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Baby star's first scream


StringJunky

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Imagine you could go back in time 4.6 billion years and take a picture of our Sun just as it was being born. What would it look like?

Well, you can get a clue from this glorious new image acquired by the James Webb Space Telescope (JWST).

Towards the centre of this object, called HH212, is a star coming into existence that is probably no more than 50,000 years old.

The scene would have looked much the same when our Sun was a similar age.

You can't actually see the glow from the protostar itself because it's hidden within a dense, spinning disc of gas and dust.

All you get are the pinky-red jets that it's shooting out in polar opposite directions.

_131585876_hh212_jwst_full_20231030.jpg.

HH212 is sited in Orion, close to the three brilliant stars that make up the "belt" of the mythical hunter that gives the constellation its name. The distance from Earth is about 1,300 light-years.

Physics suggests those dramatic outflows of gas are the means by which the nascent star regulates its birthing.

"As the blobby ball of gas at the centre compacts down, it rotates. But if it rotates too fast, it will fly apart, so something has to get rid of the angular momentum," explained Prof Mark McCaughrean...... https://www.bbc.co.uk/news/science-environment-67243772

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2 hours ago, StringJunky said:

Imagine you could go back in time 4.6 billion years and take a picture of our Sun just as it was being born. What would it look like?

Well, you can get a clue from this glorious new image acquired by the James Webb Space Telescope (JWST).

Towards the centre of this object, called HH212, is a star coming into existence that is probably no more than 50,000 years old.

The scene would have looked much the same when our Sun was a similar age.

You can't actually see the glow from the protostar itself because it's hidden within a dense, spinning disc of gas and dust.

All you get are the pinky-red jets that it's shooting out in polar opposite directions.

_131585876_hh212_jwst_full_20231030.jpg.

HH212 is sited in Orion, close to the three brilliant stars that make up the "belt" of the mythical hunter that gives the constellation its name. The distance from Earth is about 1,300 light-years.

Physics suggests those dramatic outflows of gas are the means by which the nascent star regulates its birthing.

"As the blobby ball of gas at the centre compacts down, it rotates. But if it rotates too fast, it will fly apart, so something has to get rid of the angular momentum," explained Prof Mark McCaughrean...... https://www.bbc.co.uk/news/science-environment-67243772

What a terrible explanation. It ascribes intent to the star and fails to explain why the jets arise. The BBC so often these days treats its audience like children when it comes to science.

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From the JWT site:

STScI-01H9NX6AP9G1W51XNMTHD41YJE.jpg

Summary

Infrared capabilities map out molecular structure of outflow
NASA’s James Webb Space Telescope has captured a high-resolution look at Herbig-Haro 211 (HH 211), a bipolar jet traveling through interstellar space at supersonic speeds. At roughly 1,000 light-years away from Earth in the constellation Perseus, the object is one of the youngest and nearest protostellar outflows, making it an ideal target for Webb.

Herbig-Haro (HH) objects are luminous regions surrounding newborn stars, formed when stellar winds or jets of gas spewing from these newborn stars form shock waves colliding with nearby gas and dust at high speeds. This image of HH 211 from NASA’s James Webb Space Telescope reveals an outflow from a Class 0 protostar, an infantile analog of our Sun when it was no more than a few tens of thousands of years old and with a mass only 8% of the present-day Sun. (It will eventually grow into a star like the Sun.)

Infrared imaging is powerful in studying newborn stars and their outflows, because such stars are invariably still embedded within the gas from the molecular cloud in which they formed. The infrared emission of the star’s outflows penetrates the obscuring gas and dust, making a Herbig-Haro object like HH 211 ideal for observation with Webb’s sensitive infrared instruments. Molecules excited by the turbulent conditions, including molecular hydrogen, carbon monoxide, and silicon monoxide, emit infrared light that Webb can collect to map out the structure of the outflows.

https://webbtelescope.org/contents/news-releases/2023/news-2023-141

 

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2 hours ago, swansont said:

The specifics of the mechanism might be missing, but it clearly states that the jets arise because the system needs to shed angular momentum. (that was an epiphany for me when I first learned it)

But what does it mean to say the system “needs” to shed angular momentum? That suggests it has intent to do so, in order to keep itself together, which is not science. OK, I get that if it did not, it would not hold together, but why should these jets so conveniently arise?

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Quote

The Giant Herbig-Haro Flow HH 212 and Associated Star Formation


Bo Reipurth, C.J. Davis, John Bally, A.C. Raga, B.P. Bowler, T.R. Geballe, Colin Aspin, Hsin-Fang Chiang


The bipolar jet HH 212, among the finest collimated jets known, has so far been detected only in near-infrared H2 emission. Here we present deep optical images that show two of the major bow shocks weakly detected in optical [SII] emission, as expected for a bona fide Herbig-Haro jet. We present widefield H2 images which reveal two more bow shocks located symmetrically around the source and along the main jet axis. Additionally, examination of Spitzer 4.5 μm images reveals yet another bright bow shock further to the north along the jet axis; no corresponding bow shock is seen to the south. In total, the HH 212 flow has an extent of 1050 arcsec, corresponding to a projected dimension of 2.0 pc. HH 212 thus joins the growing group of parsec-scale Herbig-Haro jets. Proper motion measurements indicate a velocity of about 170 km/sec, highly symmetric around the source, with an uncertainty of ∼30 km/sec, suggesting a probable age of the giant HH 212 flow of about 7000 yr. The jet is driven by a deeply embedded source, known as IRAS 05413-0104. We draw attention to a Spitzer near- and mid-infrared source, which we call IRS-B, located only 7 arcsec from the driving source, towards the outskirts of the dense cloud core. Infrared photometry and spectroscopy suggests that IRS-B is a K-type star with a substantial infrared excess, except that for an extinction of AV = 44 the star would have only a weakinfrared excess, and so in principle it could be a K-giant at a distance of about 2 kpc. https://arxiv.org/abs/1911.05877

2019 paper from around the time when it was discovered.

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