5400mph winds discovered hurtling around exoplanet

_Tombstone_

http://phys.org/news/2015-11-5400mph-hurtling-exoplanet.html

Winds of over 2km per second have been discovered flowing around planet outside of the Earth's solar system, new research has found.

The University of Warwick discovery is the first time that a weather system on a planet outside of Earth's solar system has been directly measured and mapped.

The wind speed recorded is 20x greater than the fastest ever known on earth, where it would be seven times the speed of sound.

Commenting on the discovery lead researcher Tom Louden, of the University of Warwick's Astrophysics group, said:
"This is the first ever weather map from outside of our solar system. Whilst we have previously known of wind on exoplanets, we have never before been able to directly measure and map a weather system."

Discovered on the exoplanet HD 189733b, the Warwick researchers measured the velocities on the two sides of HD 189733b and found a strong wind moving at over 5400mph blowing from its dayside to its night side. Mr Louden explains:
"HD 189733b's velocity was measured using high resolution spectroscopy of the Sodium absorption featured in its atmosphere. As parts of HD 189733b's atmosphere move towards or away from the Earth the Doppler effect changes the wavelength of this feature, which allows the velocity to be measured".

That's mad. We can even reliably predict our own weather for tomorrow!

ps200306

I remember reading about wind speeds within our own solar system. Did you know that they increase as you travel outward from the sun? This seems counterintuitive because it's the sun that powers the weather. You would think less heat means less powerful winds. But apparently less heat also means less turbulence, and this is the decisive factor that lets the winds blow increasingly fast in the outermost gas giants.

littlemac1980

I remain very very skeptical about all these so called "observations" of exo-planets and their characteristics/properties.

There are more and more astounding "discoveries" being announced that are based very much assumed science in my opinion.

Unless I'm mistaken, we are really just fitting our current understanding of space to observed anomalies in our measurements of certain areas or light sources and it's really a very large leap imo to be declaring as fact that these planets if they do exist, exist in the form we are speculating they do. Now they appear to be observing some sort of doppler shift and saying the only thing that could account for such an observation is an atmospheric wind of 5000+km per hour.

Is it possible at all that the observed discrepancy is the result of an altogether different cause not based upon the speculation that there is an exo-planet there, or based on the assumption that a speculated planet would have a speculated mass and a speculated mean distance from the star, with a speculated atmosphere.

It just seems like an enormous waste of scientific resources to me, with every "scientist" engaged in this silly treasure hunt trying to out-do the last one to fit some more bizarre possibility to a slight divergence in 1's and 0's that are being observed from a particular expected measurement, and at an enormous distance too.

It won't happen in my lifetime, but I'm going with my gut here and my understanding of human nature and I'm going to call this out as a big scientific blunder and waste of time in general - imo there's some merit to type of science being carried out here - but seriously, you'd think they were landing probes on these "planets" with the way they are described in scientific reports.

When we recently found enormous mountains on Pluto and what looks like tectonic/geological activity it was something that would (as far as I know) never have been speculated. That's a planet in our solar system.

When we recently found what appears to be ice on Mercury it was something that would (as far as I know) never have been speculated.

These exo-planet discoveries (all of them) are to the best of my knowledge based on a huge amount of speculation, and based on very thin evidence.

Saying there is likely to be something which could be a planet orbiting a certain star based on periodic dips in magnitude of the star is not tantemount to saying there is definitely a planet there.

Of course I'm no expert on all this - I just wish to convey my opinion.

If there is something more concrete someone can point me to - Some solid proof that could provide a solid basis for the further assumptions being made I really would love to read up on it. I love the science of the stars, I love science fiction too.

ps200306

littlemac1980 wrote: »

I remain very very skeptical about all these so called "observations" of exo-planets and their characteristics/properties.

There are more and more astounding "discoveries" being announced that are based very much assumed science in my opinion.

Unless I'm mistaken, we are really just fitting our current understanding of space to observed anomalies in our measurements of certain areas or light sources and it's really a very large leap imo to be declaring as fact that these planets if they do exist, exist in the form we are speculating they do.

littlemac1980, I agree it's very hard for "science-interested" non-professionals like you (presumably) and me (definitely) to separate real science from hype in these sorts of announcements. Depending on how "tabloid" the report is, we may get anything from sober analysis to near hysteria (as with the "alien megastructures" the other week). I don't think such sensationalism does anyone any favours -- in some it will engender the sort of cynicism you're voicing, while the less discerning may believe we either have made, or are imminently about to make, contact with real live aliens.

