Stars Archives

June 8, 2020June 9, 2020 by Matt Williams

At the Heart of the Milky Way, Stars Come Close to Each Other All the Time

The core of the Milky Way. Credit: NASA/JPL-Caltech/S. Stolovy (SSC/Caltech)

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At the center of our galaxy resides the Galactic Bulge, a densely-packed region of stars, dust, and gas. Within this massive structure, which spans thousands of light-years, there are an estimated 10 billion stars, most of which are old red giant stars. Because of this density, astronomers have often wondered if a galactic bulge is a likely place to find stars with habitable planets orbiting them.

Essentially, stars that are closely packed together are more likely to experience close encounters with other stars, which can be catastrophic for any planets that orbit them. According to a new study from Columbia University’s Cool Worlds Lab, most stars in the Bulge will experience dozens of close encounters over the course of a billion years, which could have significant implications for long-term habitability in this region.

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June 8, 2020June 8, 2020 by Evan Gough

Much of the Lithium Here on Earth Came from Exploding White Dwarf Stars

A classical novae contains a white dwarf, and a larger companion star in orbit around it. The white dwarf attracts gas from its companion, leading to a massive explosion. Illustration Credit: David Hardy

The Big Bang produced the Universe’s hydrogen, helium, and a little lithium. Since then, it’s been up to stars (for the most part) to forge the rest of the elements, including the matter that you and I are made of. Stars are the nuclear forges responsible for creating most of the elements. But when it comes to lithium, there’s some uncertainty.

A new study shows where much of the lithium in our Solar System and our galaxy comes from: a type of stellar explosion called classical novae.

June 1, 2020June 1, 2020 by Evan Gough

Huge Stars Can Destroy Nearby Planetary Disks

The brilliant tapestry of young stars flaring to life resembles a glittering fireworks display in this Hubble Space Telescope image. The sparkling centerpiece of this fireworks show is a giant cluster of thousands of stars called Westerlund 2. The cluster resides in a raucous stellar breeding ground known as Gum 29, located 20,000 light-years away from Earth in the constellation Carina. Hubble's Wide Field Camera 3 pierced through the dusty veil shrouding the stellar nursery in near-infrared light, giving astronomers a clear view of the nebula and the dense concentration of stars in the central cluster. The cluster measures between six light-years and 13 light-years across. Credits: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI) and the Westerlund 2 Science Team

Westerlund 2 is a star cluster about 20,000 light years away. It’s young—only about one or two million years old—and its core contains some of the brightest and hottest stars we know of. Also some of the most massive ones.

There’s something unusual going on around the massive hot stars at the heart of Westerlund 2. There should be huge, churning clouds of gas and dust around those stars, and their neighbours, in the form of circumstellar disks.

But in Westerlund 2’s case, some of the stars have no disks.

May 29, 2020May 29, 2020 by Evan Gough

A New Kind of Supernova Explosion has been Discovered: Fast Blue Optical Transients

Artist's conception illustrates the differences in phenomena resulting from an "ordinary" core-collapse supernova explosion, an explosion creating a gamma-ray burst, and one creating a Fast Blue Optical Transient. Credit: Bill Saxton, NRAO/AUI/NSF

For the child inside all of us space-enthusiasts, there might be nothing better than discovering a new type of explosion. (Except maybe bigger rockets.) And it looks like that’s what’s happened. Three objects discovered separately—one in 2016 and two in 2018—add up to a new type of supernova that astronomers are calling Fast Blue Optical Transients (FBOT).

May 19, 2020May 19, 2020 by Evan Gough

TESS is Also Helping Astronomers Study Bizarre Pulsating Stars

A conceptual image of the Transiting Exoplanet Survey Satellite. Image Credit: MIT

NASA’s TESS, or Transiting Exoplanet Survey Satellite has one main job: finding exoplanets. But it’s also helping astronomers study a strange type of star that has so far defied thorough explanation. Those stars are Delta Scuti stars, named after their prototype.

May 15, 2020May 15, 2020 by Evan Gough

Was Betelgeuse Formed by Merging Stars?

Betelgeuse was the first star directly imaged -- besides our own Sun, of course. Image obtained by the Hubble Space Telescope. Credit: Andrea Dupree (Harvard-Smithsonian CfA), Ronald Gilliland (STScI), NASA and ESA

Modern humans—or Homo Sapiens—have only been around for about 250,000 years. That’s only the blink of an eye in cosmological terms. As it turns out, the star Betelgeuse may only be about the same age.

A new study explores the idea that Betelgeuse formed from a merger of two stars only a few hundred thousand years ago.

April 21, 2020April 21, 2020 by Evan Gough

Astronomers Watch a Nova Go From Start to Finish for the First Time

Artistic representation of a nova eruption: During a nova eruption a white dwarf sucks matter from its companion star and stores this mass on its surface until the gas pressure becomes extremely high. CREDIT © Nova_by K. Ulaczyk, Warschau Universität Observatorium

A nova is a dramatic episode in the life of a binary pair of stars. It’s an explosion of bright light that can last weeks or even months. And though they’re not exactly rare—there are about 10 each year in the Milky Way—astronomers have never watched one from start to finish.

Until now.

April 18, 2020April 18, 2020 by Brian Koberlein

Betelgeuse Is Bright Again

Artist's impression of Betelgeuse. Credit: ESO/L. Calçada

Everyone’s favorite red supergiant star is bright again. The American Association of Variable Star Observers (AAVSO) has been tracking Betelgeuse as it has gradually returned to its more normal brilliance. As of this writing, it is about 95% of its typical visual brightness. Supernova fans will have to wait a bit longer.

April 4, 2020April 4, 2020 by Paul M. Sutter

Astronomers are hoping to see the very first stars and galaxies in the Universe

The epoch of reionization was when light from the first stars could travel through the early Universe. At this time, galaxies began assembling, as did black holes. Why did some early galaxies have ancient stars? That's a question JWST will help answer. Credit: Paul Geil & Simon Mutch/The University of Melbourne

Sometimes it’s easy being an astronomer. When your celestial target is something simple and bright, the game can be pretty straightforward: point your telescope at the thing and just wait for all the juicy photons to pour on in.

But sometimes being an astronomer is tough, like when you’re trying to study the first stars to appear in the universe. They’re much too far away and too faint to see directly with telescopes (even the much-hyped James Webb Space Telescope will only be able to see the first galaxies, an accumulation of light from hundreds of billions of stars). To date, we don’t have any observations of the first stars, which is a major bummer.

March 10, 2020March 10, 2020 by Nancy Atkinson

It Looks Like Betelgeuse was Dimming Because it was Dusty After All

Betelgeuse before and after dimming — This comparison image shows the star Betelgeuse before and after its unprecedented dimming. The observations, taken with the SPHERE instrument on ESO’s Very Large Telescope in January and December 2019, show how much the star has faded and how its apparent shape has changed.

It’s been said that dust built the Universe. And it turns out dust may be the culprit for building up what are likely false hopes of soon witnessing a massive supernova for the star Betelgeuse.