Rare Stellar Alignment Offers Opportunity To Hunt For Planets

[jakeXT]

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.

http://www.nasa.gov/mission_pages/hubble/science/proxima-centauri.html

[longship]

1. Proxima Centauri has low mass, even as a red dwarf.

It is only about 1/8 the mass of the sun.

It is also a "flare star", common among red dwarf stars. But that means Proxima has these relatively large flare outbursts which would be a hazard to any planet that happened to be in its Goldilocks zone. That zone would be close to Proxima because of its low mass.

On top of all that, planets of red dwarfs in the Goldilocks zone will more likely be tidally locked, meaning that one side of the planet will always face the star and one side always face away, just like the moon which is tidally locked to Earth.

But the advantage with red dwarfs is that using almost any of the methods for detecting planets, finding an Earth-sized planet is proportionally easier. Also, there are a fuck of a lot of them relatively nearby, although their dimness makes this less an advantage.