News About Planet Finding 2000-2005
July 7, 2005 | Amateur Detects New Transiting Exoplanet. By Robert Naeye, Sky & Telescope magazine. Excerpt: A day before an international team announced a new transiting planet orbiting the star HD 149026 on June 30th, California amateur astronomer Ron Bissinger [Kepler EPO Advisory board] detected a partial transit of that planet. ... This new find, HD 149026b, is now the third transiting exoplanet detected by amateurs. "Ron's data are of excellent quality," says professional astronomer Gregory P. Laughlin (University of California, Santa Cruz), who is a member of the team that discovered the new planet. Laughlin has also helped organize the Transitsearch.org network to enable amateurs like Bissinger to detect such events. ...advance notice enabled Bissinger to observe HD 149026 on the night of June 29th, when a transit was predicted. ...Because the planet has a 2.877-day orbital period, he was able to observe partial transits again on the nights of July 2nd and July 5th. "Unfortunately I could not get a single complete transit due to the late onset of darkness, so I pieced the segments together," says Bissinger. ... "That is truly beautiful work he is doing, and it is contributing to the precision of the radius measurement for the planet," adds veteran exoplanet hunter Geoffrey W. Marcy (University of California, Berkeley [and Kepler scientist]), who is also a member of the discovery team. ...Last year, Bissinger and other amateurs in the Transitsearch.org network recorded anomalies in the light curve of TrES-1 transits. ...Hubble Space Telescope transit observations made last year by Timothy Brown (National Center for Atmospheric Research [and Kepler scientist]) and his colleagues also show anomalies in the light curve, strongly suggesting that the amateur data were not plagued by systematic errors. ...
13 July 2005. Triple Sunset: Planet Discovered in 3-Star System. By Michael Schirber, space.com. A newly discovered planet has bountiful sunshine, with not one, not two, but three suns glowing in its sky. It is the first extrasolar planet found in a system with three stars. How a planet was born amidst these competing gravitational forces will be a challenge for planet formation theories. "The environment in which this planet exists is quite spectacular," said Maciej Konacki from the California Institute of Technology. "With three suns, the sky view must be out of this world -- literally and figuratively." The triple-star system, HD 188753, is located 149 light-years away in the constellation Cygnus. The primary star is like our Sun, weighing 1.06 solar masses. The other two stars form a tightly bound pair, which is separated from the primary by approximately the Sun-Saturn distance.
June 30, 2005. NASA RELEASE: 05-169. NASA Researchers Discover Planet with Largest Solid Core. NASA researchers recently discovered the largest solid core ever found in an extrasolar planet, and their discovery confirms a planet formation theory. "For theorists, the discovery of a planet with such a large core is as important as the discovery of the first extrasolar planet around the star 51 Pegasi in 1995," said Shigeru Ida, theorist from the Tokyo Institute of Technology, Japan. ... "None of our models predicted that nature could make a planet like the one we are studying," said Bun'ei Sato, consortium member and postdoctoral fellow at Okayama Astrophysical Observatory, Japan. ...This planet also passes in front of its star and dims the starlight. "When that happens, we are able to calculate the physical size of the planet, whether it has a solid core, and even what its atmosphere is like," said Debra Fischer. She is consortium team leader and professor of astronomy at San Francisco State University, Calif. The planet, orbiting the sun-like star HD 149026, is roughly equal in mass to Saturn, but it is significantly smaller in diameter. It takes just 2.87 days to circle its star, and the upper atmosphere temperature is approximately 2,000 degrees Fahrenheit. Modeling of the planet's structure shows it has a solid core approximately 70 times Earth's mass. This is the first observational evidence that proves the "core accretion" theory about how planets are formed. Scientists have two competing but viable theories about planet formation. In the "gravitational instability" theory, planets form during a rapid collapse of a dense cloud. With the "core accretion" theory, planets start as small rock-ice cores that grow as they gravitationally acquire additional mass. Scientists believe the large, rocky core of this planet could not have formed by cloud collapse. They think it must have grown a core first, and then acquired gas. "This is a confirmation of the core accretion theory for planet formation and evidence that planets of this kind should exist in abundance," said Greg Henry, an astronomer at Tennessee State University, Nashville. He detected the dimming of the star by the planet with his robotic telescopes at Fairborn Observatory in Mount Hopkins, Arizona. Support for this research came from NASA, the National Astronomical Observatory of Japan and the National Science Foundation. A paper about this discovery was accepted for publication in the Astrophysical Journal. The paper, supporting materials and illustrations are available on the Internet at: http://tauceti.sfsu.edu/n2k/
