- 3941 -
RED DWARF WITH PLANETS? Astronomers have been excited that some of
Trappist-1's seven rocky planets could be habitable. The James Webb Space Telescope has measured
the temperature of a rocky exoplanet for the first time, finding that a
"cousin" of Earth most likely lacks an atmosphere.
------------ 3941 - RED DWARF WITH PLANETS?
- When the
Trappist-1 system was discovered in 2017, astronomers were excited at the
prospect that some of its seven rocky planets, which are roughly similar to
Earth in size and mass, could be habitable.
-
- Just 40
light years from Earth, the planets orbit much closer to their ultracool red
dwarf star than the rocky planets in our Solar System. But their star gives off
far less energy than our Sun.
-
- The system
made an obvious target for the Webb telescope, which has unleashed a torrent of
scientific discovery since releasing its first observations in July last year,
2022.
-
- Astronomers
focused on Trappist-1b, the closest planet to the red dwarf, because it was the
easiest to spot. Webb's Mid-Infrared
Instrument (MIRI) measured the change in brightness when the planet moved
behind its star, in what is known as a secondary eclipse.
-
- Just before
disappearing behind the star, the planet gives off the most light because it
almost exclusively shows its 'day' side.
By subtracting the brightness of the star, the researchers calculated
how much infrared light the planet was giving off.
-
- The MIRI
instrument was able to act like "a giant touch-free thermometer. 'Perfect for baking pizza'. The planet's dayside temperature was
determined to be 450 Fahrenheit.
-
- The
scientists therefore concluded that Trappist-1b has little or no
atmosphere. Other wavelengths would need
to be analyzed to confirm this result.
But, it was certain that the atmosphere did not contain carbon dioxide,
because that would have absorbed some of the light.
-
- The ability
to analyze the potential atmospheres of such rocky exoplanets opens "a new
era" in the study of planets outside our Solar System. It was already known that Trappist-1b was
uninhabitable, as it is too close to its star.
But Trappist-1e, Trappist-1f and Trappist-1g are all thought to be in
what is called the "goldilocks zone".
-
- Planets in
this zone have a moderate temperature which could support liquid water
considered essential for life anywhere
-
April 1, 2023 RED
DWARF WITH PLANETS? 3926
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--- Sunday, April 2, 2023
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