I suppose the popular science reporters have to sell copy, so there is an incentive to be as sensational as possible. The scientists -- while they would never commit such wild claims to print themselves -- are probably not too unhappy either that their work gains a higher profile, which is good for their careers and their research grants.

Scientists themselves come in different shapes and sizes. That "alien megastructures" story originated with a paper by Boyajian et al. who never once mentioned aliens, but was then taken up by Wright and Siemion -- the latter being director of the SETI Researcher Centre at UC Berkley. With Berkley vying for it's slice of the new $100m funding pie announced this summer, it doesn't take a rocket scientist to figure out that stories about alien megastructures filling news headlines is extremely good news for careerist academics and their institutions, no matter how tenuous the science.

However, not all research is like that. In any particular case -- such as those exoplanetary winds -- I guess you have to dig deeper to figure out how mature the underlying science is, and how tenable the claims. This is very difficult indeed for the non-professional. For starters, it probably means going behind the headlines and the glossy articles to the actual research. These stories are always based on a particular published piece of work. Usually you can Google the primary resource, either directly or on Google Scholar, and you will be able to find at least the abstract of the published paper on some academic database or other.

In this particular case, the academic article is referenced directly from bottom of the one that Tombstone linked. The preprints on arXiv.org are a godsend, with physics and astronomy especially well represented among their million-plus papers. Previously you'd need some sort of academic subscription to access such papers. Even without formal qualifications, the interested layperson should be able to glean a fair amount of information from them.

From general reading I have some idea of the historical background. Spectroscopy is about 200 years old, astronomical spectroscopy about 150 years old, the idea of using spectroscopy to measure rotational parameters of extra-solar bodies is about 120 years old. The Rossiter-McLaughlin effect was eighty years old last year.

In short, spectroscopy has been around a long time and can be an extremely exact technique. I would hazard an opinion that we know way more about the universe from spectrographic analysis than from plain old astronomical images. All the early exoplanet detections were based on spectrographic measurements of parent star radial velocities. On the other hand, those plain old images (combined with precise photometry) are the best way of doing bulk detection of exoplanets by the transit method, in programs like Kepler.

So coming back to your first point about whether exoplanets are real or a convenient explanation for "observed anomalies in our measurements of certain areas or light sources" ... I think you are too pessimistic on this one. They didn't launch a telescope into space on a hunch that it might see some anomalies. By the time Kepler was launched -- amazingly, less than a decade after the first photometric transit detection -- they had already precisely modelled what sort of planets it would be capable of detecting, what proportion of stellar systems would be oriented just right to show visible transits, what mix of exposure times would be most effective, how many repeat observations would be necessary to catch transits of planets at different orbital radii, and what the overall detection rates and distribution of planet sizes would likely be.

Roll forward five years, and the program has been wildly successful. Lest we think that it was just confirming biases, there have been many surprises, such as the preponderance of planets between the size of Earth and Neptune, which are not represented at all in our own solar system. On the other hand, the transit method allows us to calculate planetary radii which, coupled with follow-up radial velocity measurements to get the planet's mass, gives us density measurements which are in plausible ranges.

The basic technique of "phase-folding" multiple observations to produce composite high-resolution light curves relies on the sort of regularity that only a planetary orbit could plausibly provide. As well as our own sun, we've managed to look at the surfaces of nearby stars, and they simply don't have the sort of long-lived surface features that might mimic a planetary transit. Not only that, but Kepler has detected stars with multiple transiting planets for which we would require precisely synchronised differential surface rotation rates if we were to explain them as stellar features. (Not to mention the fact that these planets perturb each other according to expected gravitational resonances). I don't think there could really be any serious doubt expressed about the fact that the Kepler detections really are exoplanetary systems.

littlemac1980 wrote: »

Now they appear to be observing some sort of doppler shift and saying the only thing that could account for such an observation is an atmospheric wind of 5000+km per hour.

Is it possible at all that the observed discrepancy is the result of an altogether different cause not based upon the speculation that there is an exo-planet there, or based on the assumption that a speculated planet would have a speculated mass and a speculated mean distance from the star, with a speculated atmosphere.