June 13, 2005.KECK FINDS MOST EARTH-LIKE PLANET YET FOUND OUTSIDE THE SOLAR SYSTEM [Mauna Kea] Data obtained at the W. M. Keck Observatory has resulted in the discovery of the most Earth-like world to ever be discovered -- but it's not likely to hold that record for long. The discovery centers around the smallest extrasolar planet to ever be discovered and the first in a new series of rocky, terrestrial planets orbiting stars other than our sun. It took more than 150 observations of this star to obtain the necessary data for this result. The newly-discovered planet orbits a red dwarf star named Gliese 876, which is just one-third the mass of the Sun, and is located about 15 light years from Earth. This new planet is a very unusual world -- more than seven times the mass of the Earth, orbiting its star in just two days at a distance of just .021 astronomical units, or less than one-tenth that of Mercury's orbit inside our own solar system. Theoretical astronomer Jack Lissauer of NASA's Ames Research Center [and Kepler Science Team], and post-doctoral researcher Eugenio J. Rivera of UCO/Lick have been analyzing Keck data on the Gliese 876 system to model the unusual motions of the two known planets, and three years ago got an inkling that there might be a smaller, third planet orbiting the star. In fact, if they hadn't taken account of the resonant interaction between the two known planets, they never would have seen the third planet. "We had a model for the two planets interacting with one another, but when we looked at the difference between the two-planet model and the actual data, we found a signature that could be interpreted as a third planet," Lissauer said. See also NSF press release .
March 23, 2005. Alien Planets Show Themselves for First Time. NY Times.
By DENNIS OVERBYE. Astronomers said yesterday that they, or at least their telescopes, had laid eyes for the first time on planets beyond the solar system. Using the NASA Spitzer Space Telescope and careful timing, teams studying two planets were able to distinguish the glow of the planets' infrared radiation from the overwhelming glare of their parent stars. ...Dr. Geoffrey W. Marcy, a planet hunter at the University of California, Berkeley, called the results "the stuff of history books" and added, "With this result, we are closer to understanding our own human roots, chemically, among the stars. Dr. Alan P. Boss, a planetary theorist at the Carnegie Institution of Washington, said in an e-mail message that the discoveries showed "that we are well along the way to combining astronomy and biology into the new science of astrobiology, with the ultimate goal being to search for life beyond Earth." ... the astronomers were able to use the special geometry of these planetary systems to tease out the faint light of each planet from its parent's glare, comparing measurements made while the planet and star were both visible and while the planet was hidden behind the star. ...When the astronomers put on their "infrared goggles," as Dr. Charbonneau put it, the planets popped into view. The Spitzer telescope registered a dip in light of about a quarter of 1 percent in each case when the planet went behind its star....
March 22, 2005. NASA RELEASE: 05-082 NASA's Spitzer Marks Beginning of New Age of Planetary Science. NASA's Spitzer Space Telescope captured the light, for the first time, from two known planets orbiting stars other than our sun. The findings mark the beginning of a new age in planetary science, in which extrasolar planets can be directly measured and compared. ... "Spitzer has provided us with a powerful new tool for learning about the temperatures, atmospheres and orbits of planets hundreds of light-years from Earth," said Dr. Drake Deming of NASA's Goddard Space Flight Center (GSFC), Greenbelt, Md. Deming is lead author of a new study on one of the planets. "It's fantastic," said Dr. David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass., lead author of a separate study on a different planet. "We've been hunting for this light for almost 10 years, ever since extrasolar planets were first discovered." In the new studies, Spitzer directly observed the warm infrared glows of two previously detected "hot Jupiter" planets, designated HD 209458b and TrES-1. Hot Jupiters are extrasolar gas giants that zip closely around their parent stars. From their toasty orbits, they soak up ample starlight and shine brightly in infrared wavelengths. To distinguish this planet glow from the fiery hot stars, the astronomers used a simple trick. First, they used Spitzer to collect the total infrared light from both the stars and planets. Then, when the planets dipped behind the stars as part of their regular orbit, the astronomers measured the infrared light coming from just the stars. This pinpointed exactly how much infrared light belonged to the planets. "In visible light, the glare of the star completely overwhelms the glimmer of light reflected by the planet," Charbonneau said. "In infrared, the star-planet contrast is more favorable because the planet emits its own light." ...Spitzer is ideally suited for studying extrasolar planets, known to transit stars the size of our sun, out to distances of 500 light-years. Of the seven known transiting planets, only the two mentioned here meet those criteria. See also Release at Spitzer Space Telescope newsroom.
