[meteorite-list] NASA Spots the 'Great Pumpkin': Halloween Asteroid a Treat for Radar Astronomers
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 21 Oct 2015 17:16:00 -0700 (PDT)
NASA Spots the 'Great Pumpkin': Halloween Asteroid a Treat for Radar Astronomers
October 22, 2015
This is a graphic depicting the orbit of asteroid 2015 TB145. The
asteroid will safely fly past Earth slightly farther out than the moon's
orbit on Oct. 31 at 10:05 a.m. Pacific (1:05 p.m. EDT and 17:05 UTC).
Image credit: NASA/JPL-Caltech
NASA scientists are tracking the upcoming Halloween flyby of asteroid
2015 TB145 with several optical observatories and the radar capabilities
of the agency's Deep Space Network at Goldstone, California. The
asteroid will fly past Earth at a safe distance slightly farther than
the moon's orbit on Oct. 31 at 10:05 a.m. PDT (1:05 p.m. EDT).
Scientists are treating the flyby of the estimated 1,300-foot-wide
(400-meter) asteroid as a science target of opportunity, allowing
instruments on "spacecraft Earth" to scan it during the close pass.
Asteroid 2015 TB145 was discovered on Oct. 10, 2015, by the University
of Hawaii's Pan-STARRS-1 (Panoramic Survey Telescope and Rapid Response
System) on Haleakala, Maui, part of the NASA-funded Near-Earth Object
Observation (NEOO) Program. According to the catalog of near-Earth
objects (NEOs) kept by the Minor Planet Center, this is the closest
currently known approach by an object this large until asteroid 1999
AN10, at about 2,600 feet (800 meters) in size, approached at about 1
lunar distance (238,000 miles from Earth) in August 2027.
Another view of the orbit of asteroid 2015 TB145.
Image credit: Paul Chodas/JPL
"The trajectory of 2015 TB145 is well understood," said Paul Chodas,
manager of the Center for Near Earth Object Studies at NASA's Jet
Propulsion Laboratory, Pasadena, California. "At the point of closest
approach, it will be no closer than about 300,000 miles -- 480,000
kilometers or 1.3 lunar distances. Even though that is relatively close
by celestial standards, it is expected to be fairly faint, so night-sky
Earth observers would need at least a small telescope to view it."
The gravitational influence of the asteroid is so small it will have no
detectable effect on the moon or anything here on Earth, including our
planet's tides or tectonic plates.
The Center for NEO Studies at JPL is a central node for NEO data
analysis in NASA's Near-Earth Object Observation Program and a key group
involved with the international collaboration of astronomers and
scientists who keep watch on the sky with their telescopes, looking for
asteroids that could be a hazard to impact our planet and predicting
their paths through space for the foreseeable future.
"The close approach of 2015 TB145 at about 1.3 times the distance of the
moon's orbit, coupled with its size, suggests it will be one of the best
asteroids for radar imaging we'll see for several years," said Lance
Benner, of JPL, who leads NASA's asteroid radar research program. "We
plan to test a new capability to obtain radar images with two-meter
resolution for the first time and hope to see unprecedented levels of
During tracking, scientists will use the 34-meter (110-foot) DSS 13
antenna at Goldstone to bounce radio waves off the asteroid. Radar
echoes will in turn be collected by the National Radio Astronomy
Observatory's Green Bank Telescope in Green Bank, West Virginia, and the
National Astronomy and Ionosphere Center's Arecibo Observatory, Puerto
Rico. NASA scientists hope to obtain radar images of the asteroid as
fine as about 7 feet (2 meters) per pixel. This should reveal a wealth
of detail about the object's surface features, shape, dimensions and
other physical properties.
"The asteroid's orbit is very oblong with a high inclination to below
the plane of the solar system," said Benner. "Such a unique orbit, along
with its high encounter velocity -- about 35 kilometers or 22 miles per
second -- raises the question of whether it may be some type of comet.
If so, then this would be the first time that the Goldstone radar has
imaged a comet from such a close distance."
NASA's Near-Earth Object Observations Program detects, tracks and
characterizes asteroids and comets passing within 30 million miles of
Earth using both ground- and space-based telescopes. The NEOO Program,
sometimes called "Spaceguard," discovers these objects, characterizes
the physical nature of a subset of them, and predicts their paths to
determine if any could be potentially hazardous to our planet. There are
no known credible impact threats to date -- only the ongoing and
harmless in-fall of meteoroids, tiny asteroids that burn up in the
JPL hosts the Center for Near-Earth Object Studies for NASA's Near-Earth
Object Observations Program within the agency's Science Mission
Directorate. JPL is a division of the California Institute of Technology
More information about asteroids and near-Earth objects is at:
Jet Propulsion Laboratory, Pasadena, Calif.
agle at jpl.nasa.gov
Received on Wed 21 Oct 2015 08:16:00 PM PDT