stars Archives

September 18, 2020September 18, 2020 by Evan Gough

Searching for Phosphorus in Other Stars

A Southwest Research Institute scientist has identified stellar phosphorus as a probable marker in narrowing the search for life in the cosmos. Stars with phosphorus levels similar to the Sun are considered more likely to host rocky planets with the potential to host life as we know it. Image Credit: NASA/JPL-Caltech

The Search for Life can be a lot messier than it sounds. The three words make a nice, tidy title, but what it entails is extraordinarily difficult. How, in this vast galaxy, can we find life and the planets or moons that might host it? We’re barely at the point of either discovering or ruling out other life in our own Solar System.

Finding it somewhere else in the galaxy, even in our own interstellar neighbourhood, is a task so daunting it can be hard to comprehend.

So any time scientists think they’ve found something that can give them an edge in their near-impossible task, it deserves to be talked about.

September 8, 2020September 8, 2020 by Evan Gough

The Strange, Misshapen Orbits of Planet-Forming Disks in a Triple-Star System

ALMA images of the planet-forming disk with misaligned rings around triple star system GW Orionis. The image on the right is made with ALMA data taken in 2017 from Bi et al. The image on the left is made with ALMA data taken in 2018 from Kraus et al. Credit: ALMA (ESO/NAOJ/NRAO), S. Kraus & J. Bi; NRAO/AUI/NSF, S. Dagnello

Whatever we grow up with, we think of as normal. Our single solitary yellow star seems normal to us, with planets orbiting on the same, aligned ecliptic. But most stars aren’t alone; most are in binary relationships. And some are in triple-star systems.

And the planet-forming disks around those three-star systems can exhibit some misshapen orbits.

August 17, 2020August 17, 2020 by Brian Koberlein

The Last Supernovae

Artist's conception of SN2016aps, a candidate pulsational pair instability supernova. The explosion energy of SN2016aps, fueled by the shedding of a massive shell of gas, was ten times that of a normal-sized supernova, making SN2016aps the most massive supernova ever identified. Credit: M. Weiss

A supernova is a powerful event. For a brief moment in time, a star shines as bright as a galaxy, ripping itself apart in a last, desperate attempt to fight against its gravity. While we see supernovae as rare and wondrous things, they are quite common. Based on observations of isotopes in our galaxy, we know that about twenty supernovae occur in the Milky Way every thousand years. These brilliant cosmic flashes fill the universe with heavy elements, and their remnant dust makes up almost everything we see around us. But supernovae won’t keep happening forever. At some point in the far future, the universe will see the last supernova.

July 27, 2020July 28, 2020 by Brian Koberlein

Gamma-Ray Telescopes Can Measure the Diameters of Other Stars

The VERITAS array, an air Cherenkov telescope designed to detect low-energy cosmic rays. Credit: VERITAS

In astronomy, the sharpness of your image depends upon the size of your telescope. When Galileo and others began to view the heavens with telescopes centuries ago, it changed our understanding of the cosmos. Objects such as planets, seen as points of light with the naked eye, could now be seen as orbs with surface features. But even under these early telescopes, stars still appeared as a point of light. While Galileo could see Jupiter or Saturn’s size, he had no way to know the size of a star.

July 14, 2020July 14, 2020 by Evan Gough

1 in 10 Red Giants are Covered in Spots, and They Rotate Surprisingly Quickly

Artist's impression of a red giant star. If the star is in a binary pair, what happens to its sibling? Credit:NASA/ Walt Feimer

Sunspots are common on our Sun. These darker patches are cooler than their surroundings, and they’re caused by spikes in magnetic flux that inhibit convection. Without convection, those areas cool and darken.

Lots of other stars have sunspots, too. But Red Giants (RGs) don’t. Or so astronomers thought.

A new study shows that some RGs do have spots, and that they rotate faster than thought.

June 11, 2020June 11, 2020 by Evan Gough

It Should Be Easiest to Search for Young Earth-like Planets When They’re Completely Covered in Magma

Artist's impression of magma ocean planet. Credit: Mark Garlick

How did Earth evolve from an ocean of magma to the vibrant, life-supporting, blue jewel it is now? In its early years, the Earth was a blistering hot ball of magma. Now, 4.5 billion years later, it’s barely recognizable.

Is it possible to find exoplanets out there in the vast expanse, which are young molten globes much like young Earth was? How many of them can we expect to find? Where will we find them?

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.

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.