NASA Hopes Rare Stellar Alignment Will Unveil Neighboring Planets

NASA’s planet hunters are headed toward two rare opportunities in the search for neighboring worlds as Proxima Centauri, the star closest to the Sun, is locked on a trajectory that will cause it to pass in front of two other stars in coming years, according to new research led by astronomer Kailash Sahu.

Scheduled to take place in October 2014 and February 2016, researchers determined the red dwarf’s trajectory using information from the Hubble Space Telescope – the same telescope scientists plan on using during both of those months.

And while previous attempts to detect planets around Proxima Centauri have been unsuccessful, scientists believe they may be able to detect smaller terrestrial planets, should they exist, by looking for microlensing effects during the two stellar alignments.

Microlensing occurs when a foreground star passes close to Earth's line of sight to a more distant background star, causing the image of the latter to become distorted, brightened or multiplied based on the alignment between the foreground lens and the background source.

Capable of lasting anywhere from a few hours to a few days, microlensing events allow astronomers to measure the precise mass of the red dwarf and thus gain a key insight into the star’s temperature, diameter, intrinsic brightness and longevity.

The astronomers plan on achieving this by examining the images of each of the background stars to see how far the stars are offset from their actual positions in the sky. Because such offsets are the result of the star’s gravitational field warping space, the degree of them can be used to measure the star’s mass.

Ultimately, the greater the offset is, the greater the mass of Proxima Centauri.

Furthermore, should the red dwarf be carting any planets with it, the gravitational fields will produce a second small position shift.

As a result of Proxima Centauri’s proximity, the area of sky warped by its gravitation field is larger than for more distant stars, making it easier for scientists to detect a shift in apparent stellar position caused by this effect.

However, the positional shifts will be too small to be perceived by any but the most sensitive telescopes both in space and on the ground. For this reason, NASA astronomers are looking to the European Space Agency’s Gaia space telescope and the European Southern Observatory’s Very Large Telescope in Chile to make comparable estimates to Hubble’s.