Comet 252P/LINEAR
Introduction: For thousands of years, humans have recorded sightings of mysterious comets
sweeping across the nighttime skies. These celestial wanderers, "snowballs" of dust
and ice, are swift-moving visitors from the cold depths of space. Some of them
periodically visit the inner solar system during their journeys around the sun.
Astronomers using NASA's Hubble Space Telescope captured images of Comet
252P/LINEAR just after it swept by Earth on March 21. 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. 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.
The comet will return to the inner solar system again in 2021.
About image: 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.
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.
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 Earth.
These visible-light images were taken with Hubble's Wide Field Camera 3.
For more information, contact:
Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4493 / 410-338-4514
dweaver@stsci.edu / villard@stsci.edu
Jian-Yang Li
Planetary Science Institute, Tucson, Arizona
571-488-9999
jyli@psi.edu
Source: HubbleSite
