Two thousand five hundred years ago, during the height of the bronze age, an old red star died. Its outer layers expanded over time, becoming what is now known as the Southern Ring Nebula, or less romantically, NGC 3132. By the looks of it, this planetary nebula looks like many others. As Sun-like stars die, they swell to become red giants before becoming a white dwarf, and their outer layers typically become a planetary nebula. But a recent study finds that this particular nebula formed in a way quite messier than we had thought.Continue reading “The Formation of the Southern Ring Nebula was Messier Than the Death of a Single Star”
Astronomical images never cease to delight, and the European Southern Observatory’s image of the Vela nebula is no exception.Continue reading “ESO Finds the Ghostly Image of a Dying Star”
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The Stingray Nebula is the youngest known planetary nebula. For half a century astronomers have witnessed its formation, and now they’ve noticed something strange: it’s fading away.Continue reading “20 Years of Hubble Photos Show how the Stingray Nebula is Fading”
Planetary nebulae are astronomy’s gateway drug. Their eye-catching forms make us wonder what process created them, and what else is going on up there in the night sky. They’re some of the most beautiful, ephemeral looking objects in all of nature.
The Hubble Space Telescope is responsible for many of our most gorgeous images of planetary nebulae. But the images are more than just engrossing eye candy. They’re documentation of a complex process that plays out over tens of thousands of years, all across the Universe.
And they’re a death knell for the star that dwells within.Continue reading “New Hubble Photos of Planetary Nebulae”
According to the most widely accepted theory of planet formation (the Nebular Hypothesis), the Solar System began roughly 4.6 billion years ago from a massive cloud of dust and gas (aka. a nebula). After the cloud experienced gravitational collapse at the center, forming the Sun, the remaining gas and dust fell into a disk that orbited it. The planets gradually accreted from this disk over time, creating the system we know today.
However, until now, scientists have wondered how dust could come together in microgravity to form everything from stars and planets to asteroids. However, a new study by a team of German researchers (and co-authored by Rutgers University) found that matter in microgravity spontaneously develops strong electrical charges and stick together. These findings could resolve the long mystery of how planets formed.Continue reading “Planets Started Out From Dust Clumping Together. Here’s How”
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.Continue reading “This Star Has Reached the End of its 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.Continue reading “Can You Spot a Planetary Nebula from a Few Blurry Pixels? Astronomers Can – Here’s How”
Welcome back to Messier Monday! Today, we continue in our tribute to our dear friend, Tammy Plotner, by looking at the “little dumbbell” itself, the planetary nebula known as Messier 76!
During the 18th century, famed French astronomer Charles Messier noticed the presence of several “nebulous objects” while surveying the night sky. Originally mistaking these objects for comets, he began to catalog them so that others would not make the same mistake. Today, the resulting list (known as the Messier Catalog) includes over 100 objects and is one of the most influential catalogs of Deep Space Objects.
One of these objects is the Messier 76 (aka. the Little Dumbbell Nebula, the Barbell Nebula, or the Cork Nebula) a planetary nebula located about 2,500 light years away in the Perseus Constellation. While it is easy to find because of its proximity to the Cassiopeia Constellation (located just south of it), the faintness of this nebula makes it one of the more difficult Messier Objects to observe. Continue reading “Messier 76 – the NGC 650/651 Planetary Nebula”
Planetary nebulae are a fascinating astronomical phenomena, even if the name is a bit misleading. Rather than being associated with planets, these glowing shells of gas and dust are formed when stars enter the final phases of their lifespan and throw off their outer layers. In many cases, this process and the subsequent structure of the nebula is the result of the star interacting with a nearby companion star.
Recently, while examining the planetary nebula M3-1, an international team of astronomers noted something rather interesting. After observing the nebula’s central star, which is actually a binary system, they noticed that the pair had an incredibly short orbital period – i.e. the stars orbit each other once every 3 hours and 5 minutes. Based on this behavior, the pair are likely to merge and trigger a nova explosion.
