Space and astronomy news
Astronomers have a new tool to help them understand giant stars. It’s a detailed study of the precise temperatures and sizes of 191 giant stars. The authors of the work say that it’ll serve as a standard reference on giant stars for years to come.
It’ll also shed some light on what the Sun will go through late in its life.
Continue reading “Giant Stars and the Ultimate Fate of the Sun”
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.
Continue reading “New Hubble Image Shows Dark Cocoons Where New Stars are Forming”
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.
Continue reading “What’s Snuffing Out Galaxies Before Their Time?”
In April 2021 Hubble released its 31st-anniversary image. It’s a portrait of AG Carinae, one of the most luminous stars in the entire Milky Way. AG Carinae is in a reckless struggle with itself, periodically ejecting matter until it reaches stability sometime in the future.
Thanks to the Hubble, we get to watch the brilliant struggle.
Continue reading “Hubble Reveals the Final Stages of a Dying Star”
Supermassive black holes (SMBH) reside in the center of galaxies like the Milky Way. They are mind-bogglingly massive, ranging from 1 million to 10 billion solar masses. Their smaller brethren, intermediate-mass black holes (IMBH), ranging between 100 and 100,000 solar masses, are harder to find.
Astronomers have spotted an intermediate-mass black hole destroying a star that got too close. They’ve learned a lot from their observations and hope to find even more of these black holes. Observing more of them may lead to understanding how SMBHs got so massive.
Continue reading “Astronomers Discover an Intermediate-Mass Black Hole as it Destroys a Star”
At the beginning of 2020, the red giant star Betelgeuse started to dim significantly. Betelgeuse has been known to vary in brightness, but this one was unusual. It grew much dimmer than usual, and for a longer period. Since Betelgeuse is a star at the end of its life, it led some to speculate that perhaps it would go supernova. Astronomers didn’t think that was likely, and of course, Betelgeuse didn’t explode, and gradually its usual brightness returned. But astronomers were puzzled as to why Betelgeuse grew so dim.
Continue reading “Betelgeuse's Mysterious Dimming Solved. It was… Dust”
Main sequence stars fuse hydrogen in their cores. It’s how they produce the energy they need to shine and keeps them from collapsing under their own weight. As hydrogen is fused into helium, there is less hydrogen available in the core. This can pose a challenge for large stars. They need to fuse a tremendous amount of hydrogen to keep shining, and they can’t do that when core hydrogen is depleted. Fortunately, they can solve this problem by mixing more hydrogen into their core. A new study in Nature Astronomy shows us how this mixing happens.
Continue reading “Massive Stars Mix Hydrogen in Their Cores, Causing Them to Pulse Every few Hours or Days”
Older stars should slow down, but new observations reveal that they have just as much of a spring in their step as their younger cousins. Astronomers suspect that complex interactions with the star’s magnetic field might be to blame.
Continue reading “Older Stars Rotate Faster Than Expected”
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.
Continue reading “Newly Forming Stars Don’t Blast Away Material as Previously Believed. So Why Do They Stop Growing?”
The disappearance of a star can take many forms. It could go supernova. It could turn into a black hole. Or it could just fade away quietly. Sometimes, the last of these is actually the most interesting to observe. That is the case for one of the largest stars ever found – VY Canis Majoris, a red supergiant approximately 3840 light years away in the Canis Major constellation.
Continue reading “VY Canis Majoris is “Like Betelgeuse on Steroids””