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Topic Name: Scientists Say Arecibo Astronomers have a Golden Opportunity to Obtain Close Images of a Near-Earth Asteroid in Near Future

Category: STAR (Space, Telecommunications & Radioscience)

Research persons: Michael C. Nolan, Jean-Luc Margot

Location: Cornell University Communications, United States

Details

The Arecibo Observatory in Arecibo, Puerto Rico will observe a newly discovered asteroid on Jan. 27-28, as the object called 2007 TU24 passes within 1.4 lunar distances, or 334,000 miles, from Earth.

The asteroid, estimated at between 150 and 600 meters in diameter – about 500 feet to 1,900 feet, or the size of a football field, at 360 feet, to the size of Chicago’s 110-story Sears Tower, at 1,454 feet – was discovered by the University of Arizona’s Catalina Sky Survey in October 2007. It poses no threat to Earth, but its near approach gives Arecibo astronomers a golden opportunity to learn more about potentially hazardous near-Earth objects.

“We don’t yet know anything about this asteroid,” said Michael C. Nolan, head of radar astronomy at the Puerto Rico observatory. Such objects pass near Earth with relative frequency, he said – approximately one every five years or so – but it’s rare that astronomers have enough advance notice to plan for rigorous observing.

“Because it’s coming so close, we’ll get our highest quality imaging,” said Nolan.

Using Arecibo’s powerful radar, which is the most sensitive in the world, researchers will gauge the object’s size, observe its speed and measure its spin. Switching then to imaging mode, which will offer resolution to 7.5 meters – three times more precise than NASA’s Goldstone telescope, the only other radar telescope in the world – the researchers hope to map the object’s surface in detail. The Robert C. Byrd Green Bank Telescope, Green Bank, W.Va., will receive Arecibo’s echo from the asteroid and transmit its data back to Arecibo.

TU2 is one of an estimated 7,000 near-Earth objects, its size or larger – most have never been closely studied.

“We have good images of a couple dozen objects like this, and for about one in 10, we see something we‘ve never seen before,” said Nolan. “We really haven’t sampled the population enough to know what’s out there.”

Arecibo’s radar is vital for continuing to classify and understand such objects, said Cornell University assistant professor of astronomy Jean-Luc Margot. “Arecibo does a fantastic job at getting images, discovering the shape, spin and reflection properties of such an object . . . all these things that are important to know.”

The telescope will be trained on TU24 Jan. 27-28 and again Feb. 1-4. Goldstone’s planetary radar observed it Jan. 23-24.

About Arecibo Observatory
The Arecibo Observatory is a very sensitive radio telescope located approximately 9 miles (14 km) south-southwest from the town of Arecibo in Puerto Rico. It is operated by Cornell University under cooperative agreement with the National Science Foundation. The observatory works as the National Astronomy and Ionosphere Center (NAIC) although both names are officially used to refer to it. NAIC more properly refers to the organization that runs both the observatory and associated offices at Cornell University.
The observatory's 305 m radio telescope is the largest single-aperture telescope (cf. multiple aperture telescope) ever constructed. It carries out three major areas of research: radio astronomy, aeronomy (using both the 305 m telescope and the observatory's lidar facility), and radar astronomy observations of solar system objects. Usage of the telescope is gained by submitting proposals to the observatory, which are evaluated by an independent board of referees.
The telescope is visually distinctive and has been used in the filming of two notable motion pictures: as the villain's antenna in the James Bond movie GoldenEye and as itself in the film Contact. The telescope received additional international recognition in 1999 when it began to collect data for the SETI@home project.
The Arecibo telescope is distinguished by its enormous size: the main collecting dish is 305 m in diameter, constructed inside the depression left by a karst sinkhole. The dish is the largest curved focusing dish on Earth, giving Arecibo the largest electromagnetic-wave gathering capacity. The Arecibo telescope's dish surface is made of 38,778 perforated aluminum panels, each measuring about 1 m by 2 m (3 ft by 6 ft), supported by a mesh of steel cables.

About Asteroids
Asteroids, also called minor planets or planetoids, are a class of astronomical objects. The term asteroid is generally used to indicate a diverse group of small celestial bodies in the solar system that orbit around the Sun. 'Asteroid' (Greek for "star-like") is the most commonly used word in the English literature for minor planets, which has been the term preferred by the International Astronomical Union; some other languages prefer planetoid (Greek: "planet-like"), because it more or less describes what they are. In late August 2006, the IAU introduced the term "small solar system bodies" (SSSB), which includes most objects thus far classified as minor planets, as well as comets. At the same time they introduced the term 'dwarf planet' for the largest minor planets. This article deals specifically with the minor planets that orbit in the inner solar system (roughly up to the orbit of Jupiter). For information on other types of objects, such as comets, Trans-Neptunian objects, and centaurs, see Small solar system body. The first asteroid to be discovered, Ceres, is the largest asteroid known to date and is now classified as a dwarf planet. All others are currently classified as small solar system bodies. The vast majority of asteroids are found within the main asteroid belt, with elliptical orbits between those of Mars and Jupiter. It is thought that these asteroids are remnants of the protoplanetary disc, and in this region the accretion of planetesimals into a larger planet or planets during the formative period of the solar system was prevented by large gravitational perturbations by Jupiter. Some asteroids have moons or are found in co-orbiting pairs known as binary systems.