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Exoplanetary Scratchpad

[SysBP Img]

The multiplicity of exoplanet host starsEdit

Spectroscopic confirmation of the companions GJ3021B and HD27442B, one new planet host triple-star system, and global statistics
From http://fr.arxiv.org/abs/astro-ph/0703795 abstract:
We present new results from our ongoing multiplicity study of exoplanet host stars and present a list of 29 confirmed planet host multiple-star systems. Furthermore, we discuss the properties of these stellar systems and compare the properties of exoplanets detected in these systems with those of planets orbiting single stars.

Main StudiesEdit

  • Gliese 3021 System - Multiple star system with a planet.
  • HD 27442 System - (aka Epsilon Reticuli) A cloudless blue jovian around an orange sub-giant star. This was the first exoplanet discovered beyond 0.2 AU that had a circular orbit.
  • HD 40979 System - Multiple star system with a planet.

Exoplanet host stars in multiple-star systemsEdit

Class-1 Systems (a, e assumed)Edit

  • 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.
  • 83 Leo System - (aka 83 Leonis) Multiple star system with a planet.
  • Gliese 3021 System - Multiple star system with a planet.
  • 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.
  • Gliese 86 System - Contains the first exoplanet discovered by CORALIE of the Geneva southern extrasolar planet search programme. A cloudless blue heavy jupiter and a white dwarf around an orange star.
  • HD 109749 System - Multiple star system with a planet.
  • HD 114729 System - Multiple star system with a planet.
  • HD 114762 System - Multiple star system containing the first discovered extrasolar planet, though not the first confirmed one. This planet was also called Latham's Planet. It could be a Brown Dwarf, though a Super Jupiter seems more likely.
  • HD 142 System - Multiple star system with a planet.
  • HD 142022 System - Multiple star system with a planet.
  • HD 16141 System - A yellow subgiant star around which the smaller of the first 2 Saturnians discovered (HD 46375 b was the other one) is in a Mercury-like orbit.
  • HD 195019 System - A cloudless blue jovian around an yellow dwarf star.
  • HD 196050 System - Multiple star system with a planet.
  • HD 213240 System - Multiple star system with a planet.
  • HD 222582 System - Multiple star system with a planet.
  • HD 27442 System - (aka Epsilon Reticuli) A cloudless blue jovian around an orange sub-giant star. This was the first exoplanet discovered beyond 0.2 AU that had a circular orbit.
  • HD 46375 System - An orange subgiant around which the larger of the first two Saturnians discovered (79 Ceti b was the other one) orbits, which was the first "Epistellar Saturn" discovered.
  • HD 75289 System - A cloudy Hot Jupiter around an yellow dwarf star.
  • HD 80606 System - 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.
  • HD 89744 System - Contains a highly eccentric planet which was recently studied to determine what other planets could exist in the system.
  • 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.
  • HD 40979 System - Multiple star system with a planet.
  • HD 401004 System - Multiple star system with a planet.
  • HD 178911 System - A cloudless blue jovian around one of the two yellow giant star in a binary system.

Class-2 Systems (a, e known)Edit

  • Gamma Cephei System - Jovian and red dwarf around an orange sub-giant.
  • HD 19994 System - (aka 94 Ceti) A yellow water cloud Jovian around a hot yellow dwarf star. Has a low C/O ratio like the solar system.
  • Tau Bootis System - 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 188753 System - First triple star system found to have a planet.
  • 16 Cygni System - A hierarchical triple star system. Has one of the first highly eccentric Jovians discovered around the "outer" star B. Recent calculations show that a short period planet could exist around the same star, but none up to as large as Neptune could exist elsewhere. Kepler has performed astroseismology on stars A and B.


10 Most Intriguing Stars of 2007Edit

Planet Quest asked number of leading planet hunters to name their most intriguing stars for 2007 and posted the results.
http://planetquest.jpl.nasa.gov/intriguing_launch_page.cfm

