Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Hunt for Distant Planets Intensifies

20.02.2013
When astronomers discovered planet GJ 1214b circling a star more than 47 light-years from Earth in 2009, their data presented two possibilities. Either it was a mini-Neptune shrouded in a thick atmosphere of hydrogen and helium, or it was a water world nearly three times the size of Earth.

Along came Jacob Bean, now an assistant professor in astronomy & astrophysics at the University of Chicago, who used a new method called multi-object spectroscopy to analyze the planet’s atmosphere from large, ground-based telescopes. Aided by technology, Bean and his colleagues are surmounting the challenge of inferring the atmospheric composition of planets that were invisible to humans just a few years ago.

“We’re trying to distinguish whether it’s like the gas giants we know about, or something fundamentally different from what we’ve seen in our solar system — an atmosphere predominantly composed of water,” Bean said.

The search for exoplanets - planets beyond our own solar system - has taken off over the last decade, and is now a growing component of UChicago’s research agenda in astronomy. One estimate published in January calculated that our Milky Way galaxy alone contains at least 17 billion Earth-sized planets, with a vast potential for life-sustaining worlds. Pursuing the exoplanet search via complementary methods are Bean and Daniel Fabrycky, another assistant professor in astronomy & astrophysics.

Bean has received a 60-orbit allocation on the Hubble Space Telescope to continue his observations on GJ 1214b, a sign of the work’s importance. Previous HST studies of planetary atmospheres encompassed 10 to 20 orbits. Bean will use a technique called transmission spectroscopy to measure the chemical composition of the planet’s atmosphere with unprecedented precision.

A big prize

A definitive assessment of the planet’s atmosphere could lead to a larger prize: learning how to detect potential signs of alien life on a cosmically distant Earth twin. The atmospheric signature of life on an exoplanet presumably would contain some mixture of oxygen and various other gases.

Planetary scientists are conducting theoretical studies to narrow the range of possibilities.

“It’s interesting to note that all the instruments astronomers have used to study exoplanet atmospheres so far were never designed for that,” Bean said. “We’re using them in very unusual ways. We do what we can with what we have.”

But now Bean aims to build a system that is perfectly suited and well optimized to study exoplanet atmospheres, including that of GJ 1214b.

“The current data suggest an atmosphere predominately composed of water, but it’s not a definitive result yet,” Bean said. “There could be even more exotic scenarios possible that we’re not able to rule out.”

If GJ 1214b is a water world, “It would be very different than anything in our own solar system,” said Harvard University astronomy Professor David Charbonneau, whose team discovered the planet.

Deep questions

The search taps into some of modern science’s deepest questions: Are humans alone in the cosmos, and is our life-sustaining world unique? One of the earliest writers to speculate about exoplanets was the Italian philosopher and scientist Giordano Bruno, who was burned at the stake in 1600 for espousing beliefs that the Catholic Church deemed heretical.

In one prescient passage, Bruno wrote, “In space there are countless constellations, suns and planets; we see only the suns because they give light; the planets remain invisible, for they are small and dark. There are also numberless earths circling around their suns, no worse and no less than this globe of ours.”

Discoveries of new exoplanets have flowed like oil from a gushing wellhead in recent years. The number has topped 850 and continues to climb.

Starting in the 1990s, exoplanet hunters initially were only able to find giant, Jupiter-like gas planets because they were bigger and thus easier to find. “They were closer to their stars than Jupiter is from the sun, so we nicknamed them ‘hot Jupiters,’” Charbonneau said.

But in recent years, scientists began pursuing a new, more interesting goal: find planets that are more Earthlike. One major push along that front was the $600-million Kepler mission, launched in 2009. This mission, encompassing a 100-member science team, is conducting a survey of planets orbiting other sun-like stars.

“Kepler is on the cusp of finding small planets in the habitable zone around both sun-like and small stars,” Fabrycky said. “This is the goal of the mission, and it’s almost there.”

New research frontiers at UChicago

A Kepler research veteran, Fabrycky began his UChicago faculty appointment last October. Fabrycky precisely measures the timing of transits, the mini eclipses that planets cause as they pass in front of their stars. Timing inconsistencies in the transits often result from the gravitational influence of other planets.

