Iron rain on exoplanet is driven by huge extremes in temperature
Friday, March 27, 2020 IST
It could be raining molten iron on some exoplanets, according to David Ehrenreich at the University of Geneva and an international team of astronomers. The team discovered evidence for the metallic precipitation in atmospheric spectra of the giant, ultra-hot planet WASP-76b that is about 390 light-years from Earth. Their findings could provide new insights into the exotic chemistry that plays out in the atmospheres of such hot gas giants.
“Hot Jupiters” such as WASP-76b comprise a widely studied group of giant exoplanets that orbit close to their host stars, where they can experience daytime temperatures exceeding 2000 K. Such conditions are extreme enough to break down molecules in the planets’ atmospheres into individual atoms, which recombine back into molecules during the cooler nights. Clearly, this effect would produce extreme differences in atmospheric chemistry between both sides of these planets, but so far, astronomers have not confirmed this asymmetry through direct observations.
In the new study, Ehrenreich’s team has measured such a chemical gradient for the first time, using the ESPRESSO spectrograph at the Very Large Telescope (VLT) in Chile. With the instrument, the researchers could collect light from any combination of the VLT’s four 8-metre telescopes. This provided them with sufficiently high spectral resolution to check for differences in the absorption spectra produced by the atmosphere on the day and night sides of WASP-76b as it passed in front of its host star. In particular, they looked for a gap in the star’s spectrum corresponding to the characteristic wavelengths absorbed by atomized, or “neutral” iron.
Dusk and dawn
Because of the orientation of a transiting exoplanet, it is difficult to obtain its day- and night-time spectra. This is because (from our perspective) the day side is on the far side of the planet and the night side is always dark. However, Ehrenreich and colleagues could observe the atmosphere during dusk and dawn by focusing on the ring of starlight that passes straight through WASP-76b’s atmosphere. As Ehrenreich’s team had predicted, a neutral iron absorption line is visible on WASP-76b’s evening side, but not on its morning side.
The observation confirmed that neutral iron is indeed produced on WASP-76b during hottest part of the day – but becomes far less abundant over the course of the night. Overall, these observations suggest that neutral iron in the atmosphere of WASP-76b condenses during the night to form clouds of liquid droplets – the most stable form of recombined iron atoms. This could then cause molten iron to rain down on the exoplanet during the night, before being atomized again during the day. In the future, Ehrenreich’s team hope that the process could be understood in more detail through 3D global climate models.
Related Topics
Related News & Articles
Venice in Italy was under water on Tuesday after a newly installed system of mobile artificial dams failed to activate.
Recently posted . 549 views . 1 min read
However unusual it may sound but it is true! China has a train called the ‘Y999 Love-Pursuit Train’ and the sole purpose of the train is that all the si...
Recently posted . 758 views . 3 min read
Local media reported that some injuries -- the first resulting from an accident involving an automated train in 30 years -- appeared to be serious but non-life-th...
Recently posted . 621 views . 2 min read
On social media there was amazement at how disciplined the ducks were, waddling together in formation.
Recently posted . 555 views . 1 min read
Saudi Arabia, Egypt, the United Arab Emirates and Bahrain disjoined their ties with Qatar on Monday, blaming the affluent Gulf Arab state for supporting terrorism.<...
Recently posted . 906 views . 21 min read
Trending News & Articles
ALMATY: Hour upon hour, day upon day, Omir Bekali and other detainees in far western China's new indoctrination camps had to disavow the...
Recently posted . 199K views . 1 min read
If you have payed attention to the belly buttons of people on the beach or the members of your family, you have probably noticed that they have different shapes and...
Recently posted . 8K views . 2 min read
In this age of terror, there might be nothing more terrifying than the thought of an attack carried out with chemical weapons. We’ve all heard the horrific ...
Recently posted . 3K views . 4 min read
Body fitness is one thing that everyone wants to maintain irrespective of age. Going to the gym and doing some great exercise always helps to maintain your body fit...
Recently posted . 3K views . 2 min read
More in Global
By Marc Champion
For a quarter century, the US and its allies owned the skies, fighting wars secure in the k...
Recently posted. 718 views . 2 min read
Thomas Markle said that Meghan had not sent him a Christmas card but that he was hopeful that they could at some time build their relationship.
Recently posted. 566 views . 1 min read
It will be the 'Godzilla of all divorces', says lawyer as terms of one of the biggest wealth transfers are revealed.
Recently posted. 653 views . 1 min read
Recently posted . 872 views
Recently posted . 880 views
Recently posted . 1K views
Recently posted . 1K views
Recently posted . 1K views . 49 min read
Recently posted . 1K views . 99 min read
Scientists used computer algorithms to "evolve" an organism that's made of 100% frog DNA — but it isn't a frog.
Recently posted. 547 views . 1 min read
When Vistara’s brand new Boeing 787-9 Dreamliner arrived in Delhi on the 29th February, it made history in so many ways. It was the first widebody for Vistara...
Recently posted. 636 views . 2 min read