Scientists directly image brown dwarf for the first time at Keck Observatory

Jan 20, 2014
Direct image detection of a rare brown dwarf companion taken at Keck Observatory. Credit: CREPP ET AL. 2014, APJ

(Phys.org) —A team of researchers led by Justin R. Crepp, the Freimann Assistant Professor of Physics at the University of Notre Dame, has directly imaged a very rare type of brown dwarf that can serve as a benchmark for studying objects with masses that lie between stars and planets. Their paper on the discovery was published recently in Astrophysical Journal.

Initial data came from the TRENDS (TaRgetting bENchmark-objects with Doppler Spectroscopy) high-contrast imaging survey that uses adaptive optics and related technologies to target older, faint objects orbiting nearby stars, and precise measurements were made at the W. M. Keck Observatory on the summit of Mauna Kea, Hawaii. Brown dwarfs emit little light because they do not burn hydrogen and cool rapidly. Crepp said they could provide a link between our understanding of low-mass stars and smaller objects such as planets.

HD 19467 B, a T-dwarf, is a very faint companion to a nearby Sun-like star, more than 100,000 times as dim as its host. Its distance is known precisely, and the discovery also enables researchers to place strong constraints on important factors such as its mass, orbit, age, and chemical composition without reference to the spectrum of light received from its surface.

Precise radial velocity measurements were obtained using the HIRES instrument installed on Keck Observatory's 10-meter, Keck I telescope. The observations, which span 17 years starting from 1996, show a long-term acceleration, indicating that a low-mass companion was "tugging" on the parent star. Follow-up high-contrast imaging observations were then taken in 2012 using the NIRC2 instrument on the Keck II telescope with the adaptive optics system revealing the companion as shown above. Observations were granted through each of the Keck Observatory consortium members, including NASA, the California Institute of Technology, and the University of California.

While scientists understand the light received from stars relatively well, the spectra from planets is complicated and little understood. Understanding , such as HD 19467 B, could be a step towards a fuller understanding of exoplanets.

"This object is old and cold and will ultimately garner much attention as one of the most well-studied and scrutinized brown dwarfs detected to date," Crepp said. "With continued follow-up observations, we can use it as a laboratory to test theoretical atmospheric models. Eventually we want to directly image and acquire the spectrum of Earth-like planets. Then, from the spectrum, we should be able to tell what the planet is made out of, what its mass is, radius, age, etc., basically all relevant physical properties."

HIRES (the High-Resolution Echelle Spectrometer) produces spectra of single objects at very high spectral resolution, yet covering a wide wavelength range. It does this by separating the light into many "stripes" of spectra stacked across a mosaic of three large CCD detectors. HIRES is famous for finding planets orbiting other stars. Astronomers also use HIRES to study distant galaxies and quasars, finding clues to the Big Bang. 


NIRC2 (the Near-Infrared Camera, second generation) works in combination with the Keck II system to obtain very sharp images at near-infrared wavelengths, achieving spatial resolutions comparable to or better than those achieved by the Hubble Space Telescope at optical wavelengths. NIRC2 is probably best known for helping to provide definitive proof of a central massive black hole at the center of our galaxy. Astronomers also use NIRC2 to map surface features of solar system bodies, detect planets orbiting other stars, and study detailed morphology of distant galaxies.

Explore further: Kepler team validates 41 new exoplanets with Keck I

More information: Paper: dx.doi.org/10.1088/0004-637X/781/1/29
Arxiv: arxiv.org/abs/1311.0280

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User comments : 13

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HannesAlfven
1 / 5 (4) Jan 21, 2014
Why is there no mention of the filaments which very obviously appear in the image within the article?
barakn
4.4 / 5 (7) Jan 21, 2014
The "filaments" are leftover light from the heavily-filtered star, which otherwise would have completely saturated the entire image. Filtering was done by shadowing with a 300 mas diameter coronagraph as well as point-spread-function subtraction. In no sense can the linear objects be construed to be anything but light diffracted from the central star by telescope optics.
yyz
5 / 5 (3) Jan 21, 2014
"In no sense can the linear objects be construed to be anything but light diffracted from the central star by telescope optics."

Of course you're right barakn, but Hannes' ignorance of the sophisticated techniques used to compose this image leads him to believe what, that stars are composed of a mass of filamentary Birkeland currents or somesuch?

This EU pareidolia reminds me of similar nonsense, such as this study of "filaments" associated with a gamma ray burst (but are actually instrumental artefacts introduced by the imaging system): https://www.thund...-barrel/

Such is EU "science": It looks like a (Birkeland current, z-pinch), it IS a (Birkeland current, z-pinch).
HannesAlfven
1.7 / 5 (3) Jan 21, 2014
Thank you for the interpretation. Isn't it a bit peculiar that it's not common practice to include this sort of information as common practice? It is in no way actionable knowledge without any understanding of how the imagery was generated.
HannesAlfven
1.8 / 5 (4) Jan 21, 2014
Re: "Such is EU "science": It looks like a (Birkeland current, z-pinch), it IS a (Birkeland current, z-pinch)."

That's not actually the case. In this case, I lack sufficient information to formulate any meaningful critical response.

But, notice that critical thinking is a never-ending process of questioning claims. And it used to be the case that our scientific culture would actually talk about critical thinking, as though it remained a cultural value.

Your own apparent view that websites should not actively support the questioning of the information they are sending at consumers of science is implicit in your suggestion that there is something wrong with interpreting an image from a worldview other than the one being offered. How dare people attempt to use scientific methodology to undermine consensus science …

Come on, people. This isn't the 50's. It's 2014. The fact is that we should be building tools to support such behaviors, rather than ostracizing them.
yyz
5 / 5 (5) Jan 21, 2014
"I lack sufficient information to formulate any meaningful critical response."

