Compared to the lifespan of stars, human lives are pretty short. Stars such as Betelgeuse (in Orion) live for millions of years. Others exist for billions of years. We (if we’re lucky) get maybe 100 years (more or less). So, to us, stars don’t appear to change much over our lifetimes, unless they blow up as supernovae. But, what about over the course of 20 or 30 successive lifetimes?Continue reading “Just 2,000 Years Ago, Betelgeuse Was Yellow, Not Red”
Planetary nebulae are short-lived “leftovers” of sun-like stars. Most of these “star ghosts” only last—at most—about 25,000 years. Usually, their clouds of debris disperse so broadly that they fade out fairly quickly. However, there’s one that has lasted at least 70,000 years. That makes it a “grande dame” of planetary nebulae.Continue reading “Astronomers Find the Oldest Planetary Nebula”
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When you look at a region of the sky where stars are born, you see a cloud of gas and dust and a bunch of stars. It’s really a beautiful sight. In most places, the stars all end up being about the same mass. That mass is probably the most important factor you want to know about it. It directs how long the star will live and what its future will be like. But, what determines its mass and the mass of its siblings in a stellar nursery? Is there some governing force that tells them how massive they’ll be? It turns out that the stars do it for themselves.Continue reading “In Wildly Different Environments, Stars End Up Roughly the Same”
Our Sun is doomed. Billions of years from now, the Sun will deplete its hydrogen fuel and swell to a red giant before becoming a white dwarf. It’s a well-known story, and one astronomers have understood for decades. Now, thanks to the latest data from Gaia, we know the Sun’s future in much greater detail.Continue reading “Thanks to Gaia we Know Exactly how and When the Sun Will die”
What happens when a massive star dies? Conventional wisdom (and observational evidence) say that it can collapse to form a “stellar-mass” black hole. Astronomers detect black holes by the X-ray emissions they emit.
But, what if the black hole isn’t giving off high levels of X-ray emissions? Then, it could be a very rare object indeed: a dormant black hole. Not many of these have been seen. So, it’s exciting to know that a team of astronomers has found one. It’s called VFTS 243. They detected it in Very Large Telescope observations of stars in the Tarantula Nebula, in the neighboring Large Magellanic Cloud.Continue reading “A Dormant Black Hole has Been Discovered Just Outside the Milky Way”
Making a 3D map of our galaxy would be easier if some stars behaved long enough to get good distances to them. However, red supergiants are the frisky kids on the block when it comes to pinning down their exact locations. That’s because they appear to dance around, which makes pinpointing their place in space difficult. That wobble is a feature, not a bug of these massive old stars and scientists want to understand why.
So, as with other challenging objects in the galaxy, astronomers have turned to computer models to figure out why. In addition, they are using Gaia mission position measurements to get a handle on why red supergiants appear to dance.Continue reading “Red Supergiant Stars Bubble and Froth so Much That Their Position in the Sky Seems to Dance Around”
A couple of years ago, Betelgeuse generated much interest when it started dimming. That caught the attention of astronomers worldwide, who tried to understand what was happening. Was it about to go supernova?
Evidence showed that dust was the most likely culprit for the red supergiant’s dimming, though there are still questions. A new study shows that the star was behaving strangely just before the dimming.Continue reading “Astronomers Caught Betelgeuse Just Before it Started Dimming and Might Have Seen a Pressure Wave Rippling Through its Atmosphere”
Millions of stars that can grow up to 620 million miles in diameter, known as ‘red giants,’ exist in our galaxy, but it has been speculated for a while that there are some that are possibly much smaller. Now a team of astronomers at the University of Sydney have discovered several in this category and have published their findings in the journal Nature Astronomy.
Continue reading “Slimmed Down Red Giants Had Their Mass Stolen By a Companion Star”
“It’s like finding Wally… we were extremely lucky to find about 40 slimmer red giants, hidden in a sea of normal ones. The slimmer red giants are either smaller in size or less massive than normal red giants.”PhD candidate Mr Yaguang Li from the University of Sydney, as quoted from the source article.
When young stars coalesce out of a cloud of molecular hydrogen, a disk of leftover material called a protoplanetary disk surrounds them. This disk is where planets form, and astronomers are getting better at peering into those veiled environments and watching embryonic worlds take shape. But young stars aren’t the only stars with disks of raw material rotating around them.
Some old, dying stars also have disks. Can a second generation of planets form under those conditions?Continue reading “A Second Generation of Planets can Form Around a Dying Star”
It’s another first for astronomy.
For the first time, a team of astronomers have imaged in real-time as a red supergiant star reached the end of its life. They watched as the star convulsed in its death throes before finally exploding as a supernova.
And their observations contradict previous thinking into how red supergiants behave before they blow up.Continue reading “Astronomers Watch a Star Die and Then Explode as a Supernova”