Astronomers are announcing today the first results of a search for extrasolar planets and brown dwarfs in an unlikely place--the stellar graveyard. The report, titled "Searching for Extrasolar Planets in the Stellar Graveyard," is being presented at the American Astronomical Society meeting in San Diego, California, by John Debes, a graduate student at Penn State; Steinn Sigurdsson, associate professor of astronomy and astrophysics at Penn State University; Bruce Woodgate, of the NASA Goddard Space Flight Center, and their collaborators. These results are particularly interesting because they answer some questions about the presence of planets around stars that are more massive than the Sun.
Shown here is one of the 20 target white dwarfs of our survey. The white dwarf is at the center of the image and has been masked out. North is up and east is to the left. Nearby to the east is a candidate companion (circled), which if associated would be a massive planet or low mass brown dwarf. It needs further observations to confirm or refute its association with the white dwarf.
The research team found two candidate planets in its survey of 20 dead stars--white dwarfs at distances between 24 and 220 lightyears--with three telescopes: the Near-Infrared Camera and Multi-Object Spectrograph on the Hubble Space Telescope, the Canada France Hawaii 3.6-meter (150-inch) Telescope, and the Gemini North 8-meter (300-inch) Telescope. White dwarfs are small, dense, Earth-sized objects that are the leftover corpse of a star that has run out of enough fuel to shine brightly but was once as massive as--or several times more massive than--the Sun. The researchers had calculated that they should be able to detect planets with a mass 10 times that of Jupiter if any were present around most of the white dwarfs, and as small as five times the mass of Jupiter around a few of them, but they detected only two promising candidate planets among the 20 white dwarfs they studied. "You have to be careful with a candidate planet because it often is just a background object," says Sigurdsson. "Since all of our candidates are incredibly faint, we cannot obtain spectra for them to identify whether they are a planet, a brown dwarf, or a background galaxy."
To determine whether the candidates are planets, the Sigurdsson team now plans to take two snapshots of each over a period of several months to a year. "Each target white dwarf moves across the sky about 1/3000 of the diameter of the full moon every year, whereas background objects do not appear to move at all," Debes explains, "so if a candidate moves with the white dwarf that would show that the two are physically associated and the candidate is a planet in orbit around the white dwarf."
Barbara K. Kennedy | EurekAlert!
Pulses of electrons manipulate nanomagnets and store information
21.07.2017 | American Institute of Physics
Vortex photons from electrons in circular motion
21.07.2017 | National Institutes of Natural Sciences
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
21.07.2017 | Earth Sciences
21.07.2017 | Power and Electrical Engineering
21.07.2017 | Physics and Astronomy