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More to the North Star Than Meets the Eye
__roo writes "By stretching the capabilities of NASA's Hubble Space Telescope to the limit, astronomers have photographed the close companion of Polaris for the first time. This sequence of images shows that the North Star, Polaris is really a triple star system. 'The star we observed is so close to Polaris that we needed every available bit of Hubble's resolution to see it'" said astronomer Nancy Evans of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts."
The Hubble already has a repalcement in the works. It is called The James Webb Space Telescope and is scheduled to go up in 2013. More about the JWST
According to google calculator:
2 000 000 000 miles = 21.5155818 Astronomical Units
which puts it just inside the closest approach of Saturn, but well outside Jupiter's orbit.
From the article: "The companion proved to be less than two-tenths of an arcsecond from Polaris... At the system's distance of 430 light-years, that translates into a separation of about 2 billion miles."
I did a little googling, and found that Neptune's orbit is just over 2 billion miles from the Sun. So for reference, Hubble has directly imaged two distant objects that could fit inside our own solar system.
I think they could have gotten more "Oomph!" from their press release if they'd mentioned this fact. Also, they may have wanted to measure the distance in a standard publicity unit, such as roundtrip NY-LA distances ("A little over 350,000 round-trips from New York to Los Angeles").
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
It's a triple star system if they're all rotating around a common centre of gravity, even if PolarisB seems to be quite an outsider (although on the scale they're showing it is probably still at a distance similar to a Kuiper belt object (rough guess) whilst this Ab star is at Saturn distance from A.
I suppose it is possible that Ab is behind A and thus appears further away, but I'm sure they've done their maths and checked it over a lot before releasing the PR.
Adaptive optics systems are necessarily ground-based. The actuators and the lenses required are too bulky and heavy to be lugged into orbit. The atmosphere absorbs much incoming radiation. (Thank god, or we'd all literally be toast.) Scientists interested in the ultraviolet have to use space-based telescopes. Hence, the Hubble replacement does not focus on the visible because AO can take care of that from Earth, since we can build arbitrarily large arrays.
A NYC lawyer blogs. http://www.chuangblog.com/
Your first comment is true in the general 3-body problem, but certain cases are actually stable over a long period of time. Namely, when two of the bodies are in a very tight orbit which is not significantly perturbed by the 3rd body.
So, the system approximates a stable two body system.
Another similar case is 4 stars, where there are two close pairs in orbit around each other. This idea can be extrapolated to any number of stars as long as each pair is not significantly perturbed by its non-pair neighbors.
HCG 50a = 2MASX J11170638+5455016
11h17m06.4s +54d55m02s
Yes, someone always posts this when the death of the hubble is brought up, but what they never do is pay attention that the JWST can't see all that Hubble sees. They're built to look at different parts of the spectrum (yes, there is overlap), so one will never actually replace the capabilites of the other. They would however complement eachother's abilities.
- AMW