Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Planet hunters no longer blinded by the light

18.10.2010
UA astronomers have developed a way to see faint planets previously hidden in their star's glare. The new mode enables scientists to search for planets closer to the star than has been previously possible

Using new optics technology developed at the University of Arizona's Steward Observatory, an international team of astronomers has obtained images of a planet on a much closer orbit around its parent star than any other extrasolar planet previously found.

The discovery, published online in Astrophysical Journal Letters, is a result of an international collaboration among the Steward Observatory, the Swiss Federal Institute of Technology Zurich, the European Southern Observatory, Leiden University in the Netherlands and Germany's Max-Planck-Institute for Astronomy.

Installed on the European Southern Observatory's Very Large Telescope, or VLT, atop Paranal Mountain in Chile, the new technology enabled an international team of astronomers to confirm the existence and orbital movement of Beta Pictoris b, a planet about seven to 10 times the mass of Jupiter, around its parent star, Beta Pictoris, 63 light years away.

At the core of the system is a small piece of glass with a highly complex pattern inscribed into its surface. Called an Apodizing Phase Plate, or APP, the device blocks out the starlight in a very defined way, allowing planets to show up in the image whose signals were previously drowned out by the star's glare.

"This technique opens new doors in planet discovery," said Phil Hinz, director of the UA's Center for Astronomical Adaptive Optics at Steward Observatory. "Until now, we only were able to look at the outer planets in a solar system, in the range of Neptune's orbit and beyond. Now we can see planets on orbits much closer to their parent star."

In other words, if alien astronomers in another solar system were studying our solar system using the technology previously available for direct imaging detection, all they would see would be Uranus and Neptune. The inner planets, Mercury, Venus, Earth, Mars and Saturn, simply wouldn't show up in their telescope images.

To put the power of the new optics system in perspective: Neptune's mean distance from the sun is about 2.8 billion million miles, or 30 Astronomical Units, or AUs. One AU is defined as the mean distance between the sun and the Earth.

The newly imaged planet, Beta Pictoris b, orbits its star at about seven AUs, a distance where things get especially interesting, according to Hinz, "because that's where we believe the bulk of the planetary mass to be in most solar systems. Between five and 10 AUs."

While planet hunters have used a variety of indirect methods to detect the "footprints" of extrasolar planets – planets outside our solar system – for example the slight gravitational wobble an orbiting planet induces in its parent star, very few of them have been directly observed.

According to Hinz, the growing zoo of extrasolar planets discovered to date – mostly super-massive gas giants on wide orbits – represents a biased sample because their size and distance to their parent star makes them easier to detect.

"You could say we started out by looking at oddball solar systems out there. The technique we developed allows us to search for lower-mass gas giants about the size of Jupiter, which are more representative of what is out there."

He added: "For the first time, we can search around bright, nearby stars such as Alpha Centauri, to see if they have gas giants."

The breakthrough, which may allow observers to even block out starlight completely with further refinements, was made possible through highly complex mathematical modeling.

"Basically, we are canceling out the starlight halo that otherwise would drown out the light signal of the planet," said Johanan (John) Codona, a senior research scientist at the UA's Steward Observatory who developed the theory behind the technique, which he calls phase-apodization coronagraphy.

"If you're trying to find something that is thousands or a million times fainter than the star, dealing with the halo is a big challenge."

To detect the faint light signals from extrasolar planets, astronomers rely on coronagraphs to block out the bright disk of a star, much like the moon shielding the sun during an eclipse, allowing fainter, nearby objects to show up.

Using his own unconventional mathematical approach, Codona found a complex pattern of wavefront ripples, which, if present in the starlight entering the telescope, would cause the halo part to cancel out but leave the star image itself intact. The Steward Observatory team used a machined piece of infrared optical glass about the size and shape of a cough drop to introduce the ripples. Placed in the optical path of the telescope, the APP device steals a small portion of the starlight and diffracts it into the star's halo, canceling it out.

"It's a similar effect to what you would see if you were diving in the ocean and looked at the sun from below the surface," explained Sascha Quanz from the Swiss Federal Institute of Technology's Institute for Astonomy, the lead author of the study. "The waves on the surface bend the light rays and cause the sky and clouds to appear quite different. Our optic works in a similar way."

In order to block out glare from a star, conventional coronagraphs have to be precisely lined up and are highly susceptible to disturbance. A soft night breeze vibrating the telescope might be all it takes to ruin the image. The APP, on the other hand, requires no aiming and works equally well on any stars or locations in the image.

"Our system doesn't care about those kinds of disturbances," Codona said. "It makes observing dramatically easier and much more efficient."

In the development of APP, Codona was joined by Matt Kenworthy (now at Leiden Observatory in the Netherlands). Hinz, who is a member of the instrument upgrade team for the VLT, played a key role in the technique's implementation on the 6.5 Meter Telescope on Mount Hopkins in Southeastern Arizona.

Former UA astronomy professor Michael Meyer, now at the Swiss Federal Institute of Technology Zurich, where he led the group implementing the technology on the VLT, pointed out that APP is likely to advance areas of research in addition to the hunt for extrasolar planets.

"It will be exciting to see how astronomers will use the new technology on the VLT, since it lends itself to other faint structures around young stars and quasars, too."

Daniel Stolte | EurekAlert!
Further information:
http://www.arizona.edu

More articles from Physics and Astronomy:

nachricht Space radiation won't stop NASA's human exploration
18.10.2017 | NASA/Johnson Space Center

nachricht Study shows how water could have flowed on 'cold and icy' ancient Mars
18.10.2017 | Brown University

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>