  • 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.
  • 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.
  • Pollux System - Pollux is also known as Beta Geminorum, HR 2990, HD 62509, and Gl 286. It was originally called Polydeuces by the Greeks, after the immortal twin. The brightest star in Geminorum, which suggests it may have used to be the second brightest four centuries ago, and is the 17th brightest star in the sky. It is an orange-red giant star (K0 III) 1.7 times the Sun's mass and 8.8 its diameter and 724 MYO. It is the nearest (34 ly) giant star to the Sun. Its spectra has been used as a stable anchor point since 1943. It has one of the weakest measured magnetic field of any star. Planet Thestias was confirmed in 2006 that was first suspected in 1993. It orbits 1.64 AU in a circular path and is at least 2.3 times as massive as Jupiter. This is much nearer than the present habitable zone, which is centered at 5.7 AU. This is the brightest star in the sky known to have a planet. One of the first 20 exoplanet systems allowed to be given common names by the IAU. Named after the mother of Pollux, Leda. However, Leda is already taken as a moon of Jupiter, so a name derived from her father is used, which is sometimes used to refer to her or her sister..
  • HAT-P-1 System - 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.
  • 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.
  • Epsilon Indi System - Epsilon Indi is the also known as HR 8387, Gl 845, and HD 209100. Second nearest single sunlike star to the Sun. Orange dwarf with a binary brown dwarf orbiting it. The smaller of the two is the closest thing to an "extrasolar moon" found so far. The constellation "Indus" first appeared in 1603 in the Uranometria. Epsilon Indi appeared as one of the Indian's arrows in Bode's 1801 atlas, the Uranographia. The star's high proper motion was first discovered by Gill in 1882, which was improved upon by Shapley in 1923. During 1960, the star was observed for radio signals, but none was found. In 1972, it was searched for ultraviolet laser signals. It leads a Carnegie list of stars most likely to have an earth-like planet. The star's age has been controversial, at first thought to be older than the sun, then younger, then even older than originally thought, all based on studies regarding the brown dwarf's nature and the rotation rate of the star.
  • HD 209458 System - 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.
  • HD 189733 System - 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.
  • 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 69830 System - First planetary system found that does not have a Jupiter-sized planet around a normal star (K0 spectrum). Contains 3 Neptunians and the first discovered asteroid belt that is like the size and age as the Sun's. The debris from this belt that was detected was from the breakup of an asteroid, is 20 times as massive as our own, and would cause zodiacal lights 1000 times brighter than we see from Earth. The smallest and outermost planet may be a 10 ME super Earth, is within the habitable zone, and is an inner shepherd for the asteroid belt. Halo 3 features a fictitious moon around this planet.
  • 40 Eridani System - Kied is also known as 40 Eridani, Omicron 2 Eri, and Gl 166. Triple star which is Gene Roddenberry's favored location for Spock's home planet of Vulcan. Consists of an Orange Dwarf primary A (also called HD 26965 and HR 1325) with a flare star Red Dwarf C (also called DY Eridani) orbiting 50 AU away, and a much further White Dwarf B at 600 AU. The white star would appear two orders of magnitude brighter than Venus does from any planets in AC, so it would be visible in the daylight. While no planet has been discovered in this system yet, it has been selected as a target for the SIM Planet quest when launched in 2015 for signs of a habitable planet. The White Dwarf is by far the easiest White Dwarf to observe, as it is brighter than the closer Van Manaan's Star and is not swamped by the light of a bright primary like those found in the Sirius or Procyon systems.

Dynamical and Observational Constraints on Additional Planets in Highly Eccentric Planetary SystemsEdit

http://fr.arxiv.org/abs/0706.1962
Robert A. Wittenmyer, Michael Endl, William D. Cochran, Harold F. Levison
(Submitted on 13 Jun 2007)

Abstract: Long time coverage and high radial velocity precision have allowed for the discovery of additional objects in known planetary systems. Many of the extrasolar planets detected have highly eccentric orbits, which raises the question of how likely those systems are to host additional planets. We investigate six systems which contain a very eccentric (e>0.6) planet: HD 3651, HD 37605, HD 45350, HD 80606, HD 89744, and 16 Cyg B. We present updated radial-velocity observations and orbital solutions, search for additional planets, and perform test particle simulations to find regions of dynamical stability. The dynamical simulations show that short-period planets could exist in the HD 45350 and 16 Cyg B systems, and we use the observational data to set tight detection limits, which rule out additional planets down to a few Neptune masses in the HD 3651, HD 45350, and 16 Cyg B systems.

  • HD 3651 System - 54 Piscium is a nearby orange dwarf star also known as HR 166, Gl 27, Hip 3093, HD 3651. Has an eccentric planet about the mass of Saturn orbiting at Mercury-like distances. A recently discovered faint distant T type brown dwarf 476 AU away was found to be the cause of this eccentricity, which was directly imaged.
  • HD 37605 System - Contains the first exoplanet discovered by the Hobby-Eberly Telescope (HET), which was the third most eccentric planet found, ranging from Hot Jupiter distance to Mercury-like distance.
  • HD 45350 System - Contains a highly eccentric planet which was recently studied to determine what other planets could exist in the system.
  • HD 80606 System - Contains a highly eccentric planet which was recently studied to determine what other planets could exist in the system.
  • HD 89744 System - Contains a highly eccentric planet which was recently studied to determine what other planets could exist in the system.
  • 16 Cygni System - A hierarchical triple star system. Has one of the first highly eccentric Jovians discovered around the "outer" star B. Recent calculations show that a short period planet could exist around the same star, but none up to as large as Neptune could exist elsewhere. Kepler has performed astroseismology on stars A and B.

