An Evaporating Exoplanet?
(Artist rendering of an exoplanet atmosphere “evaporating” near its host star. Credit: ESA / Alfred Vidal-Madjar, Institut d’Astrophysique de Paris, CNRS, France)
“There’s something strange obscuring the light from a cool, low-mass star observed by NASA’s Kepler mission. Every 15.685 Earth days, KIC 12557548’s light dims for about 1.5 hours. The dips in starlight aren’t always the same — some events block more light than others — so the occultations don’t look like the regular blip caused by a planet passing in front of the star. After considering various options, an international team of astronomers reported recently that the signal might be from debris thrown off by a small rocky planet as it disintegrates under the star’s glare.”
“Astronomers found what looks like an evaporating gas giant in 2003, but if real KIC 12557548’s world would be the first solid exoplanet seen dematerializing.”
“Spectral observations may be able to determine if the planet and its tail are there and what the tail is made of. The astronomers put their bet on pyroxene, a silicate mineral found in Earth’s crust and mantle (and in meteorites) that should survive close proximity to KIC 12557548 long enough to block starlight before the grains vaporize.”
We’re getting close to making firm detections of Earth-like exoplanets, not only in terms of size, density, and other physical properties, but in their compositions. Astronomers are still novices in the business of understanding exoplanets’ detailed characteristics, and are not entirely sure what variety of possible planets exists. The detection of silicate minerals around an exoplanet host star would lend support to the idea that some of these extraterrestrial worlds are of a rather similar composition to our own home. The closer we come to finding planets like our own, the closer we may be to answering the ultimate question: do any of them harbor life? -JCB
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