The small, cool M-dwarf star TRAPPIST-1 and its seven worlds. New research from the University of Washington speculates the possible…
Not all stars are like the sun, so not all planetary systems can be studied with the same expectations. New research from a Washington-led team of astronomers provides updated climate models for the seven planets around the Star TRAPPIST-1
The work can also help astronomers to more effectively study planets around stars, unlike our sun and better use of limited and expensive resources in the James Webb Space Telescope, which is now expected to start in 2021.
“We model unknown atmospheres, not only assuming that the things we see in the solar system will look the same around another star, “said Andrew Lincowski, UW doctoral student and author of a paper published November 1 in the Astrophysical Journal . “We conducted this research to show what these different types of atmosphere can look like.”
The team found that because of an extremely warm and bright early star phase, all seven of the star’s worlds have evolved like Venus, with some early oceans they can have evaporated and left dense, uninviting atmospheres. However, a planet, TRAPPIST-1e, can be an earthly marine activity worth studying, as previous research has also indicated.
TRAPPIST-1, 39 light years or about 235 miles away is about as small as a star can be and still be a star. A relatively cool “M dwarf” star – the most common type in the universe – it has about 9 percent of the sun’s mass and about 12 percent its radius. TRAPPIST-1 has a radius just a little bigger than the planet Jupiter, but it is much larger in mass.
All seven of the TRAPPIST-1 planets are about the size of the earth and three of them – planets labeled e, f and g – are believed to be in their habitable zone that surrounds a star where a rocky planet could have floating water on its surface , giving life a chance. TRAPPIST-1 d rides into the inhabited zone, while it is farther out, TRAPPIST-1 h, just over the outer edge of the zone.
“This is a whole series of planets that can give us insight into the development of planets, especially around a star that is very different from ours, with other light coming from it,” said Lincowski. “It’s just a gold mine. “
Previous articles have modeled TRAPPIST-1 worlds, meant Lincowski, but he and this research group” tried to make the most rigorous physical modeling we could in terms of radiation and chemistry – tried to get the physics and chemistry as right as possible. ” “
The team’s radiation and chemical models create spectral or wavelength signatures for each possible atmospheric gas, enabling observers to better predict where to look for such gases in the exoplanet atmospheres. Lincowski said when traces of gases are actually detected by Web telescope or others, one day, “astronomers will use the observed shocks and fan in spectra to determine which gases are present – and compare it to act as ours to say something about the planet’s composition, environment and perhaps its evolutionary history. “
He said people usually think that a planet lives near stars like the sun.” But M-dwarf stars are very different, so you really have to think about the chemical effects on the atmosphere and how that chemistry affects the climate. “
Combining terrestrial climate modeling with photochemistry models, researchers simulated environmental states for each of the TRAPPIST-1 worlds.
Their modeling indicates that:
Lincowski said that in reality, any or all of the TRAPPIST-1 planets may be Venus-like, with some water or ocean burned for a long time. He explained that as the water evaporates from the surface of a planet, ultraviolet light is broken from the star together by the water molecules, releasing hydrogen, which is the easiest element and can escape a gravity of the planet. This could lead to a lot of oxygen, which can remain in the atmosphere and irreversibly remove water from the planet. Such a planet may have a thick oxygen atmosphere – but not one that is produced by life, and differs from what has yet to be observed.
“It may be possible if these planets had more water than in the beginning than the Earth, Venus or Mars,” he said. “If the planet TRAPPIST-1 e did not lose its entire water during this phase, today it can be a world of water completely covered by a global ocean. In this case it may have a climate similar to the Earth.”
Lincowski said that This research was done more with an eye on climate development than judging the planet’s habitat. He plans future research focusing more directly on the modeling of water planets and their chances of life.
“Before we knew about this planetary system, it was estimated that it was much more difficult to estimate atmospheric detectability of Earth’s planets,” author Jacob Lustig-Yaeger, a doctoral student for UW-astronomy.
The star is so small, he says, will make the signatures of gases (like carbon dioxide) in the planet’s atmosphere more pronounced in telescope data.
the work informs the scientific community of what we expect to see for the TRAPPIST-1 planet with the upcoming space telescope James Webb. “
Lincowski’s other UW co-author is Victoria Meadows, astronomer professor and director of UW’s astrobiology program. Meadows is also the lead researcher of the NASA Astrobiology Institute’s Virtual Planet Laboratory, based on UW. All authors were affiliates of the research lab.
“The processes that shape the development of an earthly planet are crucial to whether it can be habitable as well as our ability to interpret possible signs of life,” Meadows said. “This paper indicates that we can soon search for potentially detectable sign of these processes on foreign worlds. “
TRAPPIST-1, in the Aquarius constellation, is named after the Basic Transit Planet and Planetesimals Small Telescope, the facility that first found evidence of planets around 2015.