Scientists Can Pinpoint Surface Gravity On Other Stars (bbc.com) 38
An anonymous reader writes: Astronomers have developed a new technique to measure the surface gravity on distant stars. Earlier techniques relied on measuring the amount of light coming from the star, and were unreliable beyond a certain distance. The new work instead focuses on variations in the light over a longer period of time — indications of turbulence and vibration — which can provide detailed information at greater distances. One of the researchers, Professor Jaymie Matthews, said, "Our technique can tell you how big and bright is the star, and if a planet around it is the right size and temperature to have water oceans, and maybe life." According to their research paper, "We have tested this for a well-defined subsample of the Kepler catalog and found it to maintain a high accuracy, about six times better than that of the flicker method. In addition, it is more noise-tolerant than asteroseismology and gives a reasonably accurate surface gravity g for stars that are too faint for a reliable asteroseismic analysis. Therefore, the time scale technique makes it possible to study otherwise poorly understood stars, which will lead to better characterization of exoplanetary systems both individually and statistically."
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and maybe life
?
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The surface of a star is where the fusion reactors sit.
Re: Yeah, sure (Score:3, Informative)
The density of the sun changes eleven orders of magnitude in the 2000 km above the photosphere. In a proportionate 20 km of Earth, from just below the surface to 20 km above, there is only a five orders of magnitude change in density. The chromasphere is a rather drastic boundary that works quite well as reference point to call the effect I've surface.
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Photosphere is the layer of the Sun that has the granulation pattern of plasma and the solar flares. The Chromosphere is the area that gives the Sun a reddish halo, and the Corona is the layer only visible during an eclipse.
The photosphere/chromosphere is a boundary layer with a density change greater than that of the Earth's ocean/atmosphere boundary layer.
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It's an insightful post marred by an obvious spellcheck error, not a grammar error. Cut the guy some slack.
Better source (Score:1)
https://astronomynow.com/2016/... [astronomynow.com] If you're going to post breaking stuff like this, at least use a fucking reputable source!
Re:Better source (Score:4, Insightful)
What's so disreputable about the BBC, particularly when it comes to science reporting?
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According to the BBC, the polar bears will drown due to global warming. This is because the seals are spending more time in the deep ocean catching fish, forcing the polar bears to swim more often to catch them.
Let's follow the food chain ..
"Diet. Polar bears feed almost exclusively on ringed seals and bearded seals. They are also known to eat walrus, beluga whale and bowhead whale carcasses, birds' eggs, and (rarely) vegetation. Polar bears travel great distances in search of prey."
Ringed seals eat: Arctic
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According to the BBC, the polar bears will drown due to global warming.
Where's your link for that claim?
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https://www.youtube.com/watch?... [youtube.com]
http://www.dailymail.co.uk/sci... [dailymail.co.uk]
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First link: could you give me a timestamp so I don't have to watch the whole 30 minutes?
Second link: no mention of the BBC.
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I watched the first BBC link, and didn't recall hearing anything about polar bears drowning.
Not that I doubt the veracity of the claim that polar bears are threatened by climate change.
Link to the full research paper (Score:5, Informative)
http://advances.sciencemag.org... [sciencemag.org]
The authors have not placed a copy on the arXiv preprint server ... strange.
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