• chevron_right

    Webb Telescope confirms nearby rocky planet has no significant atmosphere / ArsTechnica · Monday, 27 March - 19:10 · 1 minute

Image of a grey planet orbiting a dim red star.

Enlarge / An illustration of what the inner portion of the TRAPPIST-1 system might look like. (credit: NASA, ESA, CSA, J. Olmsted (STScI), T. P. Greene (NASA Ames), T. Bell (BAERI), E. Ducrot (CEA), P. Lagage (CEA) )

At this point, we've discovered lots of exoplanets that fall under the general label "Earth-like." They're rocky, and many orbit at distances from their host stars to potentially have moderate temperatures. But "like" is doing a lot of work there. In many cases, we have no idea whether they even have an atmosphere, and the greenhouse effect means that the atmosphere can have a huge impact on the planet's temperature. So the Earth-like category can include dry, baking hellscapes like Venus with its massive atmosphere, as well as dry, frozen tundras with sparse atmospheres like Mars.

But we're slowly getting the chance to image the atmospheres of rocky exoplanets. And today, researchers are releasing the results of turning the Webb Space Telescope on a rocky planet orbiting a nearby star, showing that the new hardware is so sensitive that it can detect the star blocking out light originating from the planet. The results suggest that the planet has very little atmosphere and is mostly radiating away heat from being baked by its nearby star.

The ultra-cool dwarf and its seven planets

TRAPPIST-1 is a small, reddish star—in astronomical terminology, it's an "ultra-cool dwarf"—that's about 40 light-years from Earth. While the star itself is pretty nondescript, it's notable for having lots of planets, with seven in total having been identified so far. All of these are small, rocky bodies, much like the ones that occupy the inner portion of our Solar System. While the star emits very little light, the planets are all packed in closer to it than Mercury is to the Sun.

Read 14 remaining paragraphs | Comments

  • chevron_right

    Putting together the Webb telescope’s mid-infrared eyes / ArsTechnica · Wednesday, 10 August, 2022 - 16:56

Image of an oval-shaped galaxy.

Enlarge / The dust in this galaxy, shaded red, required the MIRI instrument to resolve. (credit: NASA, ESA, CSA, STScI )

There is more than one reason why the Mid-Infrared Instrument (MIRI) on board the James Webb Space Telescope (JWST) is considered to be pioneering. Of the four instruments on JWST, it's the only one that observes in the mid-infrared range, from 5 to 28 microns; the other three are near-infrared devices with a wavelength range of 0.6 to 5 microns. To reach these wavelengths, MIRI had to be kept the coldest of any instrument on JWST, meaning it essentially set the requirements for the telescope’s cooling system.

The stunning images taken by MIRI are a testimony to the remarkable engineering feats that went into it, feats that were achieved by overcoming formidable challenges through meticulous transatlantic teamwork and coordination.

Making MIRI

“I remember being told in the early days that the instrument will never be built. Some people at NASA looked at the block diagram of our management structure and said it will never work,” Professor George Rieke, who leads the science team of MIRI, recalled.

Read 19 remaining paragraphs | Comments