Hannes, there's a link to the original paper at the end of the article. Check it out.
barakn
3.7 / 5 (3) Jan 22, 2014
This EU pareidolia reminds me of similar nonsense, such as this study of "filaments" associated with a gamma ray burst (but are actually instrumental artefacts introduced by the imaging system): https://www.thund...-barrel/

Such is EU "science": It looks like a (Birkeland current, z-pinch), it IS a (Birkeland current, z-pinch).

Thanks! That's one of the most egregious examples I've seen. I don't suppose the author of that piece ever bothered to wonder why examples of "dense plasma focus" in Swift x-ray telescope images always contain 12-fold symmetry - no more, no less than 12. If you know the x-ray telescope mirrors are held in place by a 12-armed spider, http://www.swift....all.gif, the real reason is obvious. If the thunderbolts.info people were smart, they would quietly delete that article.
Captain Stumpy
not rated yet Jan 22, 2014
@yyz and barakn
thanks for that!

that link that barakn left has a comma at the end...
DELETE the COMMA for a great pic!

one more nail in the coffin of EU
If the thunderbolts.info people were smart, they would quietly delete that article.

if they were smart, they would not support CRACKPOT science

your suggestion that there is something wrong with interpreting an image from a worldview other than the one being offered

@HA
a view based upon science is invaluable

a view based upon CRACKPOT science needs to be shunned, otherwise the ignorant follow blindly and never comprehend
therefore, it is imperative that CRACKPOT science be pointed out at every turn to insure that the weak minded and lazy dont fall for the stupidity
it is easy for the scientifically challenged to fall for jargon/lingo and a hypothesis that includes a few real bits of science

the well educated/intelligent SHOULD be able to tell the difference...
it falls to those who know to show others
HannesAlfven
1 / 5 (2) Jan 22, 2014
Re: "If you know the x-ray telescope mirrors are held in place by a 12-armed spider, http://www.swift....all.gif, the real reason is obvious."

All you've done here is presented what Daniel Kahneman calls an "associatively coherent" story. Associative coherence is how the subconscious mind evaluates information. The reason why you find this argument appealing is the same exact cognitive process which leads EU enthusiasts to link laboratory plasma physics observations to cosmic morphologies. The subconscious pops stories into your awareness on the basis of the absence or presence of incongruence. Ultimately -- and presumably -- it is the rational mind which makes the final decision of what to believe.

And in the case of the most complex questions man has ever asked, the RATIONAL choice would be to keep our options open. The FEELING that is inducing you to want to winnow your choices in cosmology is ultimately an IRRATIONAL one that originates in your subconscious.
HannesAlfven
1 / 5 (2) Jan 22, 2014
You might contemplate why, if asked, you'd answer that you want more options in cosmology -- and yet, in terms of your actual behavior, it's clear that you are actively trying to reduce your options for belief. Rationally speaking, all new ideas in cosmology would require a reasonable time of investigation before they could parallel the number of arguments and data that the conventional theories exhibit.

Scientists like to pretend that they welcome the discovery of new models in science. That is their rational mind talking. We now see that the subconscious is quite frazzled by the uncertainty of new ideas. Studies reveal that creative ideas are associated by the subconscious with words like "vomit".

You guys are caught here in a drama that is already pre-scripted. You like to imagine that your rational mind is in control of your beliefs. But, you don't even have the tools you need to rationally evaluate a paradigm like the Electric Universe.
HannesAlfven
1 / 5 (2) Jan 22, 2014
To be clear, you have already decided that the EU is false -- regardless of what evidence tomorrow brings. And now, the work that is left is what psychologists call "post-rationalization". It's the exact same thing that a person who is coming out of hypnosis does when he is asked why he was just a few seconds ago barking like a dog. He will literally make a story up to justify his former irrational behavior. It seems so strange to see somebody who has just been hypnotized do this, because it's so obvious, but people on physorg do it every single day, and it's not at all obvious to them: They already have a worldview, and what is left to do now is simply JUSTIFY it, by reversing the flow of decision-making from worldview back to evidence and arguments.

Feel free to pretend like you don't do it. That's actually part of the game.

We don't stand a chance at getting closer to truth in the universe with this nonsense.
Captain Stumpy
5 / 5 (1) Jan 22, 2014
To be clear, you have already decided that the EU is false

@Halfven
nope. I have a pretty open mind
but I asked for empirical data/experimentation/peer reviewed publications/PROOF
and I got links to CRACKPOT websites
I didnt DECIDE, I simply watched REAL SCIENTISTS debunk it
end of story
We don't stand a chance at getting closer to truth in the universe with this nonsense

you are ABSOLUTELY RIGHT
we dont stand a chance getting closer to the TRUTH with EU NONSENSE continually clouding the water
THANK YOU for sharing that

EU is CRACKPOT science
unproven and repeatedly debunked by real scientists
that is NOT to say that there is no real science in the hypothesis
there are SMALL parts that are real

but deciding that the entire thing is real based upon one or two valid pieces is like saying that the tooth fairy is real just because I have real teeth and money in my pocket

barakn
3.7 / 5 (3) Jan 25, 2014
Re: "If you know the x-ray telescope mirrors are held in place by a 12-armed spider, http://www.swift....all.gif, the real reason is obvious."

All you've done here is presented what Daniel Kahneman calls an "associatively coherent" story. Associative coherence is how the subconscious mind evaluates information. The reason why you find this argument appealing is the same exact cognitive process which leads EU enthusiasts to link laboratory plasma physics observations to cosmic morphologies.

No, actually, what I presented was my analysis of the x-ray telescope based on the hundreds of hours I've spent studying optics in general and telescopes in particular, including the math behind it. I think you've performed a form of psychological transference where you accuse people of doing things you yourself are guilty of.