The powerful vision of NASA¹s Hubble Space Telescope has allowed astronomers to study for the first time the layer-cake structure of the atmosphere of a planet orbiting another star. Hubble discovered a dense upper layer of hot hydrogen gas where the super-hot planet¹s atmosphere is bleeding off into space.
The planet, designated HD 209458b, is unlike any world in our solar system. It orbits so close to its star and gets so hot that its gas is streaming into space, making the planet appear to have a comet-like tail. This new research reveals the layer in the planet¹s upper atmosphere where the gas becomes so heated it escapes like steam rising from a boiler.
³The layer we studied is actually a transition zone where the temperature skyrockets from about 1,340 degrees Fahrenheit (1,000 Kelvin) to about 25,540 degrees (15,000 Kelvin), which is hotter than the Sun,² said Gilda Ballester of the University of Arizona in Tucson, leader of the research team. ³With this detection we see the details of how a planet loses its atmosphere.²
The findings by Ballester, David K. Sing, of the University of Arizona and the Institut d¹Astrophysique de Paris, and Floyd Herbert of the University of Arizona will appear Feb. 1 in a letter to the journal Nature.
Intense ultraviolet radiation from the host star heats the gas in the upper atmosphere, inflating the atmosphere like a balloon. The gas is so hot that it moves very fast and escapes the planet¹s gravitational pull at a rate of 10,000 tons a second, more than three times the rate of water flowing over Niagara Falls. The planet, however, will not wither away any time soon. Astronomers estimate its lifetime is more than 5 billion years.
The scorched planet is a big puffy version of Jupiter. In fact, it is called a ³hot Jupiter,² a large gaseous planet orbiting very close to its parent star. Jupiter might even look like HD 209458b if it were close to the Sun, Ballester said.
The planet completes an orbit around its star every 3.5 days. It orbits 4.7 million miles from its host, 20 times closer than the Earth is to the Sun. By comparison, Mercury, the closest planet to our Sun, is 10 times farther away from the Sun than HD 209458b is from its star. Unlike HD 209458b, Mercury is a small ball of iron with a rocky crust.
³This planet¹s extreme atmosphere could yield insights into the atmospheres of other hot Jupiters,² Ballester said.
Although HD 209458b does not have a twin in our solar system, it has plenty of relatives beyond our solar system. About 10 to 15 percent of the more than 200 known extrasolar planets are hot Jupiters. A recent Hubble survey netted 16 hot Jupiter candidates in the central region of our Milky Way Galaxy, suggesting that there may be billions of these gas-giant star huggers in our galaxy.
HD 209458b is one of the most intensely studied extrasolar planets because it is one of the few known alien worlds that can be seen passing in front of, or transiting, its star, causing the star to dim slightly. In fact, the gas giant is the first such alien world discovered to transit its star. HD 209458b is 150 light-years from Earth in the constellation Pegasus.
The transits allow astronomers to analyze the structure and chemical makeup of the gas giant¹s atmosphere by sampling the starlight that passes through the planet¹s atmosphere. The effect is similar to finding fingerprints on a window by watching how sunlight filters through the glass.
Previous Hubble observations revealed oxygen, carbon, and sodium in the planet¹s atmosphere, as well as a huge hydrogen upper atmopshere with a comet-like tail. These landmark studies provided the first detection of the chemical makeup of an extrasolar planet¹s atmosphere.
Additional observations by NASA¹s Spitzer Space Telescope captured the infrared glow from the planet's hot atmosphere.
The new study by Ballester and her team is based on an analysis of archival observations made in 2003 with Hubble's Space Telescope Imaging Spectrograph by David Charbonneau of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Ballester's team analyzed spectra from hot hydrogen atoms in the planet's upper atmosphere, a region not studied by Charbonneau's group.
Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Information Technology
05.12.2016 | Earth Sciences