Rogue star crashes cosmic baby shower

Rogue star crashes cosmic baby shower

Rogue star crashes cosmic baby shower

Astronomers recently ran into a star who was hiding a secret. A protostar in a distant stellar nursery called the Aquila Rift had a distorted magnetic field, and researchers weren’t sure why. Behind a veil of dust, astronomers found the culprit: a baby star locked in a gravitational embrace with the protostar, hidden in a cosmic nest.

The discovery will help astronomers find more such star pairs by searching for peculiar magnetic fields, which can act as a beacon toward baby stars. The discovery also hints at how binary systems originate. That’s a big part of understanding the universe, because half of all sun-like stars in space occur in two.

Astronomer Erin Guilfoil Cox of Northwestern University led the team that peered into L483, the cloud at the heart of the study. Cox and colleagues turned to several observatories, including the aircraft-based Stratospheric Observatory for Infrared Astronomy (SOFIA), the Atacama Large Millimeter Array (ALMA) Radio Telescope in Chile and the Pico dos Dias Observatory in Brazil.

A paper published Tuesday in The Astrophysical Journal details the findings.

Here’s the background — Binary stars are “notoriously difficult to observe in their early stages of life,” says Guilfoil Cox inverse† ‘That’s because they’re shrouded in this gas and dust, so they’re quite invisible to most telescopes. We don’t know much about their very early stages of life.”

Deaths from stars are huge, bursting out like supernovae in the blink of an eye, producing nebulae many times larger than the diameter of the abandoned star.

But baby stars are harder to track. The cosmic cloud of dust and gas, which coalesces to become a new protostar, also forms a haze that obscures a youngster from astronomers. Baby stars also grow slowly, with only minor changes over a lifetime.

Fortunately, astronomers may have found a new detour to learn more about these early chapters. Guilfoil Cox’s team found that the journey from a previously unknown baby star to another protostar may have distorted a magnetic field.

Now astronomers want to find more examples like this, and if they do, they’ll have a whole new way of learning how baby stars turn into their adult selves.

What’s new – A magnetic field is a force field. We are probably most familiar with the way it directs a compass to the North and South Poles, where the magnetic field lines enter our planet. The cores of both the Earth and the Sun generate magnetic fields, but the Big Bang may have done just that, with lingering effects. Strangely enough, mysterious magnetic field lines run through all parts of our galaxy, including the stellar nursery that Guilfoil Cox observed.

It turns out that the processes that created and carried the newly discovered baby star — initially hidden in the nursery of another known protostar — had twisted a magnetic field line.

Why it matters – Learning how stars form can help us learn more about the solar system and understand our origins.

“Stars are the basic unit of the universe,” says Guilfoil Cox. The forces that produce stars affect how their planets form, and together stars and planets form galaxies. Therefore, understanding the life cycles of stars is critical to astrophysics.

An illustration of the development of a baby star. A massive young star produces beams of charged particles that shoot from its poles as its magnetic field is overwhelmed by the amount of material it has pulled from the envelope, the dark orange region of star material seen below right.B. Saxton, NRAO/AUI/NSF

What they did – Astronomers looked at L843, an “isolated star-forming region” — that just means this cosmic nursery isn’t full of young stars.

They took a comprehensive survey of this area, from about 10,000 Earth-Sun distances (or astronomical units), then zoomed in on size, starting first with what’s known as a molecular cloud, down to a shell of material, down to a disk. , then to a protostar, ending at about 1,000 astronomical units. These structures are getting denser on smaller scales.

They noticed a magnetic field that ran parallel to an outflow of discarded material that made stars, creating jets. When astronomers zoomed in on this scene, they saw the twist.

“It doesn’t seem likely that it would happen,” says Guilfoil Cox. The field should appear more disordered the more they zoomed in on the scene, when observing smaller scales. But they saw that this field was not scattered.

“So we zoomed in even further with the ALMA telescope in Chile, and we see that the system we were looking at is actually two stars. And they’re pretty close to each other.”

“We thought, ‘oh, this is interesting,'” she says. “We thought this was a single star when we first proposed to observe it.”

The yellow area at the top of this image is a cloud of material from which multiple stars can form. The center of the image shows three pockets of dust and gas, called protostellar clouds, which will collapse to form three stars. At the bottom, we zoom in on one of these future stars to see a disk condensing into the protostar at the center of the disk. B. Saxton, NRAO/AUI/NSF

What they discovered – One possible explanation is that the two baby stars, now about 30 astronomical units apart — the distance between the sun and Pluto — were once much farther apart when they formed.

Guilfoil Cox says computer simulations show that binary stars can form far apart — more than 500 astronomical units apart — and then gradually move closer together.

“If there’s a change in the dynamics of the system very close together, on the scales of the protostars, it can shift the direction of the magnetic field.”

What’s next – “We think we can use the magnetic field signature to determine the formation history of the binary number,” says Guilfoil Cox.

To prove that a magnetic field signature could be a new astronomical tool, researchers need to collect a statistical sample showing other similar cases to Guilfoil Cox’s work. The monster will have to be on the scale of envelopes, those tight but undulating regions of stellar yolk that surround and grow protostars.

Guilfoil Cox will examine a number of young stars to see if there are binaries there, while also looking at the morphology of their magnetic fields using the TolTEC instrument at the Large Millimeter Telescope in Mexico.

The team looks forward to the “really exciting time” when they can use newer, higher-sensitivity telescopes to look into these stellar nursery rooms like never before.