The life cycle of our Sun began roughly 4.6 billion years ago. In roughly 4.5 to 5.5 billion years, when it depletes its supply of hydrogen and helium, it will enter into its Red Giant Branch (RGB) phase, where it will expand to several times its current size and maybe even consume Earth! And then, when it has reached the end of its life-cycle, it is believed that it will blow off its outer layers and become a white dwarf.
Until recently, astronomers were not certain how this would take place and whether or not our Sun would end up as a planetary nebula (as most other stars in our Universe do). But thanks to a new study by an international team of astronomers, it is now understood that our Sun will end its life-cycle by turning into a massive ring of luminous interstellar gas and dust – known as a planetary nebula.
Their study, titled “The mysterious age invariance of the cut-off the Planetary Nebula Luminosity Function“, was recently published in the scientific journal Nature. The study was led by Krzysztof Gesicki, an astrophysicist from Nicolaus Copernicus University, Poland; and included Albert Zijlstra and M Miller Bertolami – a professor from the University of Manchester and an astronomer the Instituto de Astrofísica de La Plata (IALP), Argentina, respectively.
Roughly 90% of all stars end up as a planetary nebula, which traces the transition they go through between being a red giant and a white dwarf. However, scientists were previously unsure if our Sun would follow this same path, as it was thought to not be massive enough to create a visible planetary nebula. To determine if this would be the case, the team developed a new stellar, data-model that predicts the lifecycle of stars.
This model – which they refer to as the Planetary Nebula Luminosity Function (PNLF) -was used to predict the brightness of the ejected envelope for stars of different masses and ages. What they found was that our Sun was just massive enough to end up as a faint nebula. As Prof. Zijlstra explained in a Manchester University press release:
“When a star dies it ejects a mass of gas and dust – known as its envelope – into space. The envelope can be as much as half the star’s mass. This reveals the star’s core, which by this point in the star’s life is running out of fuel, eventually turning off and before finally dying. It is only then the hot core makes the ejected envelope shine brightly for around 10,000 years – a brief period in astronomy. This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light years, where the star itself would have been much too faint to see.”
This model also addressed an enduring mystery in astronomy, which is why the brightest nebulae in distant galaxies all appear to have the same luminosity. Roughly 25 years ago, astronomers began to observe this, and found that they could gauge the distance to other galaxies (in theory) by examining their brightest planetary nebulae. However, the model created by Gesicki and his colleagues contradicted this theory.
In short, the luminosity of a planetary nebula does not come down to the mass of the star creating it, as was previously assumed. “Old, low mass stars should make much fainter planetary nebulae than young, more massive stars,” said Prof. Zijlstra. “This has become a source of conflict for the past for 25 years. The data said you could get bright planetary nebulae from low mass stars like the Sun, the models said that was not possible, anything less than about twice the mass of the sun would give a planetary nebula too faint to see.”
Essentially, the new models demonstrated that after a star ejects its envelope, it will heat up three times faster than what older models indicated – which makes it much easier for low mass stars to form a bright planetary nebula. The new models also indicated that the Sun is almost exactly at the lower cut off for low mass stars that will still produce a visible, though faint, planetary nebula. Anything smaller, Prof. Zijlstra added, will not produce a nebula:
“We found that stars with mass less than 1.1 times the mass of the sun produce fainter nebula, and stars more massive than 3 solar masses brighter nebulae, but for the rest the predicted brightness is very close to what had been observed. Problem solved, after 25 years!”
In the end, this study and the model the team produced has some truly beneficial implications for astronomers. Not only have they indicated with scientific confidence what will happen to our Sun when it dies (for the first time), they have also provided a powerful diagnostic tool for determining the history of star formation for intermediate-age stars (a few billion years old) in distant galaxies.
It’s also good to know that when our Sun does reach the end of lifespan, billions of years from now, whatever progeny we leave behind will be able to appreciate it – even if they are looking across the vast distances of space.