Hubble: Clear Skies on Exo-Neptune

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Hubble: Clear Skies on Exo-Neptune

Post by bystander » Wed Sep 24, 2014 7:16 pm

Clear Skies on Exo-Neptune
ESA Hubble Science Release | 2014 Sep 24
Astronomers using data from the NASA/ESA Hubble Space Telescope, the Spitzer Space Telescope, and the Kepler Space Telescope have discovered clear skies and steamy water vapour on a planet outside our Solar System. The planet, known as HAT-P-11b, is about the size of Neptune, making it the smallest exoplanet ever on which water vapour has been detected. The results will appear in the online version of the journal Nature on 24 September 2014.

The discovery is a milestone on the road to eventually finding molecules in the atmospheres of smaller, rocky planets more akin to Earth. Clouds in the atmospheres of planets can block the view of what lies beneath them. The molecular makeup of these lower regions can reveal important information about the composition and history of a planet. Finding clear skies on a Neptune-size planet is a good sign that some smaller planets might also have similarly good visibility. ...
NASA Telescopes Find Clear Skies and Water Vapor on Exoplanet
NASA | STScI | JPL-Caltech | 2014 Sep 24

Major Milestone in the Search for Water on Distant Planets
College of Computer, Mathematical, and Natural Sciences
University of Maryland | 2014 Sep 24

Water vapour absorption in the clear atmosphere of a Neptune-sized exoplanet - Jonathan Fraine et al
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Caltech: Getting To Know Super-Earths

Post by bystander » Fri Oct 17, 2014 7:51 pm

Getting To Know Super-Earths
California Institute of Technology | 2014 Oct 15
"If you have a coin and flip it just once, what does that tell you about the odds of heads versus tails?" asks Heather Knutson, assistant professor of planetary science at Caltech. "It tells you almost nothing. It's the same with planetary systems," she says.

For as long as astronomers have been looking to the skies, we have had just one planetary system—our own—to study in depth. That means we have only gotten to know a handful of possible outcomes of the planet formation process, and we cannot say much about whether the features observed in our solar system are common or rare when compared to planetary systems orbiting other stars.

That is beginning to change. NASA's Kepler spacecraft, which launched on a planet-hunting mission in 2009, searched one small patch of the sky and identified more than 4,000 candidate exoplanets—worlds orbiting stars other than our own sun. It was the first survey to provide a definitive look at the relative frequency of planets as a function of size. That is, to ask, 'How common are gas giant planets, like Jupiter, compared to planets that look a lot more like Earth?'

Kepler's results suggest that small planets are much more common than big ones. Interestingly, the most common planets are those that are just a bit larger than Earth but smaller than Neptune—the so-called super-Earths. ...

Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b - Heather A. Knutson et al
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Re: Caltech: Getting To Know Super-Earths

Post by BDanielMayfield » Mon Oct 20, 2014 11:43 pm

California Institute of Technology | 2014 Oct 15

Kepler's results suggest that small planets are much more common than big ones. Interestingly, the most common planets are those that are just a bit larger than Earth but smaller than Neptune—the so-called super-Earths. ...


As small things usually out-number large things small planets being "much more common than big ones" isn't supprizing, but that "the most common are ... the so-called super-Earths" is, I think. In my opinion this isn't a real finding of a fact of nature, but merely a selection bias due to how hard it is to detect small planets. But just because we can't find them yet we shouldn't assume that small planets don't exist in large numbers.

Bruce
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Re: Caltech: Getting To Know Super-Earths

Post by Ann » Tue Oct 21, 2014 2:49 am

BDanielMayfield wrote:
California Institute of Technology | 2014 Oct 15

Kepler's results suggest that small planets are much more common than big ones. Interestingly, the most common planets are those that are just a bit larger than Earth but smaller than Neptune—the so-called super-Earths. ...


As small things usually out-number large things small planets being "much more common than big ones" isn't supprizing, but that "the most common are ... the so-called super-Earths" is, I think. In my opinion this isn't a real finding of a fact of nature, but merely a selection bias due to how hard it is to detect small planets. But just because we can't find them yet we shouldn't assume that small planets don't exist in large numbers.

Bruce
Absolutely, Bruce.

We see in our own solar system that the small bodies vastly outnumber the large ones. There is one Jupiter, one Saturn, two Neptunes, two Earths, one Mars, several Mercuries - Mercury, Luna, Titan, Ganymede, Callisto, Triton, maybe Io - and huge numbers of smaller moons and other bodies. The way I see it, there is no reason whatsoever to think that other solar systems don't follow the same trend.

But how common is the Earth? When people talk about other Earths, I think most of them think about other planets with abundant life on them.

I don't think our own solar system gives us a clue as to how common "Earths" are. So far, we have one example of a planet with abundant life, and that is not enough to build any statistics on.

Ann
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