So far Kepler has 105 confirmed planet discoveries to its credit, and has identified 2,740 planet candidates. As a postdoctoral scientist at the University of California, Santa Cruz, two years ago, Fabrycky was a member of a team that discovered six planets orbiting a single star called Kepler-11. “Kepler-11 is hanging on — for the moment — as the one with the most number of planet signals” among exoplanetary systems, Fabrycky said.

Bean and his colleagues have made the best observations of planetary atmospheres so far using the Hubble Telescope, the Spitzer Space Telescope, and, in Chile, the Very Large Telescope array and the twin Magellan Telescopes. But the planned Giant Magellan Telescope, of which UChicago is a founding partner, and the forthcoming James Webb Space Telescope should eclipse the capabilities of today’s observatories when they go into service late this decade.

The new telescopes will be able to do the same sort of exoplanetary atmospheric studies underway now, “but actually do it for the smaller planets that might even be habitable,” Charbonneau said.

Steve Koppes | Newswise
Further information:
http://www.uchicago.edu

More articles from Physics and Astronomy:

nachricht Physicists precisely measure interaction between atoms and carbon surfaces
29.05.2015 | University of Washington

nachricht How comets were assembled
29.05.2015 | Universität Bern

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: Lasers are the key to mastering challenges in lightweight construction

Many joining and cutting processes are possible only with lasers. New technologies make it possible to manufacture metal components with hollow structures that are significantly lighter and yet just as stable as solid components. In addition, lasers can be used to combine various lightweight construction materials and steels with each other. The Fraunhofer Institute for Laser Technology ILT in Aachen is presenting a range of such solutions at the LASER World of Photonics trade fair from June 22 to 25, 2015 in Munich, Germany, (Hall A3, Stand 121).

Lightweight construction materials are popular: aluminum is used in the bodywork of cars, for example, and aircraft fuselages already consist in large part of...

Im Focus: Wie Solarzellen helfen, Knochenbrüche zu finden

FAU-Forscher verwenden neues Material für Röntgendetektoren

Nicht um Sonnenlicht geht es ihnen, sondern um Röntgenstrahlen: Wissenschaftler der Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) haben zusammen mit...

Im Focus: Festkörper-Photonik ermöglicht extrem kurzwellige UV-Strahlung

Mit ultrakurzen Laserpulsen haben Wissenschaftler aus dem Labor für Attosekundenphysik in dünnen dielektrischen Schichten EUV-Strahlung erzeugt und die zugrunde liegenden Mechanismen untersucht.

Das Jahr 1961, die Erfindung des Lasers lag erst kurz zurück, markierte den Beginn der nichtlinearen Optik und Photonik. Denn erstmals war es Wissenschaftlern...

Im Focus: Solid-state photonics goes extreme ultraviolet

Using ultrashort laser pulses, scientists in Max Planck Institute of Quantum Optics have demonstrated the emission of extreme ultraviolet radiation from thin dielectric films and have investigated the underlying mechanisms.

In 1961, only shortly after the invention of the first laser, scientists exposed silicon dioxide crystals (also known as quartz) to an intense ruby laser to...

Im Focus: Szenario 2050: Ein Wurmloch in Big Apple

Andy ist Physiker und wohnt in New York. Obwohl er schon seit fünf Jahren im Big Apple arbeitet, ist ihm die Stadt immer noch fremd – zu laut, zu hektisch, zu schmutzig. Wie soll das in Zukunft weitergehen? Die Antwort erfährt er prompt – und am eigenen Leib.

„New York – die Stadt, die niemals schläft.“ Lieber Franky Boy Sinatra, ich bin ganz bei Dir. Schon 1977 hattest du mit deinem Song ganz recht. Einen wichtigen...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

Cannabis – eine andauernde Kontroverse

29.05.2015 | Veranstaltungen

Frauen können nicht alles haben - Männer aber schon?!

29.05.2015 | Veranstaltungen

13. Koblenzer eLearning Tage

28.05.2015 | Veranstaltungen

 
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

Superelastische Metalle ohne Ermüdung: Kieler Forschende entwickeln neues intelligentes Material

29.05.2015 | Materialwissenschaften

Innovative Therapie verbessert Lebensqualität bei Morbus Parkinson

29.05.2015 | Medizin Gesundheit

Wie Kometen entstanden sind

29.05.2015 | Physik Astronomie