Explanation: Laser guide stars and adaptive optics sharpened this stunning ground-based image of stellar jets from the Gemini South Observatory, Chilean Andes, planet Earth. These twin outflows of MHO 2147 are from a young star in formation. It lies toward the central Milky Way and the boundary of the constellations Sagittarius and Ophiuchus at an estimated distance of some 10,000 light-years. At center, the star itself is obscured by a dense region of cold dust. But the infrared image still traces the sinuous jets across a frame that would span about 5 light-years at the system's estimated distance. Driven outward by the young rotating star, the apparent wandering direction of the jets is likely due to precession. Part of a multiple star system, the young star's rotational axis would slowly precess or wobble like a top under the gravitation influence of its nearby companions.
The explanation says that possibly several stars form the cluster, suppose that the star in question is located in opposition to a group of massive stars and when the stellar axis approaches the gravitational influence of these massive stars they possibly accelerate their precession forming the jets of powder as we see it in the image, one more crooked than the other. (Always to the best of my understanding and knowledge)
I hope some more of you pros will add to the information. What are the colors in the jets indicating? Why are the stars "fuzz balls" instead pf producing spikes? Links indicate this may be at least a triple star system. This is a fascinating photo that generates a lot of questions.
As to why the baby star is emitting jets, I guess it must be because it is still accreting matter and has an accretion disk. It would be emitting jets for the same reason that some black holes are emitting jets, because they have an accretion disk that is accreting matter.
So what do the colors of the APOD mean? Don't ask me. I have no idea. All I'm sure of is that the colors are not "true" or optical ones, and therefore they don't mean anything to me.
Ann wrote: ↑Fri Jan 21, 2022 6:47 pm
It would be emitting jets for the same reason that some black holes are emitting jets, because there is an accretion disk accreting matter.
A pair of jets is a sign predicting the end of the accretion disk, because the accretion is running away.
But M87* still got a pair jets, however thin, after billions of years after it had blown away the gas disk and made M87 an elliptic galaxy.
That's how they do things there: no disk for the galaxy, but still feeding the accretion disk for the central supermassive black hole.
I wonder if the dark stripe lining the bottom visual edge of the jet to the left belongs of the lobe.
If, in fact, the dust eclipsing the new-born star in our line of sight belongs to one lobe.
Then the lobes must be shaped like a propeller
Even more doubtful, but can the black (the absence of the stars of Milky Way's core at 20-30 kly) at the bottom right of the posted image belong the right lobe?
Young Star Jet MHO 2147..jpg
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Last edited by VictorBorun on Fri Jan 21, 2022 9:15 pm, edited 2 times in total.
Ann wrote: ↑Fri Jan 21, 2022 6:47 pm
So what do the colors of the APOD mean? Don't ask me. I have no idea.
All I'm sure of is that the colors are not "true" or optical ones...
https://www.gemini.edu/instrumentation/gsaoi wrote:
<<The Gemini South Adaptive Optics Imager (GSAOI) is a near-infrared adaptive optics camera used with the Gemini Multi-conjugate Adaptive Optics System (GeMS) on Gemini South. It provides near-diffraction limited images in the 0.9 - 2.4 μm wavelength range. In the adaptive optic sense, GSAOI is a wide-field imaging system with a 4080 x 4080 pixel detector format.>>
Band . . . Wave-length
------------------------------- H2(1-0). . 2.122 μm K. . . . . . 1.635 μm
https://en.wikipedia.org/wiki/Siemens_(unit) wrote:
<<The siemens (symbol: S) is the derived unit of electric conductance, electric susceptance, and electric admittance. Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively; hence one siemens is redundantly equal to the reciprocal of one ohm (Ω−1). The 14th General Conference on Weights and Measures approved the addition of the siemens as a derived unit in 1971. The unit is named after Ernst Werner von Siemens.
