2004 BL86 Passes By

Asteroid 2004 BL86 is not small, it is large enough for astronomers to take notice as it passed near the earth yesterday at a close, but safe distance of 745,000 miles. Numerous telescopes were trained on this object as it passed by, including a deep space radar at Goldstone that confirmed that the asteroid is about 1,100 feet in diameter. They did get a surprise as well, 2004 BL86 has a small moon.

Close approach was earlier in the day, thus it was some hours after that I was able to photograph the asteroid from Hawaii. The most difficult part in taking the photo is locating the object. An asteroid this close by will move across the sky very quickly. To locate the asteroid I used a high precision ephemeris generated by the JPL Horizons Database with time intervals of every half hour. This was necessary as the asteroid was moving several degrees each hour. If I used coordinates even an hour off it would have been out of the frame. It took half an hour of hunting, comparing frames taken a couple minutes apart.

Below is the streak created as the asteroid moves over the course of an eight minute exposure…

2004 BL86
Asteroid 2004 BL86 just after close approach on January 26, 2015

Asteroid 1998 QE2 to Sail Past Earth

JPL press release

On May 31, 2013, asteroid 1998 QE2 will sail serenely past Earth, getting no closer than about 3.6 million miles (5.8 million kilometers), or about 15 times the distance between Earth and the moon. And while QE2 is not of much interest to those astronomers and scientists on the lookout for hazardous asteroids, it is of interest to those who dabble in radar astronomy and have a 230-foot (70-meter) — or larger — radar telescope at their disposal.

Asteroid 1998 QE2 Orbit
The orbit for asteroid 1998 QE2 earth approach on 31 May 2013. Image credit: NASA/JPL-Caltech
“Asteroid 1998 QE2 will be an outstanding radar imaging target at Goldstone and Arecibo and we expect to obtain a series of high-resolution images that could reveal a wealth of surface features,” said radar astronomer Lance Benner, the principal investigator for the Goldstone radar observations from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Whenever an asteroid approaches this closely, it provides an important scientific opportunity to study it in detail to understand its size, shape, rotation, surface features, and what they can tell us about its origin. We will also use new radar measurements of the asteroid’s distance and velocity to improve our calculation of its orbit and compute its motion farther into the future than we could otherwise.”

The closest approach of the asteroid occurs on May 31 at 1:59 p.m. Pacific (4:59 p.m. Eastern / 20:59 UTC). This is the closest approach the asteroid will make to Earth for at least the next two centuries. Asteroid 1998 QE2 was discovered on Aug. 19, 1998, by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program near Socorro, New Mexico.

The asteroid, which is believed to be about 1.7 miles (2.7 kilometers) or nine Queen Elizabeth 2 ship-lengths in size, is not named after that 12-decked, transatlantic-crossing flagship for the Cunard Line. Instead, the name is assigned by the NASA-supported Minor Planet Center in Cambridge, Mass., which gives each newly discovered asteroid a provisional designation starting with the year of first detection, along with an alphanumeric code indicating the half-month it was discovered, and the sequence within that half-month.

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Asteroid Flyby

We are going to get buzzed Tuesday. A reasonably large asteroid will pass quite close to the Earth, well inside lunar orbit. Asteroid 2005 YU55 will pass 325,000 km (202,000 mi) from the Earth. This is a good sized object, about 400m (1300ft) in diameter, large enough to create significant damage if it were to collide. We do know that the object will safely miss, this time. It is an object to track carefully. Data from this encounter and a future encounter with Venus in 2029 will set YU55 up for another encounter with Earth in 2041. Again we believe it will miss, but it will be close.

Keck 2 will be observing YU55 using adaptive optics and NIRC2 in an attempt to get high resolution imagery of the asteroid. It is quite convenient that this interesting asteroid is passing close to Earth, it will be in easy reach of our best astronomical instrumentation. I suspect I will be spending a little time in Keck 2 remote operations Tuesday night to get a look for myself.

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