Tag Archives: Stellar astronomy

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Astronomers Find Rare Star System That Will Trigger a Kilonova

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An artist’s rendition of the binary stay system, called CPD-29 2176.
Illustration: Noir Lab

The universe has no shortage of oddities, and researchers at the National Science Foundation’s NOIRLab have observed another one in the form of a particular binary star system. The system, called CPD-29 2176, will eventually trigger a kilonova, a celestial event in which two neutron stars collide in a massive explosion that forms heavy elements, including gold and platinum.

CPD-29 2176 is located around 11,400 light-years from Earth and was found by researchers using NASA’s Neil Gehrels Swift Observatory. Astronomers then conducted more observations at NOIRLab’s Cerro Tololo Inter-American Observatory in Chile. CPD-29 2176 is home to one neutron star and one massive star that is in the process of going supernova, only to become a second neutron star in the future. Eventually, the two neutron stars will collide, producing a kilonova, an explosion that is thought to produce bursts of gamma rays and large amounts of gold and platinum. The paper documenting the research team’s find is published today in Nature.

“We know that the Milky Way contains at least 100 billion stars and likely hundreds of billions more. This remarkable binary system is essentially a one-in-ten-billion system,” said André-Nicolas Chené in a NOIRLab press release. Chené is a NOIRLab astronomer and an author on the study. “Prior to our study, the estimate was that only one or two such systems should exist in a spiral galaxy like the Milky Way.”

While many stars implode was a powerful supernova when they die, the dying star in CPD-29 2176 is becoming an ultra-stripped supernova. An ultra-stripped supernova lacks the vast amount of force that a typical supernova has, since the dying star has had much of its mass stripped by its companion. The researchers think that the neutron star in the system was also formed with an ultra-stripped supernova and argue that this is the reason that CPD-29 2176 is able to remain as a binary—a typical supernova would have enough power to kick a companion star out of its orbit.

“The current neutron star would have to form without ejecting its companion from the system. An ultra-stripped supernova is the best explanation for why these companion stars are in such a tight orbit,” said lead author Noel D. Richardson, a physics and astronomy professor at Embry-Riddle Aeronautical University, in the NOIRLab release. “To one day create a kilonova, the other star would also need to explode as an ultra-stripped supernova so the two neutron stars could eventually collide and merge.”

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It will take around one million years for the star undergoing ultra-stripped supernova to turn into a neutron star. It is then when the two stars will begin to spiral into each other, eventually resulting in the metal-producing kilonova, according to the research. In these dramatic cosmic endings, we can look forward to the creation of the same elements that make life possible.  

More: Watch Four Planets Spin Around a Star 130 Million Light-Years Away

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Your Ancestors Might Have Seen Red Star Betelgeuse as Yellow

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New research into the star Betelgeuse indicates that the red giant, easily seen in the constellation Orion, may have appeared more orange-yellow in the not-so-distant past.

The research is based on historical sources that described the color of stars in the sky. A recent team looked at 236 stars bright enough that their colors can be seen with the naked eye and sifted through historical records describing the stars, written by the likes of Ptolemy and Tycho Brahe.

Betelgeuse is one of the brightest stars in the sky, located around 600 light-years from Earth in the constellation Orion. Betelgeuse is a red supergiant, with a relatively cool surface temperature and clocking in at about 764 times as large as the Sun. If Betelgeuse were located at the center of our solar system, the four terrestrial planets and Jupiter would be beneath its surface.

The team found that the recorded color of Betelgeuse (we’re allowed to write that more than three times) has changed over the last couple of millennia. Their research is published in the Monthly Notices of the Royal Astronomical Society.

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“There are quite a number of astrophysical problems which can hardly be solved without historical observations,” said Ralph Neuhäuser, an astrophysicist at the University of Jena and lead author of the recent paper, in a university release.

In the work, the team cataloged the descriptions of Betelgeuse by notable astronomers over the last 2,000 years, including Sima Qian in the 2nd century BCE in China, Hyginus and Germanicus in the first century CE in Europe, and Al-Ṣūfī in the 10th century CE in Persia.

The more qualitative reports—for example, Sima Qian stated that Betelgeuse’s color was between the redness of Antares and the blueness of Bellatrix, another star in Orion—allowed the team to approximate Betelgeuse’s color at specific points in time.

“The very fact that it changed in color within two millennia from yellow-orange to red tells us, together with theoretical calculations, that it has 14 times the mass of our Sun – and the mass is the main parameter defining the evolution of stars,” Neuhäuser said.

Betelgeuse is going through some remarkable changes at present. A few years ago, the giant, brilliant star began dimming. At its peak, the star was 40% fainter than normal. Now, astrophysicists believe Betelgeuse had the star’s equivalent of an odious burp, one that created a cloud that partially obscured the star from our view.

Betelgeuse is near the end of its life, and no one knows exactly when it will explode in a dazzling supernova. We’re surely in for more technicolor surprises from this familiar giant star.

