Viewing extrasolar planets

Viewing extrasolar planets

Jan 01, 2019 / By : / Category : 老域名购买

As our ability to study other stars has improved, the signs of planets orbiting them have increased. We can directly observe planet-forming disks and the indications of planets carried by the light of the star they're orbiting. But we have yet to take a look at one of the planets itself, and instead have to rely on computer models based on the average properties of the material that surrounds such stars. The limitations of this situation should be obvious. Not only are the models based on a single sample (our solar system), but the average properties of a system may hide important details. For example, the four rocky inner planets in our solar system can just about squeeze into Jupiter's Red Spot, so on average, planets in our solar system are a lot like Jupiter. Most of the planets we've detected elsewhere are pretty similar. Meanwhile, we're really hoping to identify things that look more like earth. 老域名出售

To do that, we're going to eventually have to start looking at the planets themselves. The problems with that are nicely laid out in an article that proposes a workaround. The biggest problems are of scale: at the distances of even nearby stars, the planets are nearly on top of them from our perspective, while the stars themselves would be expected to be 1010 times as bright as any nearby planets. This effectively rules out looking from earth, meaning any solution will have to involve an orbiting telescope. Two telescopes orbiting in concert might do the trick via interference patterns, but we seem to have enough trouble maintaining one such observatory, so that's less than ideal. A single telescope with a precisely shaped insert designed to block out the star's light (called a coronagraph) might do the trick, but the optics would have to be extremely precise, and we wouldn't be able to do any real-world testing on it until it was actually in space.

So, are we basically stuffed? Not entirely, according to the article. The workaround proposed is to make the coronagraph external to the telescope. Although this would also require two orbiting platforms, the second would have to do little more than deploy a 30-50 meter sheet, and then coordinate its position with the telescope. If the positioning can be worked out properly, then fine scale adjustments could be worked out based on actual experience. Even if it fails completely, the expensive part of the observatory—the telescope—should still be able to perform normal observations. Calculations in the article suggest that it could detect everything from the habitable zone of a star outward, and would work at distances of over 30 light years, making a significant number of stars accessible.

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