October 29, 2004 Detection of Possible Anomalies in the Transit Lightcurve of Exoplanet TrES-1b Using a Distributed Observer Network Author: Ron Bissinger (1) Contributors: Dr. Greg Laughlin (2), Dr. Tim Castellano(3), Bruce Gary(4), Joe Garlitz(5), Tonny Vanmunster (6), Pertti Pääkkönen(7), Tommi Itkonen(7), Kent Richardson(8), Jon Holtzman(9). ABSTRACT: Through a collaboration by amateur and professional astronomers functioning as a distributed observers network, apparent anomalies have been identified in the transit lightcurves of exoplanet TrES-1b made by different observers at multiple times. A detailed visual analysis of the lightcurves reveal brightenings of 3 to 5 mmag before ingress and after egress as well as short term fluctuations of < 3mmag for durations of approximately 10 minutes. The anomalies appear to be symmetrical around the transit midpoint. A rigorous bootstrap Monte Carlo analysis indicates a high probability that the lightcurve brightenings before ingress and after egress are statistically significant. Full article in PDF (PDF, 178 KB) is also at Tonny Vanmunster's Exoplanet Page at CBA Belgium Observatory. There is an article "Amateurs Catch Exoplanet Transit" in Sky & Telescope magazine, jan 2005, pp. 132-134.
Jul 2, 2004 -- Asteroids Make Tau Ceti Lethal ... nearby star, Tau Ceti, is surrounded by 10 times as many asteroids and comets as our own Solar System. Even if there are planets orbiting Tau Ceti, they would be unlikely to support life because of the frequent and devastating impacts by these objects. This discovery will help astronomers narrow down their search when looking for distant worlds that may support life; ones which have a small number of comets and asteroids.
May 2004. APlanet's Magnetic Footprint. News Note from Sky & Telescope magazine, p. 24. ASTRONOMERS HAVE FOUND an extrasolar planet with a magnetic personality. The planet orbits HD 179949, ... in Sagittarius that's a little hotter and brighter than the Sun (spectral type F8). After studying the star during three observing runs in 2001-02, a Canadian team led by Evgenya Shkolnik (University of British Columbia) identified a strange hot spot in the star's upper atmosphere (chromosphere) that revolves around the star every 3.093 days exactly the same period as the planet's orbital period. In contrast, the star itself rotates once every 8 to 10 days....It has kept in perfect lockstep with the planet for more than 100 orbits as it marches around the star slightly ahead of the planet. "This is the first glimpse of a magnetic field of an extrasolar planet," said Shkolnik at an American Astronomical Society press conference in January. Theorists Steven Saar (Harvard-Smithsonian Center for Astrophysics) and Manfred Cuntz and Zdzislaw Musielak (both at the University of Texas, Arlington) predicted in 2000 that an interaction between a planet's and a star's magnetic fields could produce just such a hot spot.... Shkolnik's team used a high resolution spectrograph on the 3.6-meter Canada-France-Hawaii Telescope to identify two spectral features of ionized calcium flagging the planet's hot "footprint" on the star....In the latest model from Saar and his colleagues, stellar magnetic-field lines stretch and pile up in front of the planet's magnetosphere .... This pile-up discharges its energy in sporadic outbursts similar to solar flares. The flares accelerate charged particles, which follow stellar magnetic-field lines down onto the star's chromosphere, producing the hot spot. "Since the star's magnetic field is swept back by the star's own rotation, this model explains the fact that the hot spot actually leads the planet," says Saar...."There is nothing faxfetched at all about this," says independent expert Gibor Basri (University of California, Berkeley). All the large planets in the solar system have substantial magnetic fields. Giant exoplanets probably have strong fields as well. - R. N.
