were formed in part by absorbing comets in the system. The outermost planet b has unusually thick dust clouds. There is possibly a fifth undetected planet in an inner resonant orbit.
- GJ 758 System - Star with a giant planet or Brown Dwarf (M betw 10-40MJ) which has been directly photographed. Reguardless of its nature, it is the first and coolest substellar companion to a sunlike star ever photographed (333 C, about as hot as Mercury). It orbits at about Neptune's distance and is still in the contraction phase. A possible third companion may have been imaged, later observations should determine if it is bound to the system or merely an object in the background.
- Fomalhaut System - Fomalhaut is also known as Piscis Austrini, 24 Piscis Austrini, Gl 881, HD 216956, and HR 8728. A triple star, the second brightest star known to have exoplanets. Star A is a white main sequence star about twice the Sun's mass and somewhat less than twice its radius. It was originally thought to be about 200 million years old, but now thought to be 400 MYO, and will turn into a giant in about a billion years. Its dust disk is observed in unprecedented detail. It appears reminiscent of the "Eye of Sauron" from the Lord of the Rings films. A planet suspected of causing a sharp gap in the ring was suspected and imaged, becoming the first visually detected and the first planet since Neptune to be predicted prior to its discovery. The planet, Dagon, orbits about 115 AU and is between Neptune and 3x Jupiter's mass in an eccentric orbit. Planet b was shown to deviate slightly from its predicted path, stirring up some controversy about the planets' existence. The Hubble instrument that detected it is damaged and will not be fixed, making it unobservable for a time. Later analysis of old Hubble data confirmed its existence. Material surrounding the planet has been imaged, rather than the planet itself, which its discoverers admit takes it off the directly imaged list. The planet is hurdling outward from the star in a highly elongated path and will encounter the inner edge of the outer belt in 2032, where icy debris will smash into its atmosphere (unless its orbit is highly inclined). No heat has been detected from the planet, which suggests it is sub-Jovian in mass and could be as small as Pluto, though this could be explained by dissipation from surrounding dust. Evidence for another planet "slicing" through the dust disk was also found, and it may have been responsible for planet b's elliptical orbit. The shape of the ring was put into focus by ALMA, 140 AU out, 16 AU wide, and 1/7th AU thick, placing limits on proposed shepherding exoplanets and showing them to be quite small (a couple times larger than Mars), perhaps why they weren't detected visually. Mapping by ALMA was completed later on and shows the first "apocenter glow", where dust particles clump around slower moving and further out parts of their elliptical orbit. Some proposed inner planets via effects of debris disk could be better interpreted as gas produced effects. The ring is believed to be continuously replenished by cometary collisions occurring every day. An estimated 260 Billion to 83 Trillion comets could exist in it, equivalent to what is in the Sun's Oort Cloud. Star B, an orange dwarf 0.91 ly away has no known disk. Star C, a recently identified Red Dwarf member of the system, located extremely far from the primary (2.5 ly), was also found to have its own disk. Previous interactions may have tilted Star A's disk. The star is a part of the Castor Moving Group. One of the first 20 exoplanet systems allowed to be given common names by the IAU. The planet is named after a half fish Semitic god.
