Habitable planet around Proxima

No this is not a discovery announcement, so don’t stress. Instead Greg Laughlin has posted over on Systemic a discussion of what a positive detection of a habitable planet around a red dwarf star would require of current telescopic facilities. Proxima Centauri would be a surprisingly easy target and a logical one, since it is so close to our Sun allowing first class data to be gathered. Best of all it’s only 4.22 ly away – just 267,000 AU. Depressingly our fastest probes currently only do about 3 – 4 AU a year, so Proxima is still a long, long way off. Happily it’s also gradually getting closer, so by the year 27,000 it will be about 3.2 ly away. A few millennia shaved off the trip time.

In reality no one advocates a mere ~ 5 AU a year. The fastest seriously proposed vehicle is the Thousand AU (TAU) probe which can do a cracking 20 AU/yr. That’s a 10,000 year trip to Proxima at its closest. Of course there have been less serious designs for probes, the most detailed being the British Interplanetary Society’s “Daedalus”, which can do a mind boggling 0.122 lightspeed – almost 37,000 km/s – which puts Proxima a mere 35 years away, neglecting braking at the other end. With a magnetic-sail as a propellant-less brake a “Daedalus” probe could slow-down into orbit around Proxima, adding maybe 10 years to the trip time. A magnetic-sail would also allow the probe to visit all the planets in the system (Laughlin estimates anywhere between 2 and 5 terrestrial planets, as Jovian planets have already been ruled out.) Thus results from an orbital survey of a habitable planet could be beamed back to Earth some 50 years after launch.