Best image of Alpha Centauri A and B | Hacker News Reader

Best image of Alpha Centauri A and B

sciencebulletin.org

53 pointsupen18 comments

> They orbit a common centre of gravity once every 80 years, with a minimum distance of about 11 times the distance between the Earth and the Sun.

A.K.A an Astronomical Unit: https://en.wikipedia.org/wiki/Astronomical_unit

Both stars are close to our sun in size.

The visible area in square-arc-seconds (and thus the brightness) of Beta as seen from Alpha (and vice versa) should be about (1/11)^2 = 0.8 % or about the same as an overcast day on Earth.

I think I read that stable planet orbits would be impossible, but I suppose a planet could still have a stable orbit around one of the Lagrange points.

Then it should have each star at equal distance, at 90 deg angle, right? If so, it would have 4 phases of daylight - night, Alpha, both suns and Beta.

Huh; Saturn is about 10 AU from the sun, so that would be like having a second star just past the orbit of Saturn.

https://en.wikipedia.org/wiki/Solar_System

So is it always changing whixh one of these is closest to us?

The Barracuda filter at the hotel I'm staying at is blocking this site:

> The link you are accessing has been blocked by the Barracuda Web Filter because it contains spyware. The name of the spyware is: Spyware.Exploit.BRTS.sciencebulletin.org

A quick Google turned up nothing -- why is sciencebulletin.org considered dangerous?

Probably the usual, they were either compromised to serve up malware or their mail server was compromised to serve up phishing emails and the like and the blocklist hasn't been updated since when they fixed the issue.

To the site owner, contacting Barracuda is sufficient to get you off the list if you're clean.

Here's a mirror: http://webcache.googleusercontent.com/search?sclient=psy-ab&...

Is the angular diameter of the stars in this picture still tiny, or are scientists actually resolving discs now?

Still blurry, but astronomers have resolved the surface of a few stars:

Example: http://apod.nasa.gov/apod/ap981011.html

List: https://en.wikipedia.org/wiki/List_of_stars_with_resolved_im...

That's very cool. Thanks

We can measure the diameter of Proxima Centauri directly, wiki says:

https://en.wikipedia.org/wiki/Proxima_Centauri

How does Proxima Centauri play into this? I am assuming it isn't a trinary star system, but they mention it being (roughly) the same distance away in the same direction.

Also, are there planets in the binary Alpha Centauri system? Do they orbit the common center of mass that the two stars orbit?

We will get a better picture with the James Webb telescope?

Just a lens flare

So this is an interesting point - the distinctive flare of astronomical photos is caused by light diffracting around the mirror supports within the telescope. We know the proportions of these, and could apply a transform that approximately reverses the effect. So why is it never done?

I suppose the lens flare variant is prettier, and more star-like, but it would be interesting to see the plain variant occasionally.

I think it's because the deconvolution is a bit tricky (with a few different "knobs" to turn somewhat arbitrarily in the process), and can in some ways be expected to add in more artifacts than it is subtracting.

When you use the phrase "distinct lens flare", it actually makes me wonder if the lens flare is truely distinct in the manner that each telescope has a different lens flare "signature".

I wonder if it possible to identify telescopes used to take images from their lens flares to any degree if certainty, like profiling on a bullet can sometimes identify the type of gun it was fired from?

https://en.wikipedia.org/wiki/Diffraction_spike

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