Comet Pan-STARRS Marches Across the Sky

NASA's NEOWISE mission captured a series of infrared images of comet C/2012 K1 -- also referred to as comet Pan-STARRS -- as it swept across our skies in May 2014.  Full image and caption

 

NEOWISE Spies Comet Pan-STARRS Against Galaxy Backdrop

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NASA's NEOWISE mission captured a series of pictures of comet C/2012 K1 -- also known as comet Pan-STARRS -- as it swept across our skies in May 2014.

The comet is named after the astronomical survey project called the Panoramic Survey Telescope and Rapid Response System in Hawaii, which discovered the icy visitor in May 2012. 

Comet Pan-STARRS hails from the outer fringes of our solar system, from a vast and distant reservoir of comets called the Oort cloud. 

The comet is relatively close to us -- it was only about 143 million miles (230 million kilometers) from Earth when this picture was taken. It is seen passing a much more distant spiral galaxy, called NGC 3726, which is about 55 million light-years from Earth, or 2 trillion times farther away than the comet.

Two tails can be seen lagging behind the head of the comet. The bigger tail is easy to see and is comprised of gas and smaller particles. A fainter, more southern tail, which is hard to spot in this image, may be comprised of larger, more dispersed grains of dust.

Comet Pan-STARRS is on its way around the sun, with its closest approach to the sun occurring in late August. It was visible to viewers in the northern hemisphere through most of June. In the fall, after the comet swings back around the sun, it may be visible to southern hemisphere viewers using small telescopes.

The image was made from data collected by the two infrared channels on board the NEOWISE spacecraft, with the longer-wavelength channel (centered at 4.5 microns) mapped to red and the shorter-wavelength channel (3.4 microns) mapped to cyan. The comet appears brighter in the longer wavelength band, suggesting that the comet may be producing significant quantities of carbon monoxide or carbon dioxide.

Originally called the Wide-field Infrared Survey Explorer (WISE), the NEOWISE spacecraft was put into hibernation in 2011 after its primary mission was completed. In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects. NEOWISE is also characterizing previously known asteroids and comets to better understand their sizes and compositions.

NASA's Jet Propulsion Laboratory, Pasadena, California, manages the NEOWISE mission for NASA's Near-Earth Object Observation Program of its Planetary Science Division in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information on NEOWISE is online at: http://www.nasa.gov/wise and http://www.jpl.nasa.gov/wise/

Whitney Clavin
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-4673
whitney.clavin@jpl.nasa.gov

Source: JPL-Caltech

A Possible Naked-eye Comet in March

Far beyond the orbits of Neptune and Pluto, where the sun is a pinprick of light not much brighter than other stars, a vast swarm of icy bodies circles the solar system. Astronomers call it the "Oort Cloud," and it is the source of some of history's finest comets. One of them could be heading our way now.

A new ScienceCast video explores the possibility that Comet Pan-STARRS will be visible to the naked eye in early March. Play it! 

An artist's concept of the Oort cloud. More

Comet Pan-STARRS was discovered by the Panoramic Survey Telescope & Rapid Response System atop the Haleakala volcano in Hawaii. Astronomers use the massive 1.8 meter telescope to scan the heavens for Earth-approaching objects, both asteroids and comets, that might pose a danger to our planet. In June 2011 a comet appeared, and it was named "Pan-STARRS" after  the acronym for the telescope. 

In early March, the comet will pass about 100 million miles from Earth as it briefly dips inside the orbit of Mercury.  Most experts expect it to become a naked-eye object about as bright as the stars of the Big Dipper.

"But" says Karl Battams of the Naval Research Lab, "prepare to be surprised. A new comet from the Oort Cloud is always an unknown quantity equally capable of spectacular displays or dismal failures." 

The Oort cloud is named after the 20th-century Dutch astronomer Jan Oort, who argued that such a cloud must exist to account for all the “fresh” comets that fall through the inner solar system.  Unaltered by warmth and sunlight, the distant comets of the Oort cloud are like time capsules, harboring frozen gases and primitive, dusty material drawn from the original solar nebula 4.5 billion years ago.  When these comets occasionally fall toward the sun, they bring their virgin ices with them. 

Because this is Comet Pan-STARRS first visit, it has never been tested by the fierce heat and gravitational pull of the sun.  "Almost anything could happen," says Battams.  On one hand, the comet could fall apart--a fizzling disappointment.  On the other hand, fresh veins of frozen material could open up to spew garish jets of gas and dust into the night sky.

Because of its small distance from the sun, Pan-STARRS should be very active, producing a lot of dust and therefore a nice dust tail," predicts Matthew Knight of the Lowell Observatory.

"However," he cautions, "it could still be difficult to see.  From our point of view on Earth, the comet will be very close to the sun. This means that it is only observable in twilight when the sky is not fully dark."

The best dates to look may be March 12th and 13th when Pan-STARRS emerges in the western sunset sky not far from the crescent Moon. A comet and the Moon, together, framed by twilight-blue is a rare sight.  "My guess is that the primary feature visible to the naked eye will be the gaseous coma around the head of the comet,” says Knight. “The comet's tail will probably require binoculars or a small telescope."

Two other key dates are March 5th when the comet comes closest to Earth (about 100 million miles away) and March 10th, when the comet comes closest to the sun.  The dose of solar heating it receives just inside the orbit of Mercury could be just what the comet needs to push it into the realm of naked-eye visibility.

Comet Pan-STARRS should not be confused with another, even better comet coming later this year.  In Nov. 2013, Comet ISON could shine as brightly as a full Moon in broad daylight when it passes through the atmosphere of the sun: video.

"Two bright comets in one year is a rare treat," says Battams.  "This could be good."

Author: Dr. Tony Phillips

Production editor: Dr. Tony Phillips  

Credit: Science@NASA