How the brown dwarf blows: Wind speed of a 'failed star' measured for 1st time

rod

Oct 22, 2019
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This was an interesting report on winds at 2MASS J10475385+2124234. I dug a bit into this brown dwarf and found, "Allers et al., 2020 : 2MASS J10475385+2124234 is a T6.5 BD of 0.5 to 10 billion years with an estimated temperature of 880+/-76 K, a rotation period of 1.77 ± 0.04 hours and a magnetic field strength of 5.6 kG. The difference between radio period and infrared period implies a wind of +650 ± 310 m/s proceeding eastward. ", ref -http://exoplanet.eu/catalog/2mass_j10475385+2124234/

It could be 0.5 to 10 billion years old based upon the modeling :) Using 42 Mjup mass and radius, 2 Rjup, a rotation period of 1.77 hours is about 70.496 km/s at its equator and mean density about 2.48 g cm^3. Much larger than Jupiter and spinning much faster too. Only about 34 light-years distance. Seems like a fun place to visit, should get plenty of windy days :)
 
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Mar 19, 2020
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Those are some pretty fast wind speeds. You could really get some power from wind farms at 2MASS J10475385+2124234.

Thinking about the atmosphere of this brown dwarf and Jupiter, I was reminded of studies attempting to find out if any exoplanets have oxygen in their atmospheres, a possible sign of life since it is commonly assumed that O2 is not a stable compound and would need a constant source for replenishment, and life is that very likely source.

It worked for us. And thing out there with an O2 signature, rod?!
 
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rod

Oct 22, 2019
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dfjchem721, *an O2 signature*? Dave, I am not aware of any reports like this. I find it interesting in astronomy how the subject of *habitable* planet has changed over the years. Here is an example from 1911.

“Venus is nearly as large as the earth and, as it is much nearer the sun, its temperature must be higher than that of the earth. The average temperature is estimated to be about 140 degrees F. Various phenomena appear to indicate that the planet is surrounded by a comparatively dense and cloudy atmosphere which, indeed, is apparently seen as a luminous border, in the transits of Venus over the sun’s disk, which occur once or twice in a century. This dense atmosphere strongly reflects the sun’s rays and thus prevents the surface of the planet from attaining a temperature too elevated for highly organized life. The planet would be regarded as habitable.” —Scientific American, March 1911", https://www.scientificamerican.com/article/newsflash-we-could-live-on-venus/
 
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rod

Oct 22, 2019
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FYI, I did find this in my trusty, home database. ""ABSTRACT The combination of high-contrast imaging and high-dispersion spectroscopy, which has successfully been use to detect the atmosphere of a giant planet, is one of the most promising potential probes of the atmosphere of Earth-size worlds. The forthcoming generation of extremely large telescopes (ELTs) may obtain sufficient contrast with this technique to detect O2 in the atmosphere of those worlds that orbit low-mass M dwarfs. This is strong motivation to carry out a census of planets around cool stars for which habitable zones can be resolved by ELTs, i.e. for M dwarfs within ∼5 parsecs. Our HARPS survey has been a major contributor to that sample of nearby planets...", https://www.eso.org/public/archives/releases/sciencepapers/eso1736/eso1736a.pdf
 
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From rod, on old Venus notions: "This dense atmosphere strongly reflects the sun’s rays and thus prevents the surface of the planet from attaining a temperature too elevated for highly organized life. The planet would be regarded as habitable.” —Scientific American, March 1911"

They clearly did not have all the details of Venus! But it could be habitable, if you read enough of the posts by all the dreaming space explorers. They just have to replace its atmosphere, bring in (or dig up) a lot of water for golf courses and suburban sprawl. Otherwise, live a subterranean life. Nobody says you have to live "on" the planet to live on the planet! Imaginations run wild.....

Let us hope the ELTs will find the oxygen. That would be a unique observation, apparently.

Wait, looks like I may have found some O2 after all*:

"The first observed extrasolar planetary atmosphere was made in 2001. Sodium in the atmosphere of the planet HD 209458 b was detected during a set of four transits of the planet across its star. Later observations with the Hubble Space Telescope showed an enormous ellipsoidal envelope of hydrogen, carbon and oxygen around the planet. This envelope reaches temperatures of 10,000 K. The planet is estimated to be losing (1-5)×108 kg of hydrogen per second. This type of atmosphere loss may be common to all planets orbiting Sun-like stars closer than around 0.1 AU. In addition to hydrogen, carbon, and oxygen, HD 209458 b is thought to have water vapor in its atmosphere."

