Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 


Hunt for Distant Planets Intensifies

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:

More articles from Physics and Astronomy:

nachricht Graphene microphone outperforms traditional nickel and offers ultrasonic reach
27.11.2015 | Institute of Physics

nachricht Tracking down the 'missing' carbon from the Martian atmosphere
25.11.2015 | California Institute of Technology

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: Tübinger Forscher entdecken neue Zelltypen im Gehirn

Untersuchung im Neocortex von Mäusen - Zusammenarbeit mit Wissenschaftlern aus Houston

Wissenschaftler aus Tübingen und Houston haben zahlreiche neue Zelltypen im Gehirn identifiziert. Im Neocortex von erwachsenen Mäusen führten sie erstmals eine...

Im Focus: Klimawandel: Forscher weisen dramatische Veränderung in den 1980er Jahren nach

Ende der 1980er Jahre erlebte die Erde eine dramatische Klimaveränderung. Sie umfasste die Tiefen der Ozeane ebenso wie die obere Atmosphäre und reichte vom Nord- bis zum Südpol. Ausgelöst durch den Ausbruch des Vulkans El Chichón in Mexico 1982 und verstärkt durch menschliches Handeln folgte daraus die größte Temperaturverschiebung der letzten 1.000 Jahre. Erstmals nachgewiesen hat dies ein internationales Forscherteam um Prof. Philip C. Reid von der Plymouth University und der Sir Alister Hardy Foundation for Ocean Science (UK). Die Ergebnisse wurden kürzlich in der Fachzeitschrift „Global Change Biology“ veröffentlicht.

Abrupte Klimaveränderungen haben oft dramatische Folgen für unseren Planeten. Dennoch sind sie in ihrer Art, ihrem Ausmaß und in ihrer Wirkungsweise meist nur...

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaik – vom Labor an die Fassade

Fraunhofer ISE demonstriert neue Zell- und Modultechnologien an der Außenfassade eines Laborgebäudes

Das Fraunhofer-Institut für Solare Energiesysteme ISE hat die Außenfassade eines seiner Laborgebäude mit 70 Photovoltaik-Modulen ausgerüstet. Die Module...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Alle Focus-News des Innovations-reports >>>



im innovations-report
in Kooperation mit academics

Bürger treffen Experten: Gespräch zu Chancen und Risiken der Nanotechnologie am 30.11.2015

27.11.2015 | Veranstaltungen

Arbeit in Sozialen Dienstleistungen - Welche Zukunft hat die Branche?

27.11.2015 | Veranstaltungen

Konzepte nutzergerechter Fahrerarbeitsplatzgestaltung

26.11.2015 | Veranstaltungen

Weitere VideoLinks >>>
Aktuelle Beiträge

Künstliche Herzklappe nach dem Vorbild der Natur

27.11.2015 | Förderungen Preise

Siemens liefert 126 Megawatt Onshore-Windleistung nach Schottland

27.11.2015 | Unternehmensmeldung

Hauptkläranlage Wien wird mit Siemens zum Ökokraftwerk

27.11.2015 | Energie und Elektrotechnik