Monday, July 18, 2016

New, Large Asteroid Found in Outer Solar System

Slow-motion of image of newly-
discovered Asteroid 2015 RR245,
in the Outer Solar System.
(Image Source: Outer Solar System Origins
Survey Team)

By Glenn A. Walsh
Reporting for SpaceWatchtower

A new, large asteroid has been found in the Kuiper Belt of the Outer Solar System. In fact due to the current size estimates of the Asteroid / Minor Planet named 2015 RR245, some scientists wonder if it should be designated as a Dwarf Planet.

Although first spotted last September 9 (hence, the 2015 designation), it was not until subsequent observations of the object in February and June when astronomers concluded that 2015 RR245 was a large asteroid. It was first spotted by J.J. Kavelaars of the National Research Council of Canada, using the Canada-France-Hawaii Telescope on top of Mauna Kea in Hawaii.

These observations were part of the four-year Outer Solar System Origins Survey (OSSOS), which started in February of 2013. Involving more than 40 scientists at institutes in 8 countries, this international collaboration seeks to discover distant moving objects in the Outer Solar System, which may allow the scientists to test models regarding how our Solar System evolved.

Using follow-up images of this asteroid in February and June, taken by Michele Bannister of the University of Victoria, more specific estimates of the object were derived. The “year” of 2015 RR245 (i.e. the time it takes to make one revolution around the Sun) is 730 Earth years.

The eccentric orbit of this asteroid takes it to a maximum distance from the Sun of 11.9 billion miles / 19.2 billion kilometers. However, the current location of 2015 RR245 in its orbit means the object is now approaching the Sun (possibly, one of the reasons we now found this object). At its closest, the orbit will bring 2015 RR245 as close as 3.1 billion miles / 5 billion kilometers to the Sun in the year 2096. Currently, this Kuiper Belt object is about 5.9 billion miles / 9.5 billion kilometers from the Sun.

The size of the object is more indefinite. With an apparent visual magnitude in the Mauna Kea telescope of 22, it may be as large as 450 miles / 700 kilometers across. This estimate goes on the assumption that the object's surface is only reflecting 10 per-cent of sunlight.

However, if the object's surface has a lot of ice, it may be reflecting as much as 25 per-cent of sunlight. Hence, such a brighter object may only be about 279 miles / 450 kilometers across.

The size of the object is one determinant of its eligibility to be considered a Dwarf Planet. Thus far, the International Astronomical Union (IAU) has designated, officially, only 5 Dwarf Planets: Asteroid Ceres, Pluto, and three other (besides Pluto) objects beyond the orbit of Neptune (known as Trans-Neptune objects): Eris, Haumea, and Makemake. A sixth Trans-Neptune object, 2007 OR10, is considered large enough to someday be designated as a Dwarf Planet.

Although no other, official, Dwarf Planets have been designated, thus far, the IAU criteria for such designations means that several more Trans-Neptune objects may qualify. And, 2015 RR245 may eventually be one of them.

The IAU's Minor Planet Center, which operates at the Smithsonian Astrophysical Observatory along with the Harvard College Observatory in Cambridge, Massachusetts, has catalogued 1,491 Trans-Neptune objects, as well as another 501 objects with odd, very elliptical orbits in the Outer Solar System. With continuing astronomical observations of the Outer Solar System, they usually find a new Trans-Neptune object every week! However, most of these objects are much, much smaller than 2015 RR245.

Internet Links to Additional Information ---

Canada-France-Hawaii Telescope Announcement of Discovery of 2015 RR245:
Link >>>

More details regarding 2015 RR245 - Minor Planet Electronic Circular 2016-N67:
Link >>>

More on the Outer Solar System Origins Survey: Link >>>

More on the Canada-France-Hawaii Telescope:
Link >>>

More on the Kuiper Belt: Link >>>

More on Dwarf Planets: Link >>>

Source: Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of the Zeiss.
             2016 July 18.

                                                               Historic 10-inch Siderostat-type Refractor Telescope at Pittsburgh's original Buhl Planetarium and Institute of Popular Science.
        2016: 75th Year of Pittsburgh's Buhl Planetarium Observatory
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