HALEAKALA - University of Hawaii astronomers have discovered a new comet they expect will be visible to the naked eye in early 2013, the UH Institute for Astronomy announced Thursday.
The scientists originally found the comet using the Pan-STARRS PS1 telescope and automated software atop Haleakala on the night of June 5-6, and the discovery 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 atop Mauna Kea on the Big Island.
The comet poses no danger to Earth, institute officials said. But a preliminary orbit computation by the Minor Planet Center in Cambridge, Mass., found that in early 2013 the comet will come within about 30 million miles of the sun, about the same distance of Mercury to the sun.
"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," Wainscoat said.
Institute officials said the comet was about 700 million miles from the sun, putting it beyond the orbit of Jupiter. Now, it is too faint to be seen without a telescope equipped with a sensitive electronic detector.
The comet is expected to be brightest in February or March 2013, when it will be closest to the sun, officials said. Then, it should be visible low in the western sky after sunset, "but the bright twilight sky may make it difficult to see."
The astronomers said they will continue to study the comet, particularly to predict how bright it will eventually become.
Wainscoat and UH astronomer Henry Hsieh cautioned that predicting the brightness of comets is "notoriously difficult." Numerous past comets have failed to reach their expected brightness, they said.
Predicting the brightness of comets is difficult, the scientists said, because astronomers don't know how much ice they contain.
The conversion of ice from solid to a gas is the major contributor to a comet's overall brightness, they said. Scientists will be better able to predict the comet's brightness when it approaches the sun and astronomers can get a better idea how icy it is.
The comet is named C/2011 L4 (PANSTARRS), institute officials said. 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.
Officials said that C/2011 L4 (PANSTARRS) most likely originated in the Oort cloud, a cloud of cometlike objects located in the distant outer solar system. They said it was probably dislodged from its origins by the gravitational pull of a distant passing star, "sending it on a long journey toward the sun."
The scientists said comets like C/2011 L4 (PAN-STARRS) provide astronomers "a rare opportunity to look at pristine material left over from the early formation of the solar system."
Officials said the comet was found while searching the sky for potentially hazardous asteroids - those 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 Pan-STARRS 1 telescope has a 1.8-meter mirror and the largest digital camera in the world, with 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. Funding for the development of the system has been provided by the U.S. Air Force Research Laboratory.
Pan-STARRS is shorthand for Panoramic Survey Telescope & Rapid Response System. PS1 is the prototype for a battery of four telescopes intended for construction atop Mauna Kea.