More: The Mystery of Betelgeuse’s Weird Dimming Is Likely Solved

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This Massive Planet Shouldn’t Exist

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Conceptual image of the newly discovered exoplanet, with its two host stars in the background.
Illustration: ESO/L. Calçada

Scientists have spotted an unusually large exoplanet in orbit around b Centauri, a massive two-star system that is visible to the unaided eye. With a combined weight of roughly 10 Suns, it’s now the heaviest star system known to host a planet.

Let’s get right to the nitty-gritty of this discovery, the details of which were published today in Nature. The newly discovered planet, called “b Cen (AB)b,” is likely a gas giant and is heavier than 10 Jupiters combined, making it one of the most massive planets ever discovered. It orbits the b Centauri binary system, which is located 325 light-years from Earth and has a combined mass of nearly 10 Suns. At 52 billion miles from its host stars, this planet has one of the widest orbits ever detected. By comparison, Pluto orbits the Sun at around 3.3 billion miles, so yeah, that’s an unbelievable separation.

Until now, planets had not been found in orbit around star systems weighing more than three solar masses. Astronomers didn’t think planets could form around systems like this, so it’s forcing a major rethink of what’s possible in terms of planetary architectures and the conditions under which planets can form. Markus Janson, an astronomer at Stockholm University and the first author of the study, said the thing that excites him most about this discovery is the “astounding diversity” of exoplanetary systems.

“It seems that no matter where we look—around small or big stars, single stars or binary stars, alive stars or dead stellar remnants—we always find planets in some form, even in places we didn’t think possible,” he wrote in an email.

That a planet exists in this star system is indeed surprising. Young stars have protoplanetary disks around them, from which planets eventually emerge. A hot star system like b Centauri, however, is not supposed to be conducive to planetary formation, owing to tremendous amounts of ultraviolet and X-ray radiation. This high-energy radiation “tends to destroy the disks in a very short time,” and it was “thought that this wouldn’t give planets enough time to form in the disk before it disappeared,” Janson said. Yet there it is—a full fledged planet around the b Centauri system.

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Janson and his colleagues spotted b Cen (AB)b with the SPHERE exoplanet imager at the European Southern Observatory’s Very Large Telescope in Chile, on March 20, 2019 and then again on April 10, 2021. The astronomers used a high-contrast imaging technique to detect the planet, in which they distinguished the faint light coming from the planet from the very bright light coming from the star system itself.

A deformable mirror on SPHERE that can rapidly change shape counteracted blurring effects caused by Earth’s atmosphere, while a chronograph blocked excessive light coming in from the source target. A special technique, known as Angular Differential Imaging, ruled out extraneous optical effects. Interestingly, follow-up work showed that the planet was observed 20 years ago by a different ESO instrument, but it wasn’t properly identified at the time.

A neat observation is how the ratio between the masses of the star system and its planet closely matches that of our Sun and Jupiter. But that’s where the comparison ends, as the scale of b Centauri is far vaster, as the planet is 10 times the mass of Jupiter and with an orbit that’s 100 times wider.

I asked Janson if b Cen (AB)b might actually be a brown dwarf (a so-called failed star), or if it qualifies as a new kind of planet altogether. Brown dwarfs “would be hotter than what we observe, so we can exclude that option,” he replied, but a “new class of planets is a possibility,” he added, saying astronomers “would have to study a larger sample of similar systems before we can say something conclusive about that.”

The team is currently running a survey called BEAST, which is scanning 85 stars with characteristics similar to b Centauri. BEAST could show us how common these sorts of planets might be, while also shedding light on how they might form.

“The discovery of the planet in the b Centauri system and any other future results from BEAST will provide input for planet formation theorists to refine their theories, and hopefully find the physics that allow for the wide range of planets that are observed, both around massive stars and simultaneously around more Sun-like and smaller stars,” Janson said.

From an astrobiological perspective, Janson said b Centauri is “possibly one of the worst places in the galaxy to host life.” Together, the binary pair spew enormous amounts of UV and X-ray radiation, “which would sterilize any surface that is exposed to it,” so “life on any surface in the system is certainly not very likely.” Still, Janson did not rule out the possibility that life could exist in subterranean oceans, matching ongoing speculation about basic life existing on Jupiter’s moon Europa or Saturn’s moon Enceladus.

Ultimately, the new discovery “provides us with a new important piece of the puzzle as to how planets form, which is an understanding that we need to have if we are to understand where we come from and how we fit into the universe at large,” Janson said.

More: Two Failed Stars in Our Cosmic Neighborhood Seem to Have… Stripes?

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The Search for Life Around Alpha Centauri Just Took a Major Leap Forward

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Optical and X-ray images of the Alpha Centauri system.
Image: NASA

Our nearest neighbor, Alpha Centauri, is 4.37 light-years from Earth, which is super close from a cosmological perspective but achingly far from a human point of view. A new telescope promises to bring this intriguing star system, and any habitable planets it holds, into closer view.

The new mission, called TOLIMAN, was announced today in a press release. TOLIMAN is the ancient Arabic name for Alpha Centauri—the closest star system to Earth—but it’s also an acronym for Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighbourhood. Once in space, astronomers will use the orbital observatