Rocky Worlds Orbiting Star 40 Light Years From Earth Say Astronomers

Posted on July 20, 2016

A team of astronomers say there are three potentially habitable planets orbiting a star named TRAPPIST-1, which is about 40 light years from Earth. TRAPPIST-1 is an ultracool dwarf star. The astronomers say there are regions of each planet may be suitable for life. Two of the planets are primarily rocky according to a new study.

The astronomers from MIT, the University of Li├Ęge, and elsewhere say the atmosphere of the innermost planets are compact, similar to the atmospheres of Earth, Venus, and Mars. The scientists were led by first author Julien de Wit, a postdoc in MIT's Department of Earth, Atmospheric and Planetary Science.

Julien de Wit says in a statement, "We thought, maybe we could see if people at Hubble would give us time to do this observation, so we wrote the proposal in less than 24 hours, sent it out, and it was reviewed immediately. Now for the first time we have spectroscopic observations of a double transit, which allows us to get insight on the atmosphere of both planets at the same time. The data turned out to be pristine, absolutely perfect, and the observations were the best that we could have expected. The force was certainly with us."

De Wit also says, "Now we can say that these planets are rocky. Now the question is, what kind of atmosphere do they have? The plausible scenarios include something like Venus, where the atmosphere is dominated by carbon dioxide, or an Earth-like atmosphere with heavy clouds, or even something like Mars with a depleted atmosphere. The next step is to try to disentangle all these possible scenarios that exist for these terrestrial planets."

The researchers plan to gain access to more telescopes to study the planets. A research paper on the findings was published in the journal, Nature.

The astronomers also note in the paper that inner two planets receive four times and two times the irradiation of Earth, respectively. They say the data they recorded suggests that 11 orbits remain possible for the third planet. The most probably of these possible orbits results in irradiation significantly less than that received by Earth.

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