Small, Tough Planets can Survive the Death of Their Star

An asteroid torn apart by the strong gravity of a white dwarf has formed a ring of dust particles and debris orbiting the Earth-sized burnt out stellar core. Image Credit: University of Warwick/Mark Garlick

Sad fact of the Universe is that all stars will die, eventually. And when they do, what happens to their babies? Usually, the prognosis for the planets around a dying star is not good, but a new study says some might in fact survive.

A group of astronomers have taken a closer look at what happens when stars, like our Sun for instance, become white dwarfs late in their lives. As it turns out, denser planets like Earth might survive the event. But, only if they’re the right distance away.

Continue reading “Small, Tough Planets can Survive the Death of Their Star”

Some of Earth’s Gold Came From Two Neutron Stars That Collided Billions of Years Ago

Collisions of neutron stars produce powerful gamma-ray bursts – and heavy elements like gold (Credit: Dana Berry, SkyWorks Digital, Inc.)

For about a century now, scientists have theorized that the metals in our Universe are the result of stellar nucleosynthesis. This theory states that after the first stars formed, heat and pressure in their interiors led to the creation of heavier elements like silicon and iron. These elements not only enriched future generations of stars (“metallicity”), but also provided the material from which the planets formed.

More recent work has suggested that some of the heaviest elements could actually be the result of binary stars merging. In fact, a recent study by two astrophysicists found that a collision which took place between two neutron stars billions of years ago produced a considerable amount of some of Earth’s heaviest elements. These include gold, platinum and uranium, which then became part of the material from which Earth formed.

Continue reading “Some of Earth’s Gold Came From Two Neutron Stars That Collided Billions of Years Ago”

What Will the James Webb Space Telescope See? A Whole Bunch of Dust, That’s What

With its helical appearance resembling a snail’s shell, this reflection nebula seems to spiral out from a luminous central star in this new NASA/ESA Hubble Space Telescope image. The star in the centre, known as V1331 Cyg and located in the dark cloud LDN 981 — or, more commonly, Lynds 981 — had previously been defined as a T Tauri star. A T Tauri is a young star — or Young Stellar Object — that is starting to contract to become a main sequence star similar to the Sun. What makes V1331Cyg special is the fact that we look almost exactly at one of its poles. Usually, the view of a young star is obscured by the dust from the circumstellar disc and the envelope that surround it. However, with V1331Cyg we are actually looking in the exact direction of a jet driven by the star that is clearing the dust and giving us this magnificent view. This view provides an almost undisturbed view of the star and its immediate surroundings allowing astronomers to study it in greater detail and look for features that might suggest the formation of a verylow-mass object in the outer circumstellar disc.

When it comes to the first galaxies, the James Webb Space Telescope will attempt to understand the formation of those galaxies and their link to the underlying dark matter. In case you didn’t know, most of the matter in our universe is invisible (a.k.a. “dark”), but its gravity binds everything together, including galaxies. So by studying galaxies – and especially their formation – we can get some hints as to how dark matter works. At least, that’s the hope. It turns out that astronomy is a little bit more complicated than that, and one of the major things we have to deal with when studying these distant galaxies is dust. A lot of dust.

That’s right: good old-fashioned dust. And thanks to some fancy simulations, we’re beginning to clear up the picture.

Continue reading “What Will the James Webb Space Telescope See? A Whole Bunch of Dust, That’s What”

Voyager and Pioneer’s Grand Tour of the Milky Way

An artist's concept of Voyager 1's view of the Solar System. Voyager 1 is one of our first interstellar probes, though it's an inadvertent one. It has no particular destination. Credit: NASA, ESA, and J. Zachary and S. Redfield (Wesleyan University); Artist's Illustration Credit: NASA, ESA, and G. Bacon (STScI).

During the early 1990s, NASA’s Pioneer 10 and 11 probes became the first robotic missions to venture beyond Neptune. In 2012 and 2018, the Voyager 1 and 2 missions went even farther by crossing the heliopause and entering interstellar space. Eventually, these probes may reach another star system, where their special cargo (the Pioneer Plaques and the Golden Records) could find their way into the hands of another species.

Which raises an important question: where might these spacecraft eventually wander? To address this, Coryn Bailer-Jones of the Max Planck Institute for Astronomy and Davide Farnocchia of NASA’s Jet Propulsion Laboratory recently conducted a study that examined which star systems the Voyager and Pioneer probes will likely encounter as they drift through the Milky Way over the next few million years…

Continue reading “Voyager and Pioneer’s Grand Tour of the Milky Way”

This Star has been Kicked Out of the Milky Way. It Knows What It Did.