28 Planets Announced in May 2007 AASEdit

List of planets announced at the Astronomical Astronomical Society media briefing May 28 2007. This list includes all the planets discovered by the California and Carnegie Planet Search team and the Anglo-Australian Planet Search team for the past year. A total of 28 new exoplanets is the largest amount announced at one time, adding 12% to the number of known planets since the previous year to make the total known 236.

  • HD 86081 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 187123 System - Template loop detected: Template:HD 187123 System
  • HD 14810 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 185269 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 33283 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 17156 System - Star system containing a planet discovered by dopplar spectrometry method and later found by amateurs to transit. At the time, it smashed the records for the furthest transiting planet (period of 21 d, 0.0523 to 0.26 AU) and most eccentric orbit. Its orbit was found to be well aligned with the rotation of its star. Its size has been measured better with the Hubble Telescope (3.8 MJ). A second, unconfirmed planet has also been proposed for this system.
  • HD 224693 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 11964 System - Sunlike star with two eccentric gas giants detected in 2005. The outermost one was retracted but then re-confirmed as one of the 28 planets announced at the May 2007 AAS media briefing. The inner most has half the mass of Saturn and is too hot for clouds. The outer one is cool and likely dominated by white water clouds. A middle planet may also exist.
  • HD 107148 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 73526 System - System with two large orbit-crossing Jovians locked in 1:2 resonance that would span the inner solar system to the asteroid belt. The second planet was one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 75898 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 231701 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 175541 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 99109 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 192699 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 210702 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 5319 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 159868 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 164922 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 170469 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 23127 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • Gliese 849 System - BD-05°5715 is best known as Gliese 849 and also known as LHS 517. Nearby red dwarf star system in Aquarius with a planet. Contains the first long period exoplanet found around a red dwarf star using dopplar spectrometry. Also only the second Jupiter mass planet around a star less massive than half the Sun. Also the first confirmed Jupiter-sized planet at Neptune-like temperatures. There is evidense for a second planet.
  • HD 11506 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 66428 System - System that includes one of the 28 planets announced at the May 2007 AAS media briefing.
  • HD 154345 System - Closest solar system analog to date. Contains a Jupiter like planet at Jupiter like distances 4.18 AU in a circular orbit with no known giant planets orbiting inside it. The star is dimmer than the Sun and habitable region at Venus like distances.

Related ArticlesEdit

http://exoplanets.org/aasjune07s/pr_280507.htm
http://www.spacetoday.net/articles_bycategory.php?cid=12
http://www.upi.com/NewsTrack/Science/2007/05/29/astronomers_find_new_planets/4706/ http://www.astronomy.com/asy/default.aspx?c=a&id=5602
http://www.berkeley.edu/news/media/releases/2007/05/29_exoplanets.shtml
http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/05/29/MNG9CQ336T1.DTL&type=science
http://news.bbc.co.uk/2/hi/science/nature/6699893.stm
http://www.space.com/scienceastronomy/070528_exoplanet_report.html
http://www.reuters.com/article/scienceNews/idUSN2826900020070528
http://www.latimes.com/news/science/la-na-exoplanets29may29,1,1274185.story?coll=la-news-science&ctrack=1&cset=true http://www.guardian.co.uk/space/article/0,,2089929,00.html

Five New Multicomponent Planetary Systems (Jan 2005)Edit

Abstract
Steven S. Vogt , R. Paul Butler , Geoffrey W. Marcy , Debra A. Fischer ,Gregory W. Henry , Greg Laughlin ,2 Jason T. Wright, and John A. Johnson

