The report, to be published in the Feb. 15 issue of the journal Science, describes the series of observations that began March 28, 2006, when a collaboration known as Optical Gravitational Microlensing Equipment (OGLE) detected a signal, possibly due to a planet in microlensing event OGLE-2006-BLG-109, that the researchers had discovered and announced two days earlier.
After the OGLE group announced this possible detection of a planetary system via e-mail, other astronomers from the Microlensing Follow-Up Network (MicroFUN), Microlensing Observations in Astrophysics (MOA) and Probing Lensing Anomalies NETwork (PLANET) collaborations also began intensive, round-the-clock observations of this event. The combined data from these four groups revealed a series of brightness variations over the ensuing 11 days that indicated that two planets orbit a star half the mass of the sun located 5,000 light years from Earth. This star, called OGLE-2006-BLG-109L, and its planets were discovered using a technique known as gravitational microlensing.
Early calculations by the report’s lead author, Scott Gaudi of Ohio State University, and the MicroFUN group indicated that most of the telltale brightness variations were due to a planet with a mass similar to that of Saturn, but that there was a brief additional brightening observed from Israel and Chile that could only be explained by an additional planet with nearly the mass of Jupiter. However, Gaudi’s calculations did not provide a perfect fit to the data and involved several approximations.
Subsequently, Bennett performed more sophisticated calculations in his office at Notre Dame using his own advanced computer program that included an important additional feature: the orbital motion of the Saturn-mass planet.
“Even though we observed the micolensing effect of the Saturn for less than 0.3 percent of its orbit, the observations simply could not be explained without accounting for the orbit,” Bennett said.
Critical assistance with these calculations was provided by Sergei Nikolaev at Lawrence Livermore National Laboratory, who devoted much supercomputer time to the calculations.
The result was one of the most complicated calculations of a star-planet system using the gravitational microlensing method.
Gravitational microlensing takes advantage of the fact that light is bent as the rays pass close to a massive object, like a star. The gravity from the mass of the intervening object, or lens star, warps surrounding space and acts like a giant magnifying glass. As predicted by Albert Einstein and later confirmed, this phenomena causes an apparent brightening of the light from the background “source” star. The effect is seen only if the astronomer’s telescope lies in almost perfect alignment with the source star and the lens star. Astronomers are then able to detect planets orbiting the lens star if the light from the background star also is warped by the planets.
The discovery of the double planet system was a triumph for astronomers who use this method, which is of such high sensitivity that it can detect planets similar to those in our own solar system, with the exception of Mercury.
“These planets could not have been detected without any other technique,” Bennett said.
“The light curve of this event revealed an unprecedented amount of information about the planetary host star and the planets,” he continued.
The effect of the orbital motion of the Earth can be detected in the light curve, and this reveals that the mass of the host star is half the mass of the sun. This mass estimate was confirmed by subsequent observations of the planetary host star with the Keck telescope.
The light curve also reveals the orbital motion of the Saturn-mass planet during the 11 days when the planetary signal was visible.
To date, only 25 multiple planet systems have been observed. A majority are very dissimilar to our solar system and that of OGLE-2006-BLG-109L.
The Jupiter- and Saturn-sized planets orbiting OGLE-2006-BLG-109L are only the fifth and sixth planets that have been detected using the gravitational lensing method. Gaudi and Bennett conclude that if the OGLE-2006-BLG-109L planetary system is typical, then it is possible that they would have similar planets as our own solar system.
William Gilroy | EurekAlert!
Scientists create fully electronic 2-dimensional spin transistors
18.09.2019 | University of Groningen
The magic wavelength of cadmium
16.09.2019 | University of Tokyo
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.
The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.
At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.
Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...
Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.
This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.
Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.
If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...
10.09.2019 | Event News
04.09.2019 | Event News
29.08.2019 | Event News
18.09.2019 | Physics and Astronomy
18.09.2019 | Life Sciences
18.09.2019 | Life Sciences