Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

First Search in Stellar Graveyard Yields Two Possible Planets

14.01.2005


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."


The team earlier had detected three candidate planets that they found to be background objects after taking a second image. "If the two remaining candidates also are background objects, that discovery would indicate the frequency of planets around white dwarfs is quite small, though a larger sample of white dwarfs must be studied to more accurately gauge their frequency," Sigurdsson explains.

Because it is nearly impossible with current telescopes to see a planet around a nearby star as bright as the Sun, Sigurdsson’s team searched around near-by white dwarfs, whose dim glow is much less likely to obscure a companion planet. A white dwarf is up to thousands of times dimmer than the Sun and the contrast between it and a planet several times Jupiter’s mass is about a factor of ten thousand less. "If we could find such a planet, then we can use the evidence it provides, like forensic investigators, to tell what the planetary system was like when the star was alive," Debes says.

The research is part of an intense race to take the first "photograph" of an extrasolar planet. Astronomers seek to compare the picture of an extrasolar planet with various theories about how such planets should look. This comparison will help reveal how the solar system formed and how frequent life may be in the Milky Way galaxy. Further discoveries are expected when larger and more sensitive telescopes are built that can better detect Jupiter-size planets.

This research was supported by the Penn State Astrobiology Research Center and the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #9834.

Barbara K. Kennedy | EurekAlert!
Further information:
http://www.psu.edu

More articles from Physics and Astronomy:

nachricht NASA's SDO sees partial eclipse in space
29.05.2017 | NASA/Goddard Space Flight Center

nachricht Strathclyde-led research develops world's highest gain high-power laser amplifier
29.05.2017 | University of Strathclyde

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>