Another name for the siemens is the mho. As the reciprocal of one ohm, it is the word ohm spelled backwards, at the suggestion of Sir William Thomson (Lord Kelvin) in 1883. NIST's Guide for the Use of the International System of Units (SI) refers to the mho as an "unaccepted special name for an SI unit", and indicates that it should be strictly avoided. The inverted capital omega symbol (℧), while not an official SI abbreviation, is less likely to be confused with a variable than the letter 'S' when writing the symbol by hand. The usual typographical distinctions (such as italic for variables and roman for units) are difficult to maintain. Likewise, it is difficult to distinguish the symbol 'S' (siemens) from the lower-case 's' (seconds), potentially causing confusion.>>
Lots of strange posts today that I have failed to understand, but I'll second the question about the "fuzzball" appearance of the stars. They all look like little globular clusters! And there is not a diffraction spike to be found. I guess it must be due to the adaptive optics system?
-- "To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}
Chris Peterson wrote: ↑Fri Jan 21, 2022 10:52 pm
If the goal is clarity, it's entirely possible to map the colors in an arbitrary fashion.
We may have some intuition as for shorter wavelengths to be scattered by gas and dust at wider angles
DarkNebulaVd_HmoRuuth_4096 - Beta Chameleon.jpg
We're seeing different processes in these wavelengths. If anything, our intuition is likely to fail us. I prefer to depend upon informed reason, meaning that I know the wavelengths and I know the color assignments.
Chris
*****************************************
Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
Ann wrote: ↑Fri Jan 21, 2022 6:47 pm
So what do the colors of the APOD mean? Don't ask me. I have no idea.
All I'm sure of is that the colors are not "true" or optical ones, and therefore they don't mean anything to me.
Hey, I always prefer the shorter wavelengths to to be mapped to bluer hues than the longer wavelengths! I just meant that I had no idea what wavelengths were involved here.
Ann wrote: ↑Sat Jan 22, 2022 4:57 pm
Hey, I always prefer the shorter wavelengths to to be mapped to bluer hues than the longer wavelengths!
There is one more thing: the colours* of stars.
Even the two colour-filters image here shows which stars are colder: the amberish ones.
The few foreground stars here show that the colder stars are usually dimmer, but only if the mapping IR wavelengths to RGB subpixels is monotonic.
Now the background stars that I guess are in Milky Way's core 20-30 kly away show no such correlation. I wonder why.
_______
* my browser's spellchecker is against "colors" without British "u". It tolerates wavelengths though.
Ann wrote: ↑Sat Jan 22, 2022 4:57 pm
Hey, I always prefer the shorter wavelengths to to be mapped to bluer hues than the longer wavelengths!
The APOD would have been less aesthetically pleasing with the colors reversed, IMO.
Yeah, right. Because people like to think that red is a "hotter" color than blue, so it "makes sense" that the central, hotter part of the jet is red, while the outer, cooler part is blue... right?
Ann wrote: ↑Sat Jan 22, 2022 4:57 pm
I just meant that I had no idea what wavelengths were involved here.
And I had no idea what your first "Word!!!" was meant to imply.
Hey, maybe that was just my own personal use of the English language going for a walk in the park. I haven't had (m)any Swedes complain about it, have I?
Ann wrote: ↑Sat Jan 22, 2022 4:57 pm
Hey, I always prefer the shorter wavelengths to to be mapped to bluer hues than the longer wavelengths!
The APOD would have been less aesthetically pleasing with the colors reversed, IMO.
Yeah, right. Because people like to think that red is a "hotter" color than blue, so it "makes sense" that the central, hotter part of the jet is red, while the outer, cooler part is blue... right?
Ann wrote: ↑Sat Jan 22, 2022 4:57 pm
I just meant that I had no idea what wavelengths were involved here.
And I had no idea what your first "Word!!!" was meant to imply.
Hey, maybe that was just my own personal use of the English language going for a walk in the park. I haven't had (m)any Swedes complain about it, have I?
Young Star Jet MHO 2147
