Space

June 3, 2013

NASA’s Hubble will use rare stellar alignment to hunt for planets

NASA’s Hubble Space Telescope will have two opportunities in the next few years to hunt for Earth-sized planets around the red dwarf Proxima Centauri.

The opportunities will occur in October 2014 and February 2016 when Proxima Centauri, the star nearest to our sun, passes in front of two other stars. Astronomers plotted Proxima Centauri’s precise path in the heavens and predicted the two close encounters using data from Hubble.

“Proxima Centauri’s trajectory offers a most interesting opportunity because of its extremely close passage to the two stars,” said Kailash Sahu, an astronomer with the Space Science Telescope Institute in Baltimore, Md. Sahu leads a team of scientists whose work he presented Monday at the 222nd meeting of American Astronomical Society in Indianapolis.

Red dwarfs are the most common class of stars in our Milky Way galaxy. Any such star ever born is still shining today. There are about 10 red dwarfs for every star like our sun. Red dwarfs are less massive than other stars. Because lower-mass stars tend to have smaller planets, red dwarfs are ideal places to go hunting for Earth-sized planets.

Previous attempts to detect planets around Proxima Centauri have not been successful. But astronomers believe they may be able to detect smaller terrestrial planets, if they exist, by looking for microlensing effects during the two rare stellar alignments.

Microlensing occurs when a foreground star passes close to our line of sight to a more distant background star. These images of the background star may be distorted, brightened and multiplied depending on the alignment between the foreground lens and the background source.

These microlensing events, ranging from a few hours to a few days in duration, will enable astronomers to measure precisely the mass of this isolated red dwarf. Getting a precise determination of mass is critical to understanding a star’s temperature, diameter, intrinsic brightness and longevity.

Astronomers will measure the mass by examining images of each of the background stars to see how far the stars are offset from their real positions in the sky. The offsets are the result of Proxima Centauri’s gravitational field warping space. The degree of offset can be used to measure Proxima Centauri’s mass. The greater the offset, the greater the mass of Proxima Centauri. If the red dwarf has any planets, their gravitational fields will produce a second small position shift.

Because Proxima Centauri is so close to Earth, the area of sky warped by its gravitation field is larger than for more distant stars. This makes it easier to look for shifts in apparent stellar position caused by this effect. However, the position shifts will be too small to be perceived by any but the most sensitive telescopes in space and on the ground. The European Space Agency’s Gaia space telescope and the European Southern Observatory’s Very Large Telescope on Mt. Cerro Paranal in Chile may be able to make measurements comparable to Hubble’s.

To identify possible alignment events, Sahu’s team searched a catalog of 5,000 stars with a high rate of angular motion across the sky and singled out Proxima Centauri. It crosses a section of sky with the apparent width of the full moon as observed from Earth every 600 years.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines September 22, 2014

News: U.S., Canadian jets intercept Russian planes -  The U.S. this week intercepted a half dozen Russian planes that got too close to U.S. airspace near Alaska, while Canadian planes intercepted two Russian bombers, NORAD said Sept. 20. Odierno: More troops in Afghanistan may get pink slips - More soldiers could learn while in Afghanistan that they...
 
 

News Briefs September 22, 2014

U.S. general: Arab nations needed in Iraq, Syria The top U.S. military officer says Arab countries need to take a more direct role in the U.S. military mission in Iraq before it can be credible and sustainable. Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, said Sept. 21 that President Barack Obama...
 
 
boeing-ethiopia

Boeing, Ethiopian Airlines announce order for 20 737 MAX 8s

  Boeing and Ethiopian Airlines Sept. 20 announced an order for 20 737 MAX 8s. The order, previously unidentified on the Boeing Orders & Deliveries website, is worth more than $2.1 billion at list prices and also inclu...
 

 
NASA image

NASA’s newest Mars mission spacecraft enters orbit around red planet

NASA image This animation depicts NASAís Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft orbiting Mars. NASA’s Mars Atmosphere and Volatile Evolution spacecraft successfully entered Mars’ orbit at 10:24 p...
 
 
nasa-mars-website

NASA launches new citizen science website

Opens challenge to participate in future Mars missions NASA announced Sept. 20 the opening of registration for its Mars Balance Mass Challenge and the launch of its new website, NASA Solve, at the World Maker Faire in New York....
 
 
airbus-collaboration

Airbus Group, Aerion announce technology collaboration

Airbus Group and Aerion Corporation have agreed to collaborate on technologies associated with the future of high-performance flight. To further their mutual objectives, both companies will exchange knowledge and capabilities i...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>