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.
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.
Despite all we know about the formation and evolution of the Universe, the very early days are still kind of mysterious. With our knowledge of physics we can shed some light on the nature of the earliest stars, even though they’re almost certainly long gone.
Now a new discovery is confirming what scientists think they know about the early Universe, by shedding light on a star that’s still shining.
For the first time ever, astronomers have witnessed a coronal mass ejection (CME) on a star other than our very own Sun. The star, named HR 9024 (and also known as OU Andromeda,) is about 455 light years away, in the constellation Andromeda. It’s an active, variable star with a strong magnetic field, which astronomers say may cause CMEs.
A rogue star is one that has escaped the gravitational pull of its home galaxy. These stars drift through intergalactic space, and so are sometimes called intergalactic stars. Sometimes, when a rogue star is ejected from its galaxy, it drags its binary pair along for the ride.
Stars live and die on epic time scales. Tens of millions of years, hundreds of millions of years, even billions of years or longer. Maybe the only thing that surpasses that epicness is when two dead stars join together and come back to life.
A planetary nebula is one of the most beautiful objects in the universe. Formed from the decaying remnants of a mid-sized star like a sun, no two are alike. Cosmically ephemeral, they last for only about 10,000 years – a blink of a cosmic eye. And yet they are vitally important, as their processed elements spread and intermingle with the interstellar medium in preparation for forming a new generation of stars. So studying them is important for understanding stellar evolution. But unlike their stellar brethren, since no two are alike, it’s hard to efficiently pick them out of astronomical deep-sky surveys. Thankfully, a research team has recently developed a method for doing just that, and their work could open up the door to fully understanding the great circle of stellar life.
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.
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.
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.