Asteroid to make closest approach since 1975
January 30, 2012 by Jason Major, Universe Today
Asteroid 433 Eros as seen by NASA's NEAR spacecraft on Feb. 29, 2000. Credit: NASA/JPL/JHUAPL
On Tuesday, January 31, asteroid 433 Eros will come closer to Earth than it has in 37 years, traveling across the night sky in the constellations Leo, Sextans and Hydra. At its closest pass of 16.6 million miles (26.7 million km) the relatively bright 21-mile (34-km) -wide asteroid will be visible with even modest backyard telescopes, approaching magnitude 8, possibly even 7. It hasn’t come this close since 1975, and won’t do so again until 2056!
433 Eros is an S-type asteroid, signifying a composition of magnesium silicates and iron. S-types make up about 17 percent of known asteroids and are some of the brightest, with albedos (reflectivity) in the range of 0.10 – 0.22. S-type asteroids are most common in the inner asteroid belt and, as in the case of Eros, can even pass within the orbit of Mars.
Occasionally Eros’ orbit brings it close enough to Earth that it can be spotted with amateur telescopes. 2012 will be one of those times.
Eros was discovered on August 13, 1898, by astronomers Carl Gustav Witt in Berlin and Auguste Charlois in Nice. When Eros’ orbit was calculated it was seen to be an elongated oval that brought it within the orbit of Mars. This allowed for good observations of the bright asteroid, and eventually led to more accurate estimates of the distance from Earth to the Sun.
Orbit of 433 Eros for Jan. 31, 2012
In February 2000 NASA’s NEAR Shoemaker spacecraft approached Eros, established orbit and made a soft landing on its surface, the first mission ever to do so. While in orbit NEAR took over 160,000 images of Eros’ surface, identifying over 100,000 craters, a million house-sized boulders (give or take a few) and helped researchers conclude that the cashew-shaped Eros is a solid object rather than a “rubble pile” held together by gravity.View NEAR images of Eros’ surface.
Studying pristine objects like Eros gives insight into the earliest days of our solar system, and also allows scientists to better understand asteroid compositions… which is invaluable information when deciding how best to avoid any potential future impacts.
Although Eros will be making a “close” approach to Earth on Jan. 31/Feb. 1, there is no danger of a collision. It will still remain at a very respectable distance of about 16.6 million miles (26.7 million km), or 0.178 AU. This is over 80 times the distance of the much smaller 2005 YU55, which safely passed within a lunar orbit radius on November 8, 2011.
If you do want to try viewing 433 Eros as it passes, you can find a diagram charting its path from Sky and Telescope here. According to the Sydney Observatory’s website “the coordinates on 31 January (from the BAA 2012 Handbook) are 10 hours 33 minutes 19.0 seconds RA and -4° 48’ 23” declination. On 10 February the RA is 10 hours 20 minutes 27.6 seconds and the declination is -14° 38’ 49 seconds.”
Also there’s an updated chart on Heavens Above showing Eros’ current position.
Eros should remain visible up until Feb. 10.
Source: Universe Today
-
From lemons to lemonade: Reaction uses carbon dioxide to make carbon-based semiconductor,
32 comments
-
Thioridazine kills cancer stem cells in human while avoiding toxic side-effects of conventional cancer treatments,
3 comments
-
SpaceX private rocket blasts off for space station (Update),
42 comments
-
Climate scientists say they have solved riddle of rising sea,
31 comments
-
SpaceX capsule has 'new car' smell, astronauts say (Update),
4 comments
-
Distance of planets from stars and revolution
8 hours ago
-
revamping general concept and cosmological principle
May 25, 2012
-
Transiting Exoplanet Light Curve
May 25, 2012
-
Math behind Theoretical Physics
May 24, 2012
-
Do we know whats at the center of galaxies yet?
May 23, 2012
-
Structure of the Milky Way?
May 20, 2012
- More from Physics Forums - General Astronomy
More news stories
Land and sea species differ in climate change response: study
(Phys.org) -- Marine and terrestrial species will likely differ in their responses to climate warming, new research by Simon Fraser University and Australia’s University of Tasmania has found.