Sounds like a newly formed planet and/or its atmosphere. It won't be losing that quantity for a very long time, one imagines. You must have data on this one (which would be nice confirmation, or not, of this Wiki data at any rate).

But they also note later that :

"The presence of molecular oxygen (O2) may be detectable by ground-based telescopes, and it can be produced by geophysical processes, as well as a byproduct of photosynthesis by life forms, so although encouraging, O2 is not a reliable biosignature. >> In fact, planets with high concentration of O2 in their atmosphere may be uninhabitable.<< "

end quotes

That last observation (my >> <<) would tend to rule out earth at 20% oxygen (surely that qualifies as a "high concentration of O2"). And then they go on about abiogensis (one of my specialties, as you know!). Whoever wrote this might want to stick to the space stuff and forget about life and its formation, activity and longevity. They have a few gaps on that one......

While O2 can clearly be produced by geophysical processes, it is not at all clear that those processes would last for billions of years, like the source of O2 on earth, which is not a geophysical process. Earth is believed to have fossilized photosynthetic algae dating back over 3 bya. No doubt a young planet like HD 209458 b most likely formed O2 by a nonbiological process since it is at high temperature and not exactly what even the wildest imagination would suggest is a habitable planet.

Apparently the opinions of a habitable planet is ever-changing, even as we exchange these messages!

To repeat: "Let us hope the ELTs will find the oxygen."


* https://en.wikipedia.org/wiki/Extraterrestrial_atmosphere
 
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rod

Oct 22, 2019
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FYI. Venus has plenty of O2, in the form of CO2, so does Mars atmosphere. Given the law of abiogenesis (because the law of biogenesis is rejected in evolutionary biology), there should be plenty of vegetation growing on Mars and Venus too. In 1907 and 1943, this was the scientific consensus, especially about Mars. Martians Get Their Water from the Poles, also from 1943, Beings That Are Smarter Than Humans Inhabit the Galaxy Originally published in July 1943

You are correct in stating, "Apparently the opinions of a habitable planet is ever-changing, even as we exchange these messages!"

My observation, the definitions of a habitable planet need to be ever changing in view of the law of abiogenesis at work, everywhere in the universe according to consensus thinking :)--Rod
 
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Rod posted :
"Venus has plenty of O2, in the form of CO2, so does Mars atmosphere. Given the law of abiogenesis (because the law of biogenesis is rejected in evolutionary biology), there should be plenty of vegetation growing on Mars and Venus too. "

Sadly the environmental conditions (temperature mostly) place those planets outside the "Goldilocks Zone". You are playing with me now!

Actually CO2 is not even close to O2. They have very different properties. In terms of aerobic life (animals, some bacteria, etc), C02 is a by-product of metabolism (non-photosynthetic) and O2 drives energy production via electron transport in mitochondria (forming CO2 as waste). In plants, it is CO2 that gets the electron from sunlight to build glucose, and O2 is its "waste" product. One life form's garbage is another life form's gold!

For planetary atmospheres, O2 will typically not last long because it is pretty reactive, unless it is being constantly generated. This is classically shown on earth by "banded iron formations"*, sediments seen as far back as 3.7 bya. They likely result from repeated bouts of O2 generation by photosynthesis, whereby the O2 reacted with free iron ions in the oceans to form ferric oxides. These precipitated out to form the bands. One can see this happen a number of times in the first billions of years of life on earth.*

Eventually, photosynthetic organisms finally gained a "permanent" foothold on the surface, and continued to produce oxygen at a steady rate up until today, or clearly we would not be here. That is why only O2 in exoplanets would likely indicate life, as long as the planet's remaining "air" does not contain nasty compounds that would prevent life like lots of CO2, sulfuric acid, etc. We all know CO2's greenhouse problem re Venus and are trying (not very well) to avoid that. Staying in the Goldilocks Zone is critical to life's survival. The absence of O2 does not eliminate the possibility of life, but may limit how advanced it can become.

