TRAPPIST-1 is a nearby system of seven Earth-sized, temperate, rocky exoplanets transiting a Jupiter-sized ultracool red dwarf, ideally suited for in-depth atmospheric studies. Using the NIRISS instrument aboard the NASA/ESA/CSA James Webb Space Telescope, astronomers have now captured the first transmission spectra of TRAPPIST-1b, the innermost planet in the TRAPPIST-1 system.
TRAPPIST-1 is an ultracool M-dwarf star located 38.8 light-years away in the constellation of Aquarius.
Also known as K2-112 or TIC 278892590, the star is barely larger than Jupiter and has just 8% of our Sun’s mass.
In February 2017, astronomers announced that the star hosts at least seven planets: TRAPPIST-1b, c, d, e, f, g and h.
All these planets are similar in size to Earth and Venus, or slightly smaller, and have very short orbital periods: 1.51, 2.42, 4.04, 6.06, 9.21, 12.35 and 20 days, respectively.
Three of these planets lay in the star’s habitable zone, meaning they may harbor suitable conditions for life.
TRAPPIST-1b, the innermost planet, has an orbital distance about one hundredth that of Earth’s and receives about four times the amount of energy that Earth gets from the Sun.
Although it is not within the habitable zone, observations of the planet can provide important information about its sibling planets, as well as those of other red-dwarf systems.
In the new research, Université de Montréal doctoral student Olivia Lim and her colleagues employed Webb to observe TRAPPIST-1b.
The planet was observed during two transits — the moment when the planet passes in front of its star – using Webb’s NIRISS instrument.
“These are the very first spectroscopic observations of any TRAPPIST-1 planet obtained by Webb, and we’ve been waiting for them for years,” said Lim, the lead author of a paper published in the Astrophysical Journal Letters.
The astronomers used the technique of transmission spectroscopy to peer deeper into the distant world.
By analyzing the…
Read the full article here