The James Webb Space Telescope plans to explore strange new rocky worlds with unprecedented detail.
The telescope’s scientific consortium has an ambitious agenda to study the geology of these small planets “50 light-years away,” they said in a statement Thursday (May 26th). The work will be a major stretch for the new observatory, which should be out of operation in a few weeks.
Rocky planets are harder to see than gas giants in current telescope technology, due to the relative brightness of the smaller planets next to a star and their relatively small size. But Webb’s powerful mirror and deep space location should allow us to examine two slightly larger planets than Earth, known as “super-Earths.”
None of these worlds are habitable as we know them, but researching them could still be a testing ground for future in-depth studies of planets like ours. The two planets highlighted by Webb officials include 55 Cancri e, which is superheated and covered in lava, and LHS 3844 b, which has no substantial atmosphere.
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Illustration comparing two rocky exoplanets with Earth and Neptune. In order of appearance, from left to right, there is the Earth (based on data from the Deep Space Climate Observatory), LHS 3844 b (an illustration), 55 Cancri e (an illustration) illustration) and Neptune (based on data from Voyager 2). (Image credit: NASA, ESA, CSA, Dani Player (STScI)) (opens in a new tab)
55 Cancer orbits its parent star at about 2.4 million km (1.5 million miles), about four percent of the relative distance between Mercury and the Sun.
Around its star only once every 18 hours, the planet has blast furnace surface temperatures above the melting point of most types of rocks. Scientists also assumed that the planet is blocked by the star, meaning that one side always faces the scorching sun, although observations from NASA’s Spitzer Space Telescope suggest that the hottest area could be slightly compensated.
Scientists say the compensated heat could be due to a thick atmosphere that can move heat around the planet, or because it rains lava at night in a process that removes heat from the atmosphere. (Night lava also suggests a day-night cycle, which could be due to a 3: 2 resonance, or three rotations for every two orbits, which we see on Mercury in our own solar system.)
Two teams will test these hypotheses: one led by NASA’s Jet Propulsion Laboratory research scientist Renyu Hu will examine the planet’s thermal emission for atmospheric signs, while a second team led by Alexis Brandeker, an associate professor at the University of ‘Stockholm will measure the heat. emission of the illuminated side of 55 Cancri e.
LHS 3844 b is also a close orbit, which moves around its parent star only once every 11 hours. The star, however, is smaller and cooler than that of 55 Cancri e. Therefore, the planet’s surface is probably much cooler, and Spitzer’s observations have shown that there is probably no substantial atmosphere present on the planet.
A team led by astronomer Laura Kreidberg of the Max Planck Institute for Astronomy hopes to capture a signal from the surface by spectroscopy, in which different wavelengths of light suggest different elements. The light emission spectra on the light side of the planet will be compared to rocks known as basalt and granite to see if they can deduce a surface composition.
The two investigations “will give us fantastic new perspectives on Earth-like planets in general, helping us learn what the primitive Earth might have been like when it was hot like these planets today,” Kreidberg said in the same statement.
Webb is now working through state-of-the-art start-up procedures, such as tracking targets in the solar system and moving between warmer and colder attitudes to test the strength of his mirror and the alignment of instruments. The $ 10 billion observatory is expected to complete its commissioning around June and move on to its observation cycle 1 shortly thereafter.
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