Saturday, October 1, 2016

Rosetta looked at the girl the production of water using the comet – Science In Poland (PAP)

over the last two years, the Rosetta probe followed the properties of comet 67P/Churyumov-Gerasimenko. In particular, the researchers investigated how much steam coming out of the comet in outer space. This week was published a new research results, – said the ESA.

As reported by the European Space Agency (ESA), a recent study conducted a team of scientists, led by Kenneth S. Hansen of the University of Michigan in the United States. The researchers analyzed production rates of water, based on the data collected by the ROSINA instrument operating on Board the Rosetta probe, comparing them with information collected through other tools. For the analysis had a nearly two-year observation period.

it Turns out that from the moment when Rosetta reached the comet (i.e. August 2014), production of water yield increase from a few tens of thousands of pounds daily more than 100 million pounds per day at the moment when the comet passed through the perihelion (point of orbit closest to the Sun), that is, in August 2015. After peaking during this period, water production has decreased in the months following, but slowly.

the Simplest model to describe this phenomenon is the distribution of water in the form of a spherical gas around the comet. However, due to the complex shape of the comet and the occurrence of seasonal cycles, this model is not too good to describe reality. Therefore, scientists have developed a number of more complex digital simulation, which presented in one of the other articles.

based On simulation data, which show that the rate of production of water for kometach such as 67P/Churyumov-Gerasimenko is very heterogeneous, team Hansen has developed a model experience for this particular comet, and applied it to data gathered by the ROSINA instrument.

the Results show that during the first few months of observations, when the comet was at a distance of from 3.5 to 1.7 astronomical units from the Sun, the water was produced mainly in the Northern hemisphere of the comet. Then, in may 2015. completed a 5.5-year-old summer in the Northern hemisphere and began a period of short but intense summer the southern hemisphere kometarnego kernel. Then the comet was at 1.7 astronomical units from the Sun. Contrary to forecasts, which assumed a gradual transition of production water from the Northern hemisphere to the South, this process was completed, of course, gwałtowniej. Maximum water production was in accordance with expectations, in the period from late August to early September, 2015, approximately three weeks after the perihelion passage.

based On the obtained results, the scientists calculated that during the period in which followed the comet probe Rosetta, the object is lost in space, 6.4 billion pounds of water. And the total mass loss, after accounting for other gas molecules and dust, could be even 10 times more. If the nucleus of the comet was a perfect ball, and now its diameter as a result of this weight loss of 2 to 4 meters.

the Results were published in the scientific journal Monthly Notices of the Royal Astronomical Society”.

the mission of the Rosetta probe will conclude on Friday 30 September 2016. The European Space Agency (ESA) is planning a controlled fall of the probe on the comet surface. (PAP)

cha/ mrt/


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