Komet 252P/LINEAR's kerne og inderste koma
Komet 252P/LINEAR's kerne og inderste koma

Da komet 252P/LINEAR passerede tæt forbi Jorden 21 marts 2016 i en afstand af kun 2 mio km , havde man en unik lejlighed til at få nærbilleder af kometen. Hubble rumteleskopet var i en perfekt vinkel til at fotografere den og det lykkedes at få billeder af selve kernen med en opløsning på kun 1,6km/pixel, som er den bedste oplæsning Hubble indtil nu har kunnet opløse. Dermed kunne man bestemme kometkernens størrelse og den viste sig at være den mindste kometkerne man kender til.Forskenre håber at kunne bruge billederne til at vise hvordan kometer bliver mindre med tiden.

Læs pressemeddelelsen fra Planetary Science Institute herunder NEWS RELEASE FROM THE PLANETARY SCIENCE INSTITUTE FROM: Alan Fischer Public Information Officer Planetary Science Institute 520-382-0411 520-622-6300 Denne e-mail adresse bliver beskyttet mod spambots. Du skal have JavaScript aktiveret for at vise den. Close-Up Hubble Images Show New Details of Comet May 12, 2016, Tucson, Ariz. -- Astronomers using NASA's Hubble Space Telescope captured images of Comet 252P/LINEAR just after a close encounter with Earth on March 21. The close proximity to the comet offered scientists new insights on the body’s nucleus. “Because comets are usually only a few kilometers in size, and probably less than 1 kilometer for this comet, reliable measurement of size is best done when they are close to us. That’s why the close approach to Earth of this comet offered us a great opportunity to study it,” said PSI Senior Scientist Jian-Yang Li, who led this project to observe 252P with HST during its close approach to Earth. The visit was one of the closest encounters between a comet and our planet. The comet traveled within 3.3 million miles of Earth, or about 14 times the distance between our planet and the Moon. “With the small distance of this comet to us, and the high spatial resolution of HST, we reached 1.6 kilometers per pixel resolution, which is the highest for HST ever on a comet,” Li said. “For comparison, ground-based observations of this comet have more than 10 time lower resolution than HST.” The images reveal a narrow, well-defined jet of dust ejected by the comet's icy, fragile nucleus. These observations also represent the closest celestial object Hubble has observed, other than the Moon. The comet will return to the inner solar system again in 2021. “Comet 252P is one of the smallest comets we know of. Our main goal is to determine its size and study how comets become smaller and smaller as they pass around the Sun. From this we will infer the properties of building blocks of planets at the start of the solar system,” Li said. “In addition, we will also study other dynamic properties of the comet, such as its rotation and how it releases dust under the heating of the Sun.” PSI Senior Scientist Nalin Samarasinha also worked on the project, which was funded by a grant to PSI from NASA through Space Telescope Science Institute. Visit http://www.psi.edu/news/cometimages to see images of Comet 252P/LINEAR.