Subscribe free to our newsletters via your
. 24/7 Space News .




EXO WORLDS
Rare Stellar Alignment Offers Opportunity To Hunt For Planets
by Staff Writers
Baltimore MD (SPX) Jun 05, 2013


This plot shows the projected motion of the red dwarf star Proxima Centauri (green line) over the next decade, as plotted from Hubble Space Telescope observations. Because of parallax due to Earth's motion around the sun, the path appears scalloped. Because Proxima Centauri is the closest star to our sun (distance, 4.2 light-years), its angular motion across the sky is relatively fast compared to much more distant background stars. This means that in 2014 and 2016 Proxima Centauri will pass in front of two background stars that are along its path. The background image shows a wider view of the region of sky in the southern constellation Centaurus that Proxima is traversing. Credit:NASA, ESA, K. Sahu and J. Anderson (STScI), H. Bond (STScI and Pennsylvania State University), M. Dominik (University of St. Andrews), and Digitized Sky Survey (STScI/AURA/UKSTU/AAO). For a larger version of this image please go here.

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.

.


Related Links
Hubble Space Telescope
Lands Beyond Beyond - extra solar planets - news and science
Life Beyond Earth






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








EXO WORLDS
Lightest exoplanet imaged so far?
Munich, Germany (SPX) Jun 05, 2013
Although nearly a thousand exoplanets have been detected indirectly - most using the radial velocity or transit methods - and many more candidates await confirmation, only a dozen exoplanets have been directly imaged. Nine years after ESO's Very Large Telescope captured the first image of an exoplanet, the planetary companion to the brown dwarf 2M1207), the same team has caught on camera w ... read more


EXO WORLDS
NASA's GRAIL Mission Solves Mystery of Moon's Surface Gravity

Moon dust samples missing for 40 years found in Calif. warehouse

Unusual minerals in moon craters may have been delivered from space

Moon being pushed away from Earth faster than ever

EXO WORLDS
Mars Curiosity Rover Provides Strong Evidence for Flowing Water

Ten Years At Mars: New Global Views Plot History Of The Red Planet

Flowing Water Transported Sand, Rocks Along Martian Streambed

Leicester Scientist Helps Discover Ancient Streambed On Mars

EXO WORLDS
White House moves to curb 'patent trolls'

A certain level of stress is necessary

Northrop Grumman-Built Modular Space Vehicle Nears Completion of Manufacturing Phase

French government posts space counsellor in Bangalore

EXO WORLDS
Shenzhou-10 spacecraft to be launched in mid-June

Sizing Up Shenzhou 10

Rollout for Shenzhou 10

Soft Pedal for Shenzhou 10

EXO WORLDS
International trio takes shortcut to space station

Science and Maintenance for Station Crew, New Crew Members Prep for Launch

ESA Euronews: Living in space

Next destination: space

EXO WORLDS
The Future of Space Launch

Rocket Engine Maker Proton-PM to Invest in New Products

Russia Launches European Telecoms Satellite

Ariane poised to launch first 20 ton payload into orbit

EXO WORLDS
Rare Stellar Alignment Offers Opportunity To Hunt For Planets

In feat, telescope directly spots lightweight exoplanet

Scouting for Not-So-Distant Worlds

Lightest exoplanet imaged so far?

EXO WORLDS
Atom by atom, bond by bond, a chemical reaction caught in the act

Dense hydrogen in a new light

Another American High Frontier First: 3-D Manufacturing in Space

Charred micro-bunny sculpture shows promise of new material for 3-D shaping




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement