The interplanetary station Rosetta measured the surface temperature of the comet Churyumov-Gerasimenko
Only 2 days are left before the planned approach of Rosetta station to comet Churyumov-Gerasimenko (this event should happen on August 6). Nevertheless, many measurements of various characteristics of the comet, including the size of the nucleus, the rate of evaporation of water have already been made.
Now the temperature of the comet's nucleus has also been measured. Looking ahead, it is worth mentioning that the comet's core is covered with dark dust, which leads to an increase in temperature. This, in turn, means that not all of the comet's nucleus is covered with ice, in some parts of the nucleus the temperature is too high for the formation of an ice crust on the surface.
Temperature measurements were taken with the VIRTIS instrument, between July 13 and 21. Then the distance of the station to the comet decreased from 14,000 kilometers to only 5,000 kilometers.
At this distance, the Rosetta station saw a comet in the size of several pixels. The VIRTIS instrument made it possible to measure the thermal radiation of the comet, as a result of which it was found that the average temperature of this cosmic body is -70 degrees Celsius. This is about 20-30 degrees warmer than necessary so that the ice completely covers the entire core.
The measurement results allowed us to draw the first conclusions about the physical properties of the surface of the comet's nucleus and its structure. Now scientists suggest that the comet's nucleus is covered with dark dust, which is the cause of the increased temperature of the nucleus. Soon, using VIRTIS, it will be possible to build a detailed heat map of the comet, both current, static, and “seasonal”, with a map of the change in core temperature depending on the influence of the Sun.
Now the distance to the comet is only slightly more than 100 kilometers - the planned distance of the approach of the Rosetta station to the comet.