star formation Archives

November 16, 2021November 16, 2021 by Evan Gough

New Hubble Image Shows Dark Cocoons Where New Stars are Forming

This image shows knots of cold, dense interstellar gas where new stars are forming. These Free-floating Evaporating Gaseous Globules (frEGGs) were first seen in Hubble’s famous 1995 image of the Eagle Nebula. Because these lumps of gas are dark, they are rarely seen by telescopes. Image Credit: NASA, ESA, and R. Sahai (Jet Propulsion Laboratory); Processing: Gladys Kober (NASA/Catholic University of America)

Star formation is a complex process. But in simple terms, a star forms due to clumps and instabilities in a cloud of molecular hydrogen called a Giant Molecular Cloud (GMC). As more and more gas accumulates and collapses inward, the pressure becomes immense, the gas eventually heats up to millions of degrees, and fusion begins.

But what happens to the gas that remains as the young star forms? Some of it can form a type of dark halo called a frEGG—a free-floating Evaporating Gaseous Globule. And, proving that the Universe is indeed strange, the frEGG itself can contain another stellar embryo. The frEGG can be quite opaque, making it difficult to observe the star’s formation process in all its complexity.

November 3, 2021November 3, 2021 by Evan Gough

What’s Snuffing Out Galaxies Before Their Time?

The VERTICO—Virgo Environment Traced in Carbon Monoxide—Survey observed the gas reservoirs in 51 galaxies in the nearby Virgo Cluster and found that the extreme environment in the cluster was killing galaxies by robbing them of their star-forming fuel. In this composite image, ALMA’s radio wavelength observations of the VERTICO galaxies’ molecular gas disks are magnified by a factor of 20. They are overlaid on the X-ray image of the hot plasma within the Virgo Cluster. Credit: ALMA (ESO/NAOJ/NRAO)/S. Dagnello (NRAO)/Böhringer et al. (ROSAT All-Sky Survey)

In the Milky Way, the formation rate of stars is about one solar mass every year. About 10 billion years ago, it was ten solar masses every year. What happened?

Stars are born in giant molecular clouds (GMCs), and astronomers think that the environment in galaxies affects these clouds and their ability to spawn new stars. Sometimes the environment is so extreme that entire galaxies stop forming new stars.

Astronomers call this “quenching,” and they want to know what causes it.

October 8, 2021October 6, 2021 by Paul M. Sutter

Early Massive Galaxies ran out of gas, Shutting Down Their Star Formation

This image taken by the NASA/ESA Hubble Space Telescope shows the galaxy NGC 4237. Located about 60 million light-years from Earth in the constellation of Coma Berenices (Berenice's Hair), NGC 4237 is classified as a flocculent spiral galaxy. This means that its spiral arms are not clearly distinguishable from each other, as in “grand design” spiral galaxies, but are instead patchy and discontinuous. This gives the galaxy a fluffy appearance, somewhat resembling fluffed cotton. Image Credit: ESA/Hubble & NASA, P. Erwin et al.

Galaxies that formed within the first few billion years after the Big Bang should have lived long, healthy lives. After all, they were born with rich supplies of cold hydrogen gas, exactly the fuel needed to continue star formation. But new observations have revealed “quenched” galaxies that have shut off star formation. And astronomers have no idea why.

October 7, 2021October 6, 2021 by Paul M. Sutter

Are the Burned-Out Remnants of the First Stars all Around us?

An artist's illustration of the Universe's first stars, called Population 3 stars. Pop 3 stars would have been much more massive than most stars today, and would have burned hot and blue. Their lifetimes would've been much shorter than stars like our Sun. Image Credit: Public Domain, https://commons.wikimedia.org/w/index.php?curid=1582286

The first stars to appear in the universe lived fast and died young. Today, none of them likely remain. But their remnants, the black holes and neutron stars, might still wander around the cosmos. Unfortunately, they’re extremely difficult to detect unless they merge, and according to new research the only way to see them would be to conduct an unprecedented survey of the local volume of the universe.

