At about 4.3 light years away, Alpha Centauri is the nearest star system to the Earth. There are three stars in the system: Alpha Centauri A, Alpha Centauri B, and Proxima Centauri. The system became a hot topic last year when astronomers discovered an Earth-like planet called Proxima b orbiting Proxima Centauri. The other two – Alpha Centauri A and B – are a binary pair that orbit each other every 79 years.

ESO Breakthrough Initiatives Alpha Centauri
Image Credit: Ryan Wick / Flickr

Looking for habitable planets in the Alpha Centauri system

Astronomers believe that there could be more planets besides Proxima b in the star system that are in the “Goldilocks zone.” Planets in the Goldilocks zone have just right temperature for liquid water to exist on their surface. Liquid water is a necessary ingredient for life as we know it. Now the European Southern Observatory (ESO) has signed an agreement with the Breakthrough Initiatives to hunt for planets in our neighboring star system.

Breakthrough Initiatives is a program backed by Stephen Hawking and Russian billionaire Yuri Milner to look for signs of life throughout the Universe. The ESO’s Very Large Telescope in Chile would be modified to make it capable of looking closely and more effectively at planets in the nearest star system to Earth. Breakthrough Initiatives would fund the modification.

The upgrade could take up to three years. The VLT’s VISIR instrument would be modified. VISIR observes objects in the mid-infrared light that can’t be seen, but is associated with heat. Astronomers observe exoplanets in mid-infrared because it can reduce the huge “gap” in the brightness of the planet and its host star, preventing the starlight from overpowering the faint light of nearby planets. VISIR will need modifications because the stars are still extremely bright in mid-infrared.

Sending tiny probes to the neighboring system

Breakthrough Initiatives has a special interest in the Alpha Centauri system. Under the mission Breakthrough Starshot, they plan to send thousands of tiny probes to planets in the system to study the possibility of life there. The probes would weigh just a few grams and would be the size of a postage stamp. They will be equipped with a variety of instrumentation including a camera, communications equipment, and a nuclear battery.

The mission will be based on technologies that are yet to be developed. Each of the tiny probes would be attached to a solar sail. Photons from a powerful laser on the ground would accelerate the speed of these probes to 20% of the speed of light. It means the probes would take approximately 20 years to travel 4.3 light years. However, the Starshot initiative is unlikely to get off the ground for another 30-40 years.

ESO says its modified VISIR instrument would start taking a close look at the neighboring system by 2019.

Photo by Ryan Wick