- Beta Pictoris System - Young massive star with the first discovered circumstellar disk and the source of most interstellar meteorites in the Solar System. Comet crystals were found to be similar composition as those in Solar System. The first exo-comet was discovered in this system in 1983 and is the only star known with a detected comet known to also have a planet. Hundreds of comets detected by transit, of which on average of 6 transits occur in a 30 minute spetra, have been placed into two groups. One family (Population D for "deep" absorption lines) were older comets depleted of their volatiles and trapped in mean motion resonance with planet b or another undiscovered one. The other is fresher (Population S for "shallow"), emit more dust, follow similar orbits, and may have been formed after the breakup of a larger object. Contains the youngest known exo-planet, which shows that Jupiter-like planets can form much quicker than previously believed. It is the closest-in exoplanet photographed and is at 8 AU and 7-11 Jupiter Masses and orbits in 20 years. This planet was first hinted at by studying dust disks in 2003 and first photographed in 2003, but it was not confirmed and was lost. It was imaged again in 2008, and became the first imaged exoplanet confirmed to move around its star in 2010. It has an effective temperature of 1,100 to 1,700C, showing that it is still warm and has retained much of its heat from its formation. Evidence of a planetary transit in 1981 was found in record. It was originally thought that a second planet must have caused a tilt in one of the disks, but now it known that the first planet is. Models show that it could create waves and spirals in the disk. Some data suggests the planet is unusually wide, perhaps evidence of a ring system around it. The planet is traveling through a relatively dust-free gap in the debris disk, and thought to be clearing it. The planet is losing momentum as it travels through the debris disk. A large belt of carbon monoxide 50-160 AU concentrated at 85 AU has been observed, possibly caused by collision of comets. A Saturn sized planet interior to the belt that is not currently detectable due to being edge on in the disk could be shepherding it. It is possible that diamond-planets are forming in the disk. A cubesat could target this star in search of a second planet using the transit method since the system is edge-on. Principle member of the Beta Pictoris Moving Group.
Dust Disk SystemsEdit
- Vega System - Vega is also known as Alpha Lyrae, HR 7001, HD 172167, and Gl 721. It is the fifth brightest star in the night sky the second brightest star visible from the Northern hemisphere, and brightest star in the Northern Summer. It is part of the Summer Triangle. It was the first star to be photographed in 1850. It is a slightly bluish star (A0) with about 2.15 times the sun's mass and 2.7 its diameter. It was at first estimated to be about 200 Million Years old, but now thought to be closer to 700. It was found to be rotating so fast that the equator bulges significantly (23%) and is cooler at its poles. Nearby star with one of the first detected circumstellar disks. The star is pointed nearly pole-on from the Earth, so it is ideal for the observation of dust disks. There have been many studies suggesting planets are responsible for features found in the disk. Two bright "clumps" of dust were identified and thought to be due to the gravitational effects of an eccentric planet's orbit. It was surmised that this disk was caused by a collision between Pluto sized objects. A distinct asteroid belt and kuiper belt at distance scales that dwarf our Solar Systems was found to exist, which suggest outer planets clearing out the space in between. These planets cannot be detected at the present, but could be detected by the James Webb Space Telescope. One of 5 PICTURE-C targets selected for sub-orbital coronograph observation.
- Tau Ceti System - Tau Ceti is also known as HD 10700, HR 509, and Gl 71. The nearest single G-class yellow dwarf to the sun, somewhat smaller than the Sun. A popular science fiction subject and one of two targets of SETI-forerunner Project Ozma in the 1960s. Despite being somewhat older than the sun, it has an extensive asteroid and/or comet field 10-50 AU, with the bulk between 35 and 50 AU. It has about ten times as much material as the Sun. This would make life difficult. It is a metal deficient star, so it is thought less likely to host rocky planets. Traditional dopplar spectrometry has ruled out any large Jupiter sized planets at Jupiter like distances or closer in, which was thought to be good for any potentially habitable planets. Five candidate rocky super Earth planets were detected though using a new method of planetary detection. This method made predictions of the stellar "noise" activity that might obscure detection of a planet based on the long history of dopplar measurements done on this system. Deviations from this prediction pointed towards the existence of planets. Confirmation using more established methods is needed. These planets are labeled b through f as you go outward, span 0.1 AU to 1.35 AU, and get larger the further you go out (at least 2 ME to 6.6 ME). The outermost two are near the habitable zone and were originally hailed as possibly being the nearest and smallest known habitable planets. More recent modeling indicates they are not actually habitable though. Planet e is probably too close to the star and only in the HZ if generous assumptions are made. Planet f has probably only been in the habitable zone for about a billion years as a result of its star becoming hotter, which might make biosigns difficult to detect from Earth, considering it took 2 BY for biosigns to become detectable around the Earth. Since the star has a higher magnesium to silicon ratio than the Sun, these planets compositions could be quite different that the Solar System's. The lower mantles could be dominated with ferropericlase, which is not very viscious, which may make the rocks of the mantle flow easier than on Earth, affecting volcanism and tectonics. One of 5 PICTURE-C targets selected for sub-orbital coronograph observation.
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