A huge bipolar outflow of gas and dust, grown from the tumultuous birth of a double-star system, has formed a cosmic hourglass — and the James Webb Space Telescope imaged the scene in splendiferous detail.
Referred to as Lynds 483, or LBN 483,, this nebulous outflow is located about 650 light years away. It provides an ideal opportunity for the James Webb Space Telescope to learn more about the process of star formation.
(Beverly Lynds was an astronomer who catalogued both bright nebulas – BN – and dark nebulas – DN – in the 1960s)
How does the birth of stars form a nebula like this? Well, stars grow by accreting material from their immediate environs of a gravitationally collapsed cloud of molecular gas.
Yet, paradoxically, they are able to spit some material back out in fast, narrow jets or wider but slower outflows. These jets and outflows clash with gas and dust in the surroundings, creating nebulas like LBN 483.
The jets are formed by material with a rich abundance of varied molecules falling onto young protostars
In the case of LBN 483, there’s not one but two protostars, the main star having a lower mass companion that was only discovered as recently as 2022 by a team led by Erin Cox of Northwestern University using ALMA, the Atacama Large Millimeter/submillimeter Array in Chile.
The fact that there are two stars lurking at the heart of this butterfly-shaped nebula will be crucial, as we shall see.
We can’t see those two protostars in the JWST’s Near-Infrared Camera image they are far too small on the scale of this image but if we could imagine zooming in right to the heart of the nebula, between its two lobes, or “wings,” we would find the two stars snugly ensconced within a dense, doughnut-shaped cloud of gas and dust.
This cloud is supplemented with material from the gaseous, butterfly-shaped nebula beyond; the stars grow from material that accretes onto them from the dusty doughnut.
The jets and outflows are not constant but rather occur in bursts, responding to periods when the baby stars are overfed and belch out some of their accreted material.
Magnetic fields play a crucial role here, directing these outflows of charged particles.
In LBN 483, the JWST is witnessing where these jets and outflows are colliding with both the surrounding nebulous womb but also earlier ejected material.
As the outflows crash into the surrounding material, intricate shapes are formed. The fresh outflow plows through and responds to the density of the material its are encountering.
Source:https://www.space.com/space-exploration/james-webb-space-telescope/this-butterfly-shaped-nebula-owes-its-structure-to-2-chaotic-young-stars
