What’s that? You never met Herschel?
ESA’s Herschel space observatory has discovered water vapour around Ceres, the first unambiguous detection of water vapour around an object in the asteroid belt.
With a diameter of 950 km, Ceres is the largest object in the asteroid belt, which lies between the orbits of Mars and Jupiter. But unlike most asteroids, Ceres is almost spherical and belongs to the category of ‘dwarf planets’, which also includes Pluto ….
…. [U]sing the HIFI instrument on Herschel to study Ceres, scientists have collected data that point to water vapour being emitted from the icy world’s surface.
“This is the first time that water has been detected in the asteroid belt, and provides proof that Ceres has an icy surface and an atmosphere,” says Michael Küppers of ESA’s European Space Astronomy Centre in Spain, lead author of the paper published in Nature.
Although Herschel was not able to make a resolved image of Ceres, the astronomers were able to derive the distribution of water sources on the surface by observing variations in the water signal during the dwarf planet’s 9-hour rotation period. Almost all of the water vapour was seen to be coming from just two spots on the surface.
“We estimate that approximately 6 kg of water vapour is being produced per second, requiring only a tiny fraction of Ceres to be covered by water ice, which links nicely to the two localised surface features we have observed,” says Laurence O’Rourke, Principal Investigator for the Herschel asteroid and comet observation programme called MACH-11, and second author on the Nature paper.
And, really, what can you say? Good show, Herschel. Congratulations, ESA. And thank you. That is really, really cool.
Herschel is named for the guy who discovered Uranus; William Herschel also identified infrared radiation over two hundred years ago. This latest announcement is one of the satellite’s last dramatic gifts; Herschel ran its course, with final commands sent in June, 2013.
It was certainly a good run. And there are probably myriad little gifts remaining to be discovered in the data.
Talk about a show. Water at Ceres. Makes as much sense as anything else, to be certain, but it is also good to know.