ABSTRACT

We report Doppler measurements for six nearby G- and K-type main-sequence stars that show multiple low-mass companions, at least one of which has planetary mass. One system has three planets, the fourth triple-planet system known around a normal star, and another has an extremely low minimum mass of 18 M⊕. HD 128311 (K0 V) has two planets (one previously known) with minimum masses (M sin i) of 2.18MJ and 3.21MJ and orbital periods of 1.26 and 2.54 yr, suggesting a possible 2 : 1 resonance. For HD 108874 (G5 V), the velocities reveal two planets (one previously known) having minimum masses and periods of (M sin ib = 1.36MJ, Pb = 1.08 yr) and (M sin ic = 1.02MJ, Pc = 4.4 yr). HD 50499 (G1 V) has a planet with P = 6.8 yr and M sin i = 1.7MJ, and the velocity residuals exhibit a trend of -4.8 m s-1 yr-1, indicating a more distant companion with P > 10 yr and minimum mass of 2MJ. HD 37124 (G4 IV–V) has three planets, one having M sin i = 0.61MJ and P = 154.5 days, as previously known. We find two plausible triple-planet models that fit the data, both having a second planet near P = 840 days, with the more likely model having its third planet in a 6 yr orbit and the other one in a 29 day orbit. For HD 190360, we confirm the planet having P = 7.9 yr and M sin i = 1.5MJ as found by the Geneva team, but we find a distinctly noncircular orbit with e = 0.36 ± 0.03, rendering this not an analog of Jupiter as had been reported. Our velocities also reveal a second planet with P = 17.1 days and M sin i = 18.1 M⊕. HD 217107 (G8 IV) has a previously known "hot Jupiter" with M sin i = 1.4MJ and P = 7.13 days, and we confirm its high eccentricity, e = 0.13. The velocity residuals reveal an outer companion in an eccentric orbit, having minimum mass of M sin i > 2MJ, eccentricity e ∼ 0.5, and a period P > 8 yr, implying a semimajor axis a > 4 AU and providing an opportunity for direct detection. We have obtained high-precision photometry of five of the six planetary host stars with three of the automated telescopes at Fairborn Observatory. We can rule out significant brightness variations in phase with the radial velocities in most cases, thus supporting planetary reflex motion as the cause of the velocity variations. Transits are ruled out to very shallow limits for HD 217107 and are also shown to be unlikely for the prospective inner planets of the HD 37124 and HD 108874 systems. HD 128311 is photometrically variable with an amplitude of 0.03 mag and a period of 11.53 days, which is much shorter than the orbital periods of its two planetary companions. This rotation period explains the origin of periodic velocity residuals to the two-planet model of this star. All of the planetary systems here would be further constrained with astrometry by the Space Interferometry Mission.

  • 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.
  • HD 108874 System - System with two Jovians that could have bands of white water clouds. The inner planet is in a circular orbit and enjoy's Earth-like heat. Its second planet, which was announced with four other new multiplanet systems in 2005, is in an eccentric orbit that would span our solar system's inner asteroid belt.
  • HD 217107 System - Contains the first discovered moderately eccentric Hot Jupiter. Its outer planet was suspected when the inner one was discovered due to its eccentricity (0.13) and confirmed with four other new multiplanet systems in 2005. The Outer planet c is highly eccentric and skirts the outer edge of the habitable zone.
  • HD 50499 System - Star system with a cold eccentric water-cloud jovian and an unconfirmed outer planet which was discussed when the Carnegie team announced 5 new multiplanet system components in 2005.
  • 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.
  • HD 190360 System - (aka Gliese 777) 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.

Spitzer Sees Dust Around 6 Stars With PlanetsEdit

(Dec 2004)
For the first time, dust has been detected around systems that have confirmed planets. Six such systems were announced together.

  • HD 117176 System - One of the six extrasolar systems known to have planets to be first shown to also have a dust disk by Spitzer.
  • 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.
  • HD 50554 System - One of the six extrasolar systems known to have planets to be first shown to also have a dust disk by Spitzer.
  • HD 52265 System - Sunlike star 90 ly away in Monoceros with a planet. Star is 1.2 the Sun's radius, 1.3 its mass, and 2.5 BY old. The star is an ideal object of study for the interactions between stars and planets. One of the six extrasolar systems known to have planets to be first shown to also have a dust disk by Spitzer. Planet independently discovered by CORALIE and Carnegie teams and is at least a 1.09 MJ Jovian in a hot eccentric orbit. By analyzing sonic vibrations, oscillations in brightness, through astroseismology, the exact internal spin rate (12 days) and orientation of the star has been computed. Assuming the planet orbits along the star's equator, it's mass can be inferred to be 1.85 Jupiter's, calming some suspicions that it may be a brown dwarf.
  • HD 82943 System - Yellow dwarf with two large orbit-crossing Jovians locked in 1:2 orbital resonance that would span the inner solar system, which were disccovered by the Swiss team by 2001. The planets have nearly identical mass (1.8 MJ). Shown to have a dust disk by Spitzer.
  • 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.

Related ArticlesEdit

http://www.nasa.gov/home/hqnews/2004/dec/HQ_04390_hubble_spitzer.html
http://www.space.com/scienceastronomy/planet_formation_041209.html
http://www.astronomy.com/asy/default.aspx?c=a&id=2648
http://www.newscientist.com/article.ns?id=dn6780
http://skytonight.com/news/3309801.html?page=1&c=y
http://www.signonsandiego.com/news/science/20041209-1438-ca-buildingplanets.html

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