Stars Archives

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.

February 25, 2020February 25, 2020 by Brian Koberlein

Betelgeuse Is Brightening Again

A simulation of Betelgeuse. Credit: Bernd Freytag

The latest observations of Betelgeuse show that the star is now beginning to slowly brighten. No supernova today! Nothing to see, better luck next time.

Despite some of the hype, this behavior is exactly what astronomers expected. Betelgeuse is a very different star from our Sun. While our Sun is a main-sequence star in its prime of life, Betelgeuse is a red giant star on the verge of death. But the death of a star is not a simple process.

February 20, 2020February 20, 2020 by Evan Gough

Both Stars in This Binary System Have Accretion Disks Around Them

Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. What has caused this star — and others like it — to dramatically brighten? [NASA/JPL-Caltech] — Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. Credit: NASA/JPL-Caltech

Stars exhibit all sorts of behaviors as they evolve. Small red dwarfs smolder for billions or even trillions of years. Massive stars burn hot and bright but don’t last long. And then of course there are supernovae.

Some other stars go through a period of intense flaring when young, and those young flaring stars have caught the attention of astronomers. A team of researchers are using the Atacama Large Millimeter/sub-millimeter Array (ALMA) to try to understand the youthful flaring. Their new study might have found the cause, and might have helped answer a long-standing problem in astronomy.

January 22, 2020January 22, 2020 by Evan Gough

Betelgeuse is Continuing to Dim! It’s Down to 1.506 Magnitude

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

Betelgeuse keeps getting dimmer and everyone is wondering what exactly that means. The star will go supernova at the end of its life, but that’s not projected to happen for tens of thousands of years or so. So what’s causing the dimming?

December 19, 2019December 19, 2019 by Evan Gough

Without a Magnetosphere, Planets Orbiting Flare Stars Don’t Stand a Chance

An artist's conception of a superflare event, on a dwarf star. Image credit: Mark Garlick/University of Warwick

Earthlings are fortunate. Our planet has a robust magnetic shield. Without out magnetosphere, the Sun’s radiation would’ve probably ended life on Earth before it even got going. And our Sun is rather tame, in stellar terms.

What’s it like for exoplanets orbiting more active stars?

November 22, 2019November 26, 2019 by Matt Williams

Of the Two Stars in Alpha Centauri, One is Probably More Habitable than the Other

Artist's impression of a hypothetical planet orbiting the star Alpha Centauri B, a member of the triple star system that is the closest to Earth. Credit: ESO

In the past, the number of known exoplanets has exploded, with 4093 confirmed detections so far (and another 4,727 candidates awaiting confirmation). With the discovery of so many planets that are dozens, hundreds, or even thousands of light years away, a great deal of attention has understandably been directed to our nearest stellar neighbors. Could planets be right next door, with the possibility of life being there as well?

While a potentially-habitable planet was recently discovered around Proxima Centauri (Proxima b), Alpha Centauri remains something of a question mark. But thanks to a recent study from the Georgia Institute of Technology (GIT), we might be getting closer to determining if this neighboring system supports life. In a twist, the study revealed that one of the stars in the binary system is more likely to be habitable than the other.

November 15, 2019November 15, 2019 by Evan Gough

Tatooines everywhere? Many of the Exoplanets Already Discovered are in Multi-Star Systems

These images show some of the exoplanet host stars with companion stars (B, C) that were found during the project. The images are RGB composite images taken with the Panoramic Survey Telescope and Rapid Response System (PanSTARRS) in the y- (960 nm), i- (760 nm), and g-band (480 nm). The image in the middle shows a hierarchical triple star system. Image: Mugrauer, PanSTARRS

Right now, we know of about 4,000 confirmed exoplanets, mostly thanks to the Kepler mission. TESS, the Transiting Exoplanet Survey Satellite, will likely raise that 4000 by a lot. But what about the stars that all of these planets orbit?

A new study from the Astrophysical Institute and University Observatory of the University of Jena identified over 200 exoplanets that exist in multiple star systems. The study is part of the effort to understand how host stars shape the formation and evolution of planets.

November 5, 2019November 5, 2019 by Matt Williams

The First Stars Formed Very Quickly

Credit: Max Planck Institute for Astronomy

Ever since astronomers realized that the Universe is in a constant state of expansion and that a massive explosion likely started it all 13.8 billion years ago (the Big Bang), there have been unresolved questions about when and how the first stars formed. Based on data gathered by NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) and similar missions, this is believed to have happened about 100 million years after the Big Bang.

Much of the details of how this complex process worked have remained a mystery. However, new evidence gathered by a team led by researchers from the Max Planck Institute for Astronomy indicates that the first stars must have formed rather quickly. Using data from the Magellan Telescopes at Las Campanas Observatory, the team observed a cloud of gas where star formation was taking place just 850 million years after the Big Bang.

September 17, 2019September 17, 2019 by Evan Gough

The Most Massive Neutron Star has been Found. It’s ALMOST the Most Massive Neutron Star That’s Even Possible

Artist's illustration of a rotating neutron star, the remnants of a super nova explosion. Credit: NASA, Caltech-JPL

Neutron stars are the end-state of massive stars that have spent their fuel and exploded as supernovae. There’s an upper limit to their mass, because a massive enough star won’t become a neutron star; it’ll become a black hole. But finding that upper mass limit, or tipping point, between a star that becomes a black hole and one that becomes a neutron star, is something astronomers are still working on.

Now a new discovery from astronomers using the National Science Foundation’s (NSF) Green Bank Telescope (GBT) have found the most massive neutron star yet, putting some solid data in place about the so-called tipping point.

September 5, 2019September 5, 2019 by Evan Gough

This Star Has Reached the End of its Life

This Picture of the Week from the NASA/ESA Hubble Space Telescope shows NGC 5307, a planetary nebula which lies about 10000 light years from Earth. It can be seen in the constellation Centaurus (The Centaur), which can be seen primarily in the southern hemisphere. A planetary nebula is the final stage of a Sun-like star. As such, planetary nebulae allow us a glimpse into the future of our own Solar System. A star like our Sun will, at the end of its life, transform into a red giant. Stars are sustained by the nuclear fusion that occurs in their core, which creates energy. The nuclear fusion processes constantly try to rip the star apart. Only the gravity of the star prevents this from happening. At the end of the red giant phase of a star, these forces become unbalanced. Without enough energy created by fusion, the core of the star collapses in on itself, while the surface layers are ejected outward. After that, all that remains of the star is what we see here: glowing outer layers surrounding a white dwarf star, the remnants of the red giant star’s core. This isn’t the end of this star’s evolution though — those outer layers are still moving and cooling. In just a few thousand years they will have dissipated, and all that will be left to see is the dimly glowing white dwarf.

About 10,000 light years away, in the constellation Centaurus, is a planetary nebula called NGC 5307. A planetary nebula is the remnant of a star like our Sun, when it has reached what can be described as the end of its life. This Hubble image of NGC 5307 not only makes you wonder about the star’s past, it makes you ponder the future of our very own Sun.