Gemini Observatory | University of Hawaii Institute for Astronomy | 2014 Nov 10
[c][attachment=0]Meech_images[1].jpg[/attachment][/c]Astronomers are announcing today the discovery of two unusual objects in comet-like orbits that originate in the Oort cloud but with almost no activity, giving scientists a first look at their surfaces. These results, presented today at the annual meeting of the Division of Planetary Sciences of the American Astronomical Society in Tucson, Arizona, are particularly intriguing because the surfaces are different from what astronomers expected, and they give us clues about the movement of material in the early solar system as the planets were assembled.
On August 4, 2013 an apparently asteroidal object, C/2013 P2 Pan-STARRS, was discovered by the Pan STARRS1 survey telescope (PS1) on Haleakala, Maui, Hawaii. What made this object unique is its orbit – that of a comet coming from the Oort cloud, with an orbital period greater than 51 million years, yet no cometary activity was seen. The Oort cloud is a spherical halo of comet nuclei in the outer solar system that extends to about 100,000 times the Earth-sun distance, which is known as 1 astronomical unit, or 1 AU. ...
Follow-up observations in September 2013 with the 8-meter Gemini North telescope on Mauna Kea, Hawaii, hinted at faint, low-level light reflected off a dusty tail. This tail remained through the object’s closest approach to the sun (2.8 times the Earth-sun distance, within the outer asteroid belt) in February 2014, but the object didn’t get much brighter.
When the object was observable again in the spring, the team used the Gemini North telescope to obtain a spectrum of the surface, which showed that it was very red, completely different from comet or asteroid surfaces, and more like the surface of an ultra-red Kuiper belt object. ...