May 2004. Blowin' in the Exoplanet Wind. Sky & Telescope News Notes. FIRST IT WAS SODIUM, then it was hydrogen, now it's oxygen and carbon. Astronomers are detecting more and more atmospheric constituents of HD 209458b, a gas-giant planet 150 light-years away that orbits its star at only 12 percent of Mercury's average distance from the Sun. HD 209458b is the only known case of an exoplanet that transits across the face of a bright star. This chance alignment gives astronomers a chance to detect absorption features in the star's spectrum that result from starlight skimming through the planet's outer atmosphere. By carefully comparing the star's spectrum when the planet is and is not in transit, astronomers had previously discovered sodium (S&T: March 2002, page 22) and a vast, comet-like trail of escaping hydrogen (S&T: June 2003, page 20). In an upcoming issue of Astrophysical Journal Letters, an international team led by Alfred Vidal-Madjar (Astrophysics Institute of Paris, CNRS) now reports finding atomic oxygen and carbon in the escaping cloud. Observing at ultraviolet wavelengths with the Hubble Space Telescope's imaging spectrograph, Vidal-Madjar's team detected weak absorption lines of oxygen and carbon.... The elements were in a bloated atmosphere nearly three times larger than the planet, covering 8 to 10 percent of the star's disk (the planet itself eclipses only 1.5 percent). The star, 7th-magnitude FM 209458 in Pegasus, blowtorches the planet's uppermost atmosphere to a temperature of 10,0000 Kelvin, causing at least 10,000 tons of hydrogen per second to escape.... The planet appears to shed gas at such a high rate that it could lose more than 10 percent of its mass during its lifetime. This, in turn, suggests the existence of a class of whittled-down planets - gas giants close to their stars that were stripped of their outer envelopes, leaving rock-iron cores with only a few Earth masses. The next generation of planet-transit searches could identify such bodies. - R. N.
16 Dec 2003. T-7XMEI and ST-9XEI Observing Capabilities, Research and TDI Imaging - ST-7-9I Camera Applications by Alan Holmes (PDF)
2003 June 5. Front Page of USA Today: Is there another Earth out there?
November 26, 2002. PlanetQuest 'Spotlight' on VPL Gets CNN's Attention
2002 Oct 24. Amateur Astronomers Joining Hunt for Planets http://www.csmonitor.com/2002/1024/p11s02-stss.html
2002 June 13. Planets Rule the News: Navigator supports June 13 NASA SSU and Planet-Finder Marcy: http://www.cbsnews.com/stories/20026/13/tech/main512150.shtml
May 14, 2002. Telescopes Mission: Search for Earthlike Planets, CNN.com
23-27 October 2000 DPS Pasadena Meeting 2000, Session 26. Future Missions Posters [26.08] Eclipse - A Discovery Mission for Direct Imaging Investigations of Nearby Planetary Systems - by J. Trauger (JPL), K. Stapelfeldt (JPL), D. Backman (F & M Col.), R.A. Brown (STScI), R. Burg (JHU), A. Burrows (U. Arizona), C. Ftaclas (Mich.~Tech.~U.), J.D. Kirkpatrick (IPAC), S. Kulkarni (Caltech), J. Lunine (U. Arizona), G. Marcy (UC Berkeley), D. Redding (JPL), R. Sahai (JPL), B. Woodgate (GSFC) — Eclipse is a proposed Discovery mission to perform the first sensitive imaging study of nearby planetary systems and their evolutionary stages from formation as young stellar objects to their demise as planetary nebulae. During a three-year science mission, Eclipse will directly detect and characterize jovian planets, zodiacal dust structures, and brown dwarf companions associated with stars in the solar neighborhood; survey the protoplanetary disks of nearby molecular clouds; and study the dissolution of planetary systems in the winds of dying stars. The mission will provide fundamental information on the presence and evolution of planetary systems and our Sun's nearest neighbors in the galaxy. Eclipse is a high-contrast optical telescope for exoplanetary astronomy. Eclipse brings together a 1.8 meter space telescope configured for low optical scattering, a coronagraphic camera for control of diffracted light, and precision active optics for control of scattered light, in an integrated system designed from the outset for high-contrast astronomy. Compared to instruments that will be available to HST, Eclipse reduces diffracted and scattered starlight at one arcsecond separation by an additional three orders of magnitude.