6 hours ago |
3.8 / 5 (4) |
5
|
Yale study concludes public apathy over climate change unrelated to science literacy
Are members of the public divided about climate change because they don't understand the science behind it? If Americans knew more basic science and were more proficient in technical reasoning, would public consensus match ...
8 hours ago |
4.8 / 5 (5) |
20
|
10 million years needed to recover from mass extinction
It took some 10 million years for Earth to recover from the greatest mass extinction of all time, latest research has revealed.
Space & Earth / Earth Sciences
8 hours ago |
4 / 5 (4) |
1
|
Sophisticated simulations predict future warming
The chances of our planet being hit by a global warming of 3 degrees Celsius by 2050 is as likely as it being hit by an increase of 1.4 degrees, new research shows. Presented in the journal Nature Geoscience, the British study ...
Space & Earth / Earth Sciences
May 22, 2012 |
4.1 / 5 (10) |
51
Aliens don't want to eat us, says former SETI director
Alien life probably isn’t interested in having us for dinner, enslaving us or laying eggs in our bellies, according to a recent statement by former SETI director Jill Tarter.
Space & Earth / Space Exploration
May 25, 2012 |
4.4 / 5 (15) |
41
Stunning image of smallest possible five-ringed structure
Scientists have created and imaged the smallest possible five-ringed structure – about 100,000 times thinner than a human hair – and you'll probably recognise its shape.
'Unzipped' carbon nanotubes could help energize fuel cells, batteries
Multi-walled carbon nanotubes riddled with defects and impurities on the outside could replace some of the expensive platinum catalysts used in fuel cells and metal-air batteries, according to scientists at ...
Change in developmental timing was crucial in the evolutionary shift from dinosaurs to birds: study
At first glance, it's hard to see how a common house sparrow and a Tyrannosaurus Rex might have anything in common. After all, one is a bird that weighs less than an ounce, and the other is a dinosaur that ...
Computer model used to pinpoint prime materials for efficient carbon capture
When power plants begin capturing their carbon emissions to reduce greenhouse gases – and to most in the electric power industry, it's a question of when, not if – it will be an expensive undertaking.
T cells 'hunt' parasites like animal predators seek prey, study shows
By pairing an intimate knowledge of immune-system function with a deep understanding of statistical physics, a cross-disciplinary team at the University of Pennsylvania has arrived at a surprising finding: T cells use a movement ...
Scientists develop ultra-sensitive test that detects diseases in their earliest stages
Scientists have developed an ultra-sensitive test that should enable them to detect signs of a disease in its earliest stages, in research published today in the journal Nature Materials.
Jan 30, 2012
Rank: 3 / 5 (1)
It would have been interesting to try nuking it and/or hitting it with an impactor at some point shortly after flyby to see if that is feasible and produces any significant result at all. (I think for such an experiment we could waive the "no nukes in space" law if all countries contribute/consent)
Jan 30, 2012
Rank: 4 / 5 (2)
Jan 30, 2012
Rank: 5 / 5 (2)
But you can get pictures like these
http://near.jhuapl.edu/
Which is from an altitude of down to 120 meters (shot during the descent).
If I read the mission profile correctly then the rendevouz was also at about 2AU distance (which means that there is only a quarter of the light available than on Earth - consequently they needed to up the exposition time to get better pictures.)
Jan 30, 2012
Rank: 3 / 5 (1)
C'mon, that's only 2 f-stops and the albedo is high.
Jan 30, 2012
Rank: 5 / 5 (2)
That's a third less than Earth (0.36). So total light is 16% of what you get from Earth (if they approached with the sun directly at their backs ...but from the pics it looks like they approached at an angle to the sun)
CCDs are more attuned to the infrared spectrum (I'm not at all sure the pictures on the NASA website are visible light pics). Albedo is over the entire range of radiation...Eros probably has a different spectral distribution from Earth, so the number might be even lower for the radiation the CCD is sensitive to (or it might be higher).
Add to that that they wanted the pics to be sent before the craft hit (because they couldn't be sure that it would continue working afterwards)...and the number of pics you can send becomes severly limited during the last stages of 'landing' - because the bandwith over interplanetary distances is rather low.