September 3, 2021September 3, 2021 by Matthew Cimone

The Galactic Beauty of Star Formation

Image of Galaxy NGC 3627 located in the constellation LEO. The golden gas glow corresponds to clouds of ionized hydrogen, while the bluish regions reveal the distribution of slightly older stars. Credit: ESO/PHANGS

I’d never seen galaxy images like this before. Nobody had! These images highlight star forming regions in nearby(ish) galaxies. There are still a number of unanswered questions surrounding how star formation actually occurs. To answer those questions, we are observing galaxies that are actively forming stars within giant clouds of gas. Until recently, we didn’t have the resolution needed to clearly image the individual gas clouds themselves. But images released by a project called PHANGS (Physics at High Angular resolution in Nearby GalaxieS) in a collaboration between the European Southern Observatory Very Large Telescope and the Atacama Large millimeter/submillmeter Array (ALMA) have provided never before seen detail of star forming clouds in other galaxies.

This image combines observations of the nearby galaxies NGC 1300, NGC 1087, NGC 3627 (top, from left to right), NGC 4254 and NGC 4303 (bottom, from left to right) taken with the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s Very Large Telescope (VLT). Each individual image is a combination of observations conducted at different wavelengths of light to map stellar populations and warm gas.. Image and Image Description PHANGS/ESO. Original Image

July 7, 2021July 7, 2021 by Andy Tomaswick

One of the Brightest Star-Forming Regions in the Milky Way, Seen in Infrared

Certain parts of the galaxy are more magical than others. There are barren wastelands where barely a particle strays through occasionally, and there are fantastical nebulae that can literally light up the sky. But beyond their good looks, those nebulae hold secrets to understanding some of the most important features of any galaxy – stars. Now, for the first time, a team from the University of Maryland managed to capture a high resolution image of one of the most active star-forming regions in our part of the galaxy. Data from that image are not only spectacular, but can illuminate the details of the star formation process.

June 16, 2021June 16, 2021 by Brian Koberlein

Black Holes don't Just Destroy, They Also Help With Star Formation

A simulation of gas within the Milky Way. Credit: TNG Collaboration/Dylan Nelson

Black holes are the most powerful destructive forces in the universe. They can rip apart a star and scatter its ashes out of the galaxy at nearly the speed of light. But these engines of destruction can also pave the way for new stars to form, as a new study in Nature shows.

June 7, 2021June 7, 2021 by Paul M. Sutter

Star Formation Begins When Clouds of Gas Crash Into Each Other

another seyfert galaxy — The NASA/ESA Hubble Space Telescope has captured this vivid image of spiral galaxy Messier 77 — a galaxy in the constellation of Cetus, some 45 million light-years away from us. The streaks of red and blue in the image highlight pockets of star formation along the pinwheeling arms, with dark dust lanes stretching across the galaxy’s starry centre. The galaxy belongs to a class of galaxies known as Seyfert galaxies, which have highly ionised gas surrounding an intensely active centre.

To trigger star formation, you need to compress a lot of gas into not a lot of volume. To make a lot of stars at once, you need to really pack it in. Until now, astronomers haven’t been sure how to pull this off. But a collection of 20 papers outlines how to do it: make giant clouds of gas crash into each other.

April 5, 2021April 4, 2021 by Paul M. Sutter

There are new Stars Forming Near the Core of the Milky Way Despite the Harsh Environment

ALMA pseudo-color composite image of the gas outflows from baby stars in the Galactic Center region. Gas moving toward us is shown in blue and gas moving away from us is shown in red. Credit: ALMA (ESO/NAOJ/NRAO), Lu et al

The central core of our galaxy is not a friendly place for star formation, and yet new observations have revealed almost four dozen newly-forming systems. These results challenge our understanding of the complicated physics of our galactic heart.

March 26, 2021March 26, 2021 by Scott Alan Johnston

Newly Forming Stars Don’t Blast Away Material as Previously Believed. So Why Do They Stop Growing?

We thought we understood how stars are formed. It turns out, we don’t. Not completely, anyway. A new study, recently conducted using data from the Hubble Space Telescope, is sending astronomers back to the drawing board to rewrite the accepted model of stellar formation.