|Animation showing the comet moving against the background of stars. Images taken at the Pan-STARRS 1 Telescope on the night of June 5-6, 2011. Hawaii time is 10 hours earlier than Universal Time (UT). Credit: Henry Hsieh, PS1SC
Astronomers at the University of Hawaii at Manoa have discovered a new comet that they expect will be visible to the naked eye in early 2013.
Originally found by the Pan-STARRS 1 telescope on Haleakala, Maui, on the night of June 5-6, it was confirmed to be a comet by UH astronomer Richard Wainscoat and graduate student Marco Micheli the following night using the Canada-France-Hawaii Telescope on Mauna Kea.
A preliminary orbit computed by the Minor Planet Center in Cambridge, Mass., shows that the comet will come within about 30 million miles (50 million km) of the sun in early 2013, about the same distance as Mercury. The comet will pose no danger to Earth.
Wainscoat said, “The comet has an orbit that is close to parabolic, meaning that this may be the first time it will ever come close to the sun, and that it may never return.”
The comet is now about 700 million miles (1.2 billion km) from the sun, placing it beyond the orbit of Jupiter. It is currently too faint to be seen without a telescope with a sensitive electronic detector.
The comet is expected to be brightest in February or March 2013, when it makes its closest approach to the sun. At that time, the comet is expected to be visible low in the western sky after sunset, but the bright twilight sky may make it difficult to view.
Over the next few months, astronomers will continue to study the comet, which will allow better predictions of how bright it will eventually get. Wainscoat and UH astronomer Henry Hsieh cautioned that predicting the brightness of comets is notoriously difficult, with numerous past comets failing to reach their expected brightness.
Making brightness predictions for new comets is difficult because astronomers do not know how much ice they contain. Because sublimation of ice (conversion from solid to gas) is the source of cometary activity and a major contributor to a comet’s overall eventual brightness, this means that more accurate brightness predictions will not be possible until the comet becomes more active as it approaches the sun and astronomers get a better idea of how icy it is.
The comet is named C/2011 L4 (PANSTARRS). Comets are usually named after their discoverers, but in this case, because a large team, including observers, computer scientists, and astronomers, was involved, the comet is named after the telescope.
C/2011 L4 (PANSTARRS) most likely originated in the Oort cloud, a cloud of cometlike objects located in the distant outer solar system. It was probably gravitationally disturbed by a distant passing star, sending it on a long journey toward the sun.
Comets like C/2011 L4 (PANSTARRS) offer astronomers a rare opportunity to look at pristine material left over from the early formation of the solar system.
The comet was found while searching the sky for potentially hazardous asteroids—ones that may someday hit Earth. Software engineer Larry Denneau, with help from Wainscoat and astronomers Robert Jedicke, Mikael Granvik and Tommy Grav, designed software that searches each image taken by the Pan-STARRS 1 telescope for moving objects. Denneau, Hsieh and UH astronomer Jan Kleyna also wrote other software that searches the moving objects for comets’ tell-tale fuzzy appearance. The comet was identified by this automated software.
The Pan-STARRS 1 telescope has a 1.8-meter-diameter mirror and the largest digital camera in the world (1.4 billion pixels). Each image is almost 3 gigabytes in size, and the camera takes an image approximately every 45 seconds. Each night, the telescope images more than 1,000 square degrees of the night sky.
The Pan-STARRS Project is being led by the University of Hawaii Institute for Astronomy, and exploits the unique combination of superb observing sites and technical and scientific expertise available in Hawaii. Funding for the development of the observing system has been provided by the United States Air Force Research Laboratory. The PS1 Surveys have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network, Incorporated, the National Central University of Taiwan, and the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate. Any opinions, findings, and conclusions or recommendations expressed in this article are those of the author(s), and do not necessarily reflect the views of the National Aeronautics and Space Administration.
Founded in 1967, the Institute for Astronomy at the University of Hawaii at Manoa conducts
research into galaxies, cosmology, stars, planets, and the
sun. Its faculty and staff are also involved in astronomy education,
deep space missions, and in the development and management
of the observatories on Haleakala and Mauna Kea.
Established in 1907 and fully accredited by the Western Association
of Schools and Colleges, the University of Hawaii is the state's
sole public system of higher education. The UH System provides
an array of undergraduate, graduate, and professional degrees
and community programs on 10 campuses and through educational,
training, and research centers across the state. UH enrolls
more than 50,000 students from Hawaii, the U.S. mainland, and
around the world.