The search for habitable exoplanets in Alpha Centauri

[alberto91]

In October 2012, astronomers announced the discovery of an exoplanet orbiting the star Alpha Centauri B. However, three years later, they concluded that it probably doesn’t exist. In 2013, astronomers also detected another possible exoplanet, but it hasn’t been confirmed yet. As of today, no exoplanets have been discovered around Alpha Centauri A or B.

There are several ongoing projects to search for habitable exoplanets in Alpha Centauri:

The Expresso spectrograph, which started operating in October 2018, is able to detect radial velocities of less than 10 cm/s.

Another promising instrument is called NEAR, which stands for Near Earths in the AlphaCen Region. NEAR is a thermal infrared coronagraph that blocks most of the light coming from Alpha Centauri in order to resolve possible exoplanets around the star. This coronagraph can detect exoplanets 2 times the radius of the Earth.

Project Blue is another interesting project that might help us discover the closest Earth-like planet. It is a small space telescope with a coronagraph that will directly image the habitable zones of the Alpha Centauri system. The telescope will be able to detect exoplanets between 0.5 and 1.5 times the radius of the Earth. The launch of the telescope is expected to take place in 2023.

NASA is also working on a space telescope with coronagraph called ACEND, which stands for Alpha Centauri Direct Imager.

Breakthrough Initiatives is now working on a space telescope called TOLIBOY that will use astrometry to map the motion of the Alpha Centauri stars and search for a perturbation in the positions. The telescope is expected to be launched in 2021.

Source: Do you think all the agencies and companies should join efforts and build just 1 big space coronagraph, or, as they seem to be doing now, work on different ones?

 

[stefan r]

...Do you think all the agencies and companies should join efforts and build just 1 big space coronagraph, or, as they seem to be doing now, work on different ones?

They are not redundant systems. They are collecting different types of data. Evidence is better if it is verified by more than one method. Aside from that, the instruments can be used for multiple purposes.

A planet around Alpha Centuari is not actionable information. If you build a spaceship that can go there and get close pictures the debris clouds would be very interesting. The presence of a planet does not change the fact that no such ship exists.

The ability to collect data about an Earth size planet around the closest star system is a good benchmark. It is also just a target. As soon as they demonstrate infrared resolution around Alpha-Centuari they should move the goal posts out by a factor of 10. Maybe find planets around Vega etc. We should also look for Mercury size planets and moons. Alpha Centuari has stable orbits for Kuiper belt objects so we can keep going with higher precision measurements.

Contrast with European Extremely Large Telescope, Giant Magellan Telescope, and 30 Meter Telescope. We have 3 huge telescopes each use visible light. They were all partially built and then ran out of funds. To some extent 30m telescope and EELT can look at different parts of the sky. However, it would have been nice to see images a few years earlier. My impression is that the problem was entirely political and somewhat childish.

 

[Vanadium 50]

TMT, so far as I know, has not run out of money. It was blocked by local protests. Construction is supposed to resume this year.

(Thanks to berkeman for pointing out the typos)