Scientists Can Pinpoint Surface Gravity On Other Stars (bbc.com)

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."

Comments

Yeah, sure

[Anonymous Coward]

Please pinpoint the "surface" of a star, first.

Re:Yeah, sure

[Anonymous Coward]

The surface of a star is where the fusion reactors sit.

Re: Yeah, sure

[Anonymous Coward]

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.

Re: Yeah, sure

[mikael]

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.

Re: Yeah, sure

[Deadstick]

It's an insightful post marred by an obvious spellcheck error, not a grammar error. Cut the guy some slack.

Re: Yeah, sure

[wbr1]

Read it as effective, not effect I've. God, some people are as dense as stellar material.

Re: Yeah, sure

[RockDoctor]

Don't let this degenerate matter degenerate into something that matters.

Re:More BBC Spam

[Anonymous Coward]

You piss off. How is it spam?

Better source

[ihtoit]

https://astronomynow.com/2016/... If you're going to post breaking stuff like this, at least use a fucking reputable source!

Re:Better source

[wonkey_monkey]

What's so disreputable about the BBC, particularly when it comes to science reporting?

Re:Better source

[mikael]

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 cod and crustaceans, krill, squid, octopus, cod. mussels & crustaceans

Bearded seals: The bearded seal diet consists primarily of crustaceans (shrimps and crabs), mollusks (clams, snails and whelks), and some fish such as sculpin, flatfish, and cod.

Ringed and Bearded seals live on the ice flows and make ice holes for themselves.
"They prefer to rest on ice floe and will move farther north for denser ice. Two subspecies can be found in freshwater."

Crustaceans: Eat absolutely everything as scavengers
Arctic cod: Eat Copepods and marine worms

Flatfish: polychaetes and gammarids (many others)
http://journal.nafo.int/J30/li...

Sculpin: aquatic insect larvae, but will also eat crustaceans, small fish, fish eggs, and some plant material.

http://www.scientificamerican....

http://animals.mom.me/decline-...

Re:Better source

[wonkey_monkey]

According to the BBC, the polar bears will drown due to global warming.

Where's your link for that claim?

Re:Better source

[mikael]

https://www.youtube.com/watch?...

http://www.dailymail.co.uk/sci...

Re:Better source

[wonkey_monkey]

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.

Re:Better source

[ClickOnThis]

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.

Re:Better source

[Anonymous Coward]

>Savile

In its nearly 100 years of existence I dare say it has employed a number of disreputable characters, some of whom have been found guilty of heinous crimes. Savile was not found guilty in a court of law of any crime. However, despite that but in view of the the many disturbing allegations the BBC have apologised for their actions unreservedly.

>WTC7.

fair enough, no argument with that obviously as David Attenborough and Mr Bean have both admitted responsibility for planting the magic fairy dust.

>Top Gear.

Sure, it's a really shit program that was compered and watched by idiots, but as the national broadcaster it's only fair that they provide jobs and programs for British idiots.

> Election coverage.

they provide election coverage, but again that is part of their remit, so can't be held against them. IF you mean the quality of their Election programming or some bias you believe they have, how about giving us some details?

> Question Time (every question is prescreened and seriously canned, some might even say scripted, and the audience is cherry picked)

My understanding of the process from publicly available info and someone who has been on it; All participants are interviewed beforehand and they are asked to write out their questions. Dimbleby chooses the main questions beforehand, but subsidiary ones on the fly. The programme shown the same day it is recorded and of course can be edited but people who attend can always point this out and no restrictions of personal recording is made. It isn't a "free for all" and with any programme a certain amount of control is necessary and I doubt that anyone really thinks otherwise. It's a decent attempt at a public debate on prime time TV.

>that statue of the priest and the little boy above the London Broadcasting House entrance.

I guess you mean Prospero and Ariel - from a Shakespere play. The sculptor laterly admitted to abusing children and dogs and some people feel that it is insensitive that it is displayed. Others disagree.

>The BBC really are shameless liars, paedophile apologists and propaganda merchants.

Nope. You are entitled to your opinion and in some cases over the years they may have been guilty of the former and later. But nothing you have written has given any real proof of their guilt. I am sure that when we have been at war they have been guilty of some level of of obfuscation and propaganda. I can't think of any news outlet that isn't.

With all its faults I believe it strives to be independent of significant political or commercial bias or influence. Other than my opinion the only evidence of that is that acquaintances of mine of all political shades tend to think it is biased against them.

For decades it has been trusted and listened to by people all over the world who appreciate its impartiality.

Re:Better source

[RockDoctor]

Which part of "science reporting" did you misunderstand?

Re:More BBC Spam

[thinkwaitfast]

But didn't you read the part about

and maybe life

?

affect on dark matter calculations?

[Anonymous Coward]

Be interesting to see how if affects calculations for dark matter mass

No they cant

[Anonymous Coward]

Liar

Yes they can

[Anonymous Coward]

Twat

when gf gets close,

[Anonymous Coward]

my gravity detector goes on alert, defying gravity.

Link to the full research paper

[StupendousMan]

... is here:

http://advances.sciencemag.org...

The authors have not placed a copy on the arXiv preprint server ... strange.

Re:Link to the full research paper

[Anonymous Coward]

If you observe the server a longer period of time, an appearance of the paper will appear.

Re:Link to the full research paper

[Anonymous Coward]

This paper was published in the journal Science. Science and Nature are the two journals with enough clout to demand that researchers don't make the same article available on the arXiv preprint server. The researchers would probably prefer to also post the article to the arXiv, but being able to say that they've published a paper in Science carries a lot of prestige, so they tolerate the restriction in this case.

If this follows the pattern I've seen a few times, then there'll be a related, longer paper published in a few months, containing all the meaty technical details, in a lower-impact journal - and that one will also be posted to the arXiv.

No they cant

[Anonymous Coward]

And such theories should not be called scientific.

Huh?

[Anonymous Coward]

What's the difference between asteroseismology and astroseismology?

Re: Huh?

[Anonymous Coward]

One is the combination of all Greek-based words (asteroseismology) and one is a mixture of Greek and Latin root words (astroseismology). The term used in the scientific literature is asteroseismology.

Re:Huh?

[RockDoctor]

A mis-trained or un-trained spelling checker.