It just seems like an enormous waste of scientific resources to me, with every "scientist" engaged in this silly treasure hunt trying to out-do the last one to fit some more bizarre possibility to a slight divergence in 1's and 0's that are being observed from a particular expected measurement, and at an enormous distance too.

I think what may not be obvious from the reporting, or even from the published paper, is that HD 189733 b is one of the most extensively studied exoplanets. It's not a random find among the Kepler data, in fact it was one of the earlier ground-based discoveries. That's not surprising, as Wikipedia says: "Being the closest transiting hot Jupiter to Earth, HD 189733 b is a subject for extensive atmospheric examination. HD 189733 b was the first extrasolar planet for which a thermal map was constructed, to be detected through polarimetry, to have its overall colour determined (deep blue), to have a transit detected in x-ray spectrum and to have carbon dioxide detected in its atmosphere."

Recapping some of the basic parameters that transit and follow-up radial velocity measurements give us: we've got the radius (from photometry measurements), the mass (from radial velocity measurement, the density (which is the quotient of mass and volume), the orbital period (from transit observations), the orbital radius (from the period and Kepler's laws). Those can't really be disputed. That characterises the planet as being a gas giant larger than Jupiter, but orbiting its parent star ten times closer than Mercury is to our Sun. The tidal forces on the planet can easily be calculated, and basic physics dictates that it would very quickly end up in tidal lock. That means it has one face in permanent darkness, and the other getting roasted by its star. We know the dark side's thermal spectrum which tells us how much heat is being transferred from one side to the other. Computer models predict a powerful jet transporting that heat, so even in advance of the measurements a very high speed wind is not only plausible but expected.

You can read the paper yourself. It does take quite a bit of wading through, and you might have to look up a lot of terms. It goes into a whole host of reasons why the measurement of the sodium doublet lines can be reliably taken to properly represent the intrinsic movement of the atmosphere. All sorts of alternate explanations are considered and ruled out. Bear in mind that the same sodium doublet lines have been measured for years on HD 189733 b now. This is just the latest attempt at improved precision. The measurements are all provided, with appropriate error bars and estimates of uncertainty. The actual paper is nothing like the superficial "hey look, we found a planet with 5,000 kph winds" tone of the glossy reports. This is really good and exacting science.

littlemac1980 wrote: »

It won't happen in my lifetime, but I'm going with my gut here and my understanding of human nature and I'm going to call this out as a big scientific blunder and waste of time in general - imo there's some merit to type of science being carried out here - but seriously, you'd think they were landing probes on these "planets" with the way they are described in scientific reports.

When we recently found enormous mountains on Pluto and what looks like tectonic/geological activity it was something that would (as far as I know) never have been speculated. That's a planet in our solar system.

When we recently found what appears to be ice on Mercury it was something that would (as far as I know) never have been speculated.

These exo-planet discoveries (all of them) are to the best of my knowledge based on a huge amount of speculation, and based on very thin evidence.

Saying there is likely to be something which could be a planet orbiting a certain star based on periodic dips in magnitude of the star is not tantemount to saying there is definitely a planet there.

Of course I'm no expert on all this - I just wish to convey my opinion.

If there is something more concrete someone can point me to - Some solid proof that could provide a solid basis for the further assumptions being made I really would love to read up on it. I love the science of the stars, I love science fiction too.

I completely understand the skepticism. Studying the techniques used in exoplanet detection completely blew my mind. (I was lucky to have time on my hands and a lifelong casual interest in the topics, so I went and did a degree in astronomy and planetary science just for fun). I'd be more than happy to point you at some textbooks if you'd like to delve further. The main exoplanet one I used is here, you can look inside from the preview link here. Note that books go out of date very quickly in this area, and that one was published just as Kepler was launched, and way before it produced any data. It does have material specifically about HD 189733 b though (unfortunately not available in the online preview).

littlemac1980

Thanks for the reply ps200306.

I really appreciate your comments, in particular the great deal of relevant content and information.

I will indeed check the paper you mentioned and also the book and other sources you refer to.

It's great to get put back in my box in such a well meaning and informative way.

ps200306

:pac: Hey no worries! We're all just learning.