December 10, 2013
ISON May Be Dead But The Data Lives On
[ Watch the Video: Comet ISON - Gone But Not Forgotten ]
Lee Rannals for redOrbit.com – Your Universe Online
While the general public is disappointed about the outcome of comet ISON’s perihelion, scientists are thrilled in the data this object was able to bring to the community.
Comet ISON made its closest approach to the sun on Thanksgiving Day, and predictions showed it had a 50/50 shot whether or not the comet would survive. Days after perihelion, scientists saw that only a remnant of ISON actually made it through the pass, making all the projections about the comet being a spectacular site for backyard astronomers fall short. However, a worldwide collaboration is ensuring that comet ISON still lives on in the hearts of scientists.
[ Watch the Video: Comet ISON’s Full Perihelion Pass ]
Observatories around the globe and in space gathered together to watch ISON, creating one of the largest sets of comet observations in history. Researchers presented scientific results from the comet’s last days at the 2013 Fall American Geophysical Union meeting in San Francisco California on Tuesday, describing how the comet lost mass in advance of reaching perihelion and most likely broke up during its closest approach.
"The comet's story begins with the very formation of the solar system," Karl Battams, an astrophysicist at the Naval Research Laboratory in Washington, D.C., said in a statement. "The dirty snowball that we came to call Comet ISON was created at the same time as the planets."
ISON orbited the solar system in the Oort cloud at more than 4.5 trillion miles away from the sun. A few million years ago, something knocked comet ISON off its course and sent it hurling towards the sun.
The comet was first spotted in September 2012, 585 million miles away. The astronomers, Vitali Nevski and Artyom Novichonok, determined that the comet would swing within 1.1 million miles of the sun’s surface, making it a sungrazing comet.
In October 2013, two months before perihelion, NASA’s Mars Reconnaissance Orbiter (MRO) learned that the comet’s nucleus could have been the length of five or six football fields. This size meant the comet was near the borderline of how big ISON needed to be in order to survive perihelion.
NASA’s Solar Terrestrial Observatory and Solar and Heliospheric Observatory were able to pick up on the comet while it was going into perihelion, however the space agency’s Solar Dynamics Observatory (SDO) was not. SDO is tuned to see wavelengths of light that would indicate the presence of oxygen, which is very common in comets.
"The fact that ISON did not show oxygen despite how close it came to the sun provides information about how high was the evaporation temperature of ISON's material," Dean Pesnell, project scientist for SDO at NASA's Goddard Space Flight Center said in a statement. "This limits what it could have been made of."
Comet ISON’s legacy will continue to live on as its ghost emerges alongside scientific data and studies for years to come.