Now, a team led by Jacob Bean (Harvard-Smithsonian Center for Astrophysics) has made the first measurements of GJ 1214b's atmosphere. However, the measurements raise as many questions about the planet's atmospheric composition as they answer.
"This is the first super-Earth known to have an atmosphere," said Bean. "But even with these new measurements we can't say yet what that atmosphere is made of. This world is being very shy and veiling its true nature from us."
A super-Earth is a planet up to three times the size of Earth and weighing one to ten times as much. (GJ 1214b is 2.7 times the size of Earth and 6.5 times as massive.) They are likely to be mostly solid (some combination of rock or ices), unlike the hundreds of Jupiter-sized gas giants found to date around distant stars.
Researchers suggested three atmospheric possibilities for GJ 1214b. The most intriguing was a thick blanket of steam vaporized by the nearby star. (This option led to the nickname "waterworld," although it's too hot for an ocean.) The second option was a mini-Neptune with a rocky core surrounded by ices and a hydrogen/helium atmosphere. The third model has no equivalent in our solar system - a big, rocky world with a soupy mix of gases (mainly hydrogen) recently emitted by volcanoes.
To study the planet's atmosphere, the team observed it when it crossed in front of its star. During such transits, the star's light filters through the atmosphere. Gases absorb the starlight at particular wavelengths, or colors, leaving behind a chemical fingerprint detectable from Earth. Similar observations have found gases like hydrogen and sodium vapor in the atmospheres of distant "hot Jupiters."
"This is the first super-Earth to have its atmosphere analyzed. We've reached a real milestone on the road toward characterizing these worlds," stated Bean.
Commenting on the work, Harvard astronomer David Charbonneau, who is not involved in the recent study but led the team that discovered GJ 1214b, agreed. "In less than 10 years, we've gone from studying the atmospheres of alien worlds like Jupiter, to Neptunes, to super-Earths. Earth-sized worlds are next, although they'll be the most difficult."
The spectrum of GJ 1214b proved to be featureless, which ruled out a cloud-free atmosphere composed primarily of hydrogen. If the atmosphere of GJ 1214b has abundant hydrogen, then it must be cloaked by a thick blanket of clouds (like Venus) or haze (like Saturn's moon Titan). A dense, steamy atmosphere also fits the data.
"It would have to be very dense - about one-fifth water vapor by volume," explained Bean. "Compared to our Earth, with an atmosphere that's four-fifths nitrogen and one-fifth oxygen with only a touch of water vapor."
The team examined GJ 1214b in the near-infrared region of the spectrum (780 - 1000 nanometers) using the ground-based Very Large Telescope at Paranal Observatory in Chile. Additional observations in the mid- or far-infrared might finally answer the question: Is the atmosphere of GJ 1214b steamy or gassy?
"A lot of people are putting this planet under a microscope," said Bean. "In the next year, we should have some solid answers about what it's truly like."
Christine Pulliam | EurekAlert!
An international team of physicists a coherent amplification effect in laser excited dielectrics
25.09.2017 | Universität Kassel
Highest-energy cosmic rays have extragalactic origin
25.09.2017 | CNRS
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy