Alpha Centauri has been in the news a bit lately, after astronomers discovered a potentially habitable planet in the Goldilocks zone around the system’s smallest star, Proxima Centauri. But Proxima Centauri isn’t the only hotness in its neighborhood. Now a just-announced collaboration called Project Blue has been founded to launch a lightweight, low-overhead space telescope, to look at the two largest stars in that system, Alpha Centauri A and B. The idea is that the Project Blue telescope would directly image any orbiting planets within the stars’ habitable zones.
Project Blue has a cast of scientific luminaries including Jon Morse, head of the BoldlyGo institute and former head of astrophysics at NASA. Other universities and groups include SETI, Mission Centaur, and UMass at Lowell, with a whole panel of advisers and others doubtless soon to follow.
In contrast to other telescopes like Hubble and Kepler, small, quick, and cheap are the buzzwords for this project. The telescope is supposed to have an 18″ mirror — for reference, Hubble’s double that, but Hubble is a much more “generalist” instrument. This telescope would just look at Alpha Centauri, so it doesn’t need all the capability of the Great Observatory-class telescopes, which is good news for costs. Morse is shooting for a budget of $50 million to get the telescope into orbit, but hoping he can do it for half that.
The privately funded mission also aims to launch the comparatively pint-sized telescope into orbit before the end of the decade — a blink of the eye, when it comes to space telescopes and time. While Project Blue is in its planning stages, the consortium is revving up their funding efforts. If they manage to get successfully funded, they hope to launch the refrigerator-sized telescope into orbit by 2019.
UMass is involved with Project Blue because they’ve been doing such groundbreaking work on stellar coronography. If directly imaging an exoplanet next to its star is like imaging a firefly next to a lighthouse, then the Project Blue telescope needs to very carefully mask out the lighthouse.
Scientists don’t know yet whether Alpha Centauri has any planets. But data from Kepler suggests that every star in our galaxy has at least one planet orbiting it. We’ve even found evidence that some binary star pairs have planets. So it stands to reason that Alpha Centauri may have a planet or planets to observe. Hopefully there will be one with liquid water and an atmosphere. It would show up as a pale blue dot just a few pixels across, just like our own blue marble next to our own quivering drop of plasma. But the color of an exoplanet tells us a lot about its composition and atmosphere. Watching it through time reveals details about the orbital characteristics of the planets the consortium hopes to find.
The stars of the Alpha Centauri system also afford a solid chance to image Goldilocks-zone exoplanets because of their size. Proxima b is in Proxima Centauri’s habitable zone, but because Proxima Centauri is a red dwarf, that zone is too close to cleanly separate Proxima b from the light shed by its parent star. Alpha Centauri A and B are both significantly larger, so their habitable zones will be further out — hopefully far enough to allow Project Blue a chance for successful direct visible-spectrum imaging of exoplanets in the system.