We would be looking for an inert atmosphere (non-reducing) with plenty of oxygen, assuming there are places like earth close enough to get the data.

Nothing in your data base on HD 209458 b? Thought it would show that the oxygen as suggested by the link I posted.

 
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rod

Oct 22, 2019
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dfjchem721 (Dave). In 1907-1943, according to consensus science, it was common to see that Venus could be habitable as well as Mars with vegetation. CO2 was in the atmosphere and on earth, CO2 is something that plants love :) That seemed like a logical position concerning the law of abiogenesis for the origin of life on Earth. Who decided to look at exoplanets with O2 only vs. CO2 abundance as evidence of life or supporting life? If the law of abiogenesis is indeed at work in the universe, I would think plants would evolve on exoplanets, rich with CO2 atmospheres as well. Mars has always been considered to be habitable, just like meteorite reports of ALH84001 during the Clinton Administration and 1907 reports of vegetation on Mars or 1943. This goes to the heart of the methodology used to determine a habitable exoplanet with life on it and defining. O2 is today's gold, what about plants using CO2?
 
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Firstly, there is no "law of abiogenesis", but there probably should be. Just like there should be a "law of biological evolution".

There is general consensus among biochemists that original life forms arose in a reducing atmosphere that did not contain O2. Energy was derived from chemicals within the seas (likely from thermal vents), since photosynthesis would require a highly evolved life form. Trapping photons and converting them into chemical energy is not considered an early-stage evolutionary development, but rather a much later-stage. The complexity of such a process is rather profound.

It is believed that RNA, not DNA, was the first biopolymer to generate life, and it is unstable in a high O2 environment (compared to DNA). That is why I mentioned that lack of O2 does not rule out life, but probably limits its complexity.

Since photosynthesis is driven by a complex protein assembly known as the "photosynthetic reaction center", its evolution would have had to wait for the evolution of proteins into the biochemical mechanisms of life as we see it today. Such a process probably took 100s of millions of years.

I am going to take a wild guess and suggest that "consensus science" from 1907-1943 has undergone some serious changes in places. Biochemistry would be near the top of the list! The structure of DNA was determined in 1953, and from it the first biopolymers of life (polynucleotides) started to be revealed, and the abiogensis of life could then be postulated on a more sound basis. The kick-start to the first living organism remains a complete mystery.
 
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rod

Oct 22, 2019
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Okay Dave :) The *law of abiogenesis* and *law of biological evolution* are not the same as Kepler's planetary laws, Newton's laws of motion, or gravity. Astronomy has documented these laws operate in other areas of the solar system and universe too, e.g. binary stars, exoplanets, the orbits of the Galilean moons. The *law of abiogenesis* and *law of biological evolution* is not documented in other places. *The kick-start to the first living organism remains a complete mystery*. Good objective science answer :)--Rod
 
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Okay, thanks rod!

Back to that dwarf star HD 209458 b that people claimed to see some oxygen in its atmosphere , along with hydrogen, carbon, and water maybe. Don't recall now.

Does your data base confirm that HD 209458 b reveals the presence of O2 in its atmosphere? And I am going to guess that the carbon is coming from CO2, assuming this dwarf star even exists. Who knows what all gets put into Wiki is accurate. I am betting your data base is more precise.
 
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rod

Oct 22, 2019
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Dave, my home database shows earlier reports on HD 209458 b as losing atmosphere. Newer reports do indicate H2O observed. Water vapor detection in the transmission spectra of HD 209458 b with the CARMENES NIR channel Here is another on the atmosphere from 2020, Modelling the He I triplet absorption at 10 830 Å in the atmosphere of HD 209458 b I note this in the April 2020, NASA ADS report. "Based on the energy-limited escape approach and assuming heating efficiencies of 0.1-0.2, we find a mass-loss rate in the range of (0.42-1.00) ×1011 g s-1 and a corresponding temperature range of 7125-8125 K. Conclusions: The analysis of the measured He I triplet absorption spectrum significantly constrains the thermospheric structure of HD 209458 b and advances our knowledge of its escaping atmosphere."

The temperature of 7125 - 8125 K is hot. A good temperature on Earth is 288 K or 15C :)--Rod
 

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