jeudi 12 mai 2016

Hubble Catches Views of a Jet Rotating with Comet 252P/LINEAR












NASA - Hubble Space Telescope patch.

May 12, 2016

This sequence of images taken by NASA’s Hubble Space Telescope shows Comet 252P/LINEAR as it passed by Earth. The visit was one of the closest encounters between a comet and our planet.


Image above: Comet 252P/LINEAR as it passed by Earth. Images Credits: NASA, ESA, and J.-Y. Li (Planetary Science Institute).

The images were taken on April 4, 2016, roughly two weeks after the icy visitor made its closest approach to Earth on March 21. The comet traveled within 3.3 million miles of Earth, or about 14 times the distance between our planet and the moon. These observations also represent the closest celestial object Hubble has observed, other than the moon.

The images reveal a narrow, well-defined jet of dust ejected by the comet’s icy, fragile nucleus. The nucleus is too small for Hubble to resolve. Astronomers estimate that it is less than one mile across. A comet produces jets of material as it travels close to the sun in its orbit. Sunlight warms ices in a comet’s nucleus, resulting in large amounts of dust and gas being ejected, sometimes in the form of jets. The jet in the Hubble images is illuminated by sunlight.

The jet also appears to change direction in the images, which is evidence that the comet’s nucleus is spinning. The spinning nucleus makes the jet appear to rotate like the water jet from a rotating lawn sprinkler. The images underscore the dynamics and volatility of a comet’s fragile nucleus.


Animation above: This time-lapse movie, assembled from Hubble Space Telescope images, shows a narrow, well-defined jet of dust sweeping around with the rotation of Comet 252P/LINEAR like a spinning lawn sprinkler. The jet is illuminated by sunlight. Researchers made the movie from Hubble images taken April 4, 2016, when the comet was 8.7 million miles from Earth. The time interval between each frame is approximately 30 to 50 minutes. The icy body made its closest approach to Earth on March 21, 2016, when it was 3.3 million miles away. It is now more than 25 million miles away from Earth. The jet is composed of material from the comet’s icy nucleus that has been warmed by sunlight and ejected into space. The nucleus is too small for Hubble to resolve. The jet’s changing direction is evidence that the comet’s nucleus is rotating, which makes the jet appear to spin like the water jet from a rotating lawn sprinkler. The movie underscores the dynamics and volatility of a comet’s fragile nucleus. The movie is based on visible-light images taken with Hubble’s Wide Field Camera 3. Animation Credits: NASA, ESA, and J.-Y. Li (Planetary Science Institute).

Comet 252P/LINEAR is traveling away from Earth and the sun; its orbit will bring it back to the inner solar system in 2021, but not anywhere close to the Earth.

These visible-light images were taken with Hubble’s Wide Field Camera 3.

Hubble and the sunrise over Earth

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

For images and more information about Hubble Space Telescope:

    https://www.spacetelescope.org/
    http://hubblesite.org/
    http://www.nasa.gov/hubble

Images (mentioned), Animation (mentioned), Video, Text, Credits: NASA/Ashley Morrow/Space Telescope Science Institute/Donna Weaver/Ray Villard/Planetary Science Institute/Jian-Yang Li/European Space Agency (ESA).

Best regards, Orbiter.ch

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