The major specific I recall is that they want to build a telescope sized like a fridge with a mirror 45-50 centimeters across. On top of that, they did specify it would be imaging in the visible light.....I suppose the question is, with essentially unlimited viewing time (the advantage of a private 'scope versus Hubble or Webb) and apparently a handful of 21st-Century tricks, can a telescope only half-a-meter wide indeed image something around either Alpha Centauri A and B?
An Earth-sized (12700 km diameter) planet around Alpha Centauri A (4.37 light-years) is 3e-10 radians across. To resolve that with 550 nm (green) light, you'd need an aperture 2.2 km in diameter. That will make the planet fill one pixel. This is obviously not the way to go.
A 50cm mirror won't resolve a planet, but can easily treat it as a point source. I did the math a while ago, and each pixel was quite smaller than an AU. So as point source you could do direct imaging. Yes, you won't resolve a continent, but any spectral analysis could be done, and it's apparent movement could be done. Even the doppler shift taken. And if you have two years of observations you could do a very good orbit determination.
1 AU at 4.3 light years is 3.7 microradians. A 50 cm aperture with 550 nm light will resolve two peaks 1.3 microradians apart. You can theoretically resolve the sun and a little dot next to it.The problem is that the Sun (3.8e26 watts) is a couple billion times brighter than, say, the Earth (1.7e17). The ratio is better is the visible band, but it's still large. The sensor itself has a dynamic range limitation of a few thousand to one, but this can be worked around. The tricky bit is that the optical system itself has dynamic range limitations. Apparently these folks have figured out how to reject most of the light from Alpha Centauri A and B so that their telescope can see a potential planet. I'm sure that's possible, but I haven't seen an explanation of how.
Keeping an eye out on how Project Blue's kickstarter's doing. Not wholly promising: only about 8% funded with 29 days to go. Possibly still a shot, but if this doesn't work they might need to take a more academic route with funding from agencies.
Among the names formally approved by the WGSN are Proxima Centauri (for the nearest star to the Sun and host star of the nearest known exoplanet), Rigil Kentaurus (the ancient name for Alpha Centauri and names for dozens of bright stars commonly used for astronavigation. Among the stars with newly approved names that have recently been reported to host extrasolar planet candidates are: Algieba (Gamma1 Leonis), Hamal (Alpha Arietis), and Muscida (Omicron Ursae Majoris).
Alpha Centauri is now officially called Rigil Kentaurus.QuoteAmong the names formally approved by the WGSN are Proxima Centauri (for the nearest star to the Sun and host star of the nearest known exoplanet), Rigil Kentaurus (the ancient name for Alpha Centauri and names for dozens of bright stars commonly used for astronavigation. Among the stars with newly approved names that have recently been reported to host extrasolar planet candidates are: Algieba (Gamma1 Leonis), Hamal (Alpha Arietis), and Muscida (Omicron Ursae Majoris).http://astronomynow.com/2016/11/24/international-astronomical-union-formally-approves-227-star-names/
Ironically Proxima Centauri keeps the same name. It would have made more sense to renamed Alpha Centauri to Rigil Centauri likewise.
Personally, thanks to Sid Meier, I think of A-Cent A as 'Apollo' and A-Cent B as 'Hercules'. I can't personally foresee any point in the future when A-Cent B isn't 'Proxima', no matter what the various governing bodies say.
Alpha Centauri is now officially called Rigil Kentaurus.
I'm not sure why IAU set up a working group to start giving proper names to stars (in most cases, just making traditional names official). Maybe it is a reaction to all kinds of 'name a star for a fee' schemes.
Quote from: Star One on 11/24/2016 07:30 pmAlpha Centauri is now officially called Rigil Kentaurus.Not quite. The IAU Working Group on Star Names approved the name Rigil Kentaurus for Alpha Centauri A. It had previously approved the name Proxima Centauri for Alpha Centauri C. It has yet to approve a name for Alpha Centauri B. Both the bulletins announcing the approvals and the IAU's Catalog of Star Names specifically specifies the letters in these two cases.The WGSN only names individual stars, whether or not they are part of a multiple star system. It will get round to naming the other components as some future date (it made an exception for Proxima Centauri as the star was just about to hit the headlines due to the discovery of the orbiting planet) and might later consider naming multiple star systems. Note that the IAU does not regard 'Alpha Centauri' as a name but as a designation.Quote from: as58 on 11/25/2016 05:51 amI'm not sure why IAU set up a working group to start giving proper names to stars (in most cases, just making traditional names official). Maybe it is a reaction to all kinds of 'name a star for a fee' schemes.Partly. But it was also a result of the NameExoWorlds process where the public was invited to name exoplanets and their host stars where the latter didn't already have a name. They didn't want to approve a star name that was already the name of a star and realised that there was no recognised list of such names. Also, it's an opportunity for public outreach once the more famous stars have been dealt with and a way of being more inclusive in regard to other cultures.
Thank you for that. Why didn't they name all three stars in the system at once as it seems illogical not to do so? Also what is likely to be the name for Alpha Centauri B?