June 4, 2013
Unique Opportunity To Search For Planets Around Proxima Centauri
John P. Millis, Ph.D. for redOrbit.com — Your Universe Online
Besides our own Sun, the red dwarf star Proxima Centauri is the nearest star to Earth. As such, astronomers have sought to determine if planets orbit the tiny object. But because of its low brightness, and other issues, previous attempts to find planets using traditional methods have failed.But researchers have now determined that two unique opportunities -- one in October 2014, another in February 2016 -- will allow scientists using the Hubble Space Telescope to make the most sensitive measurements yet. At those two periods, Proxima will pass directly in front of more distant stars. When this happens, scientists can measure what is known as the microlensing effect from Proxima Centauri. "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 Telescope Science Institute in Baltimore, Md.
Essentially, because of the mass of Proxima Centauri, the light from the star behind it will be bent. Since astronomers know where the background star should be, they can now measure how much the light is being deflected. From this they can more accurately determine the mass of Proxima Centauri.
If any planets were present, however, there would also be a secondary lensing effect, which would also be a function of the planetary mass. This planetary microlensing effect would be small, as the planets themselves are likely of low mass. But because Proxima is so close, the effect could still be detectible from Earth. Even so, only the most powerful optical telescopes in the world will have a chance of measuring the distortions.