Researchers from the University of Michigan confirm that a runaway star was ejected from the Milky Way's disk rather than the galactic core. Image Credit: Kohei Hattori
Researchers from the University of Michigan confirm that a runaway star was ejected from the Milky Way's disk rather than the galactic core. Image Credit: Kohei Hattori

Every once in a while, the Milky Way ejects a star. The evicted star is typically ejected from the chaotic area at the center of the galaxy, where our Super Massive Black Hole (SMBH) lives. But at least one of them was ejected from the comparatively calm galactic disk, a discovery that has astronomers rethinking this whole star ejection phenomenon.

Continue reading “This Star has been Kicked Out of the Milky Way. It Knows What It Did.”

Massive Photons Could Explain Dark Matter, But Don’t

A computer simulation of the distribution of matter in the universe. Orange regions host galaxies; blue structures are gas and dark matter. Credit: TNG Collaboration

I’ll be the first to admit that we don’t understand dark matter. We do know for sure that something funny is going on at large scales in the universe (“large” here meaning at least as big as galaxies). In short, the numbers just aren’t adding up. For example, when we look at a galaxy and count up all the hot glowing bits like stars and gas and dust, we get a certain mass. When we use any other technique at all to measure the mass, we get a much higher number. So the natural conclusion is that not all the matter in the universe is all hot and glowy. Maybe some if it is, you know, dark.

But hold on. First we should check our math. Are we sure we’re not just getting some physics wrong?

Continue reading “Massive Photons Could Explain Dark Matter, But Don’t”

Eta Carinae is Getting Brighter Because a Dust Cloud was Blocking our View

Eta Carinae, one of the most massive stars known. Image credit: NASA
Eta Carinae, one of the most massive stars known. Credit: NASA

In addition to being one of the most beautiful and frequently photographed objects in the night sky, Eta Carinae also has also had the honor of being one of the sky’s most luminous stars for over a century and a half. In addition, it has been a scientific curiosity since its giant ejected nebula (Homunculus) contains information about its parent star.

It is therefore sad news that within a decade or so, we will no longer be able to see the Homunculus nebula clearly. That was the conclusion reached in a new study by an international team of researchers. According to their findings, the nebula will be obscured by the growing brightness of Eta Carinae itself, which will be ten times brighter by about 2036.

Continue reading “Eta Carinae is Getting Brighter Because a Dust Cloud was Blocking our View”

A New Technique to Figure Out How Old Stars Are

Embry-Riddle researchers used data captured by the Gaia satellite (shown here in an artist’s impression) to determine the ages of stars. Credit: European Space Agency – D. Ducros, 2013
Embry-Riddle researchers used data captured by the Gaia satellite (shown here in an artist’s impression) to determine the ages of stars. Credit: European Space Agency – D. Ducros, 2013

Our understanding of the universe, and of the Milky Way, is built on an edifice of individual pieces of knowledge, all related to each other. But each of those pieces is only so accurate. The more accurate we can make one of the pieces of knowledge, the more accurate our understanding of the whole thing is.

The age of stars is one such piece. For years, astronomers have used a method of determining the age of stars that has a 10% to 20% margin of error. Now, a team of scientists from Embry-Riddle Aeronautical University has developed a new technique to determine the age of stars with a margin of error of only 3% to 5%.

Continue reading “A New Technique to Figure Out How Old Stars Are”

Bizarre Double Star System Flipped its Planetary Disk on its Side

This illustration shows a binary star surrounded by a thick disc of material in a polar orbit. Copyright and credit: University of Warwick/Mark Garlick

Astronomers theorize that when our Sun was still young, it was surrounded by a disc of dust and gas from which the planets eventually formed. It is further theorized that the majority of stars in our Universe are initially surrounded in this way by a “protoplanetary disk“, and that in roughly 30% of cases, these disks will go on to become a planet or system of planets.

Ordinarily, these disks are thought to orbit around the equatorial band (aka. the ecliptic) of a star or system of stars. However, new research conducted by an international group of scientists has discovered the first example of a binary star system where the orientation was flipped and the disk now orbits the stars around their poles (perpendicular to the ecliptic).

Continue reading “Bizarre Double Star System Flipped its Planetary Disk on its Side”

Habitable Planets Around Red Dwarf Stars Might not get Enough Photons to Support Plant Life

Artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB is visible to the upper right of Proxima itself. Credit: ESO

In recent years, the number of extra-solar planets discovered around nearby M-type (red dwarf stars) has grown considerably. In many cases, these confirmed planets have been “Earth-like“, meaning that they are terrestrial (aka. rocky) and comparable in size to Earth. These finds have been especially exciting since red dwarf stars are the most common in the Universe – accounting for 85% of stars in the Milky Way alone.

Unfortunately, numerous studies have been conducted of late that indicate that these planets may not have the necessary conditions to support life. The latest comes from Harvard University, where postdoctoral researcher Manasvi Lingam and Professor Abraham Loeb demonstrate that planets around M-type stars may not get enough radiation from their stars for photosynthesis to occur.

Continue reading “Habitable Planets Around Red Dwarf Stars Might not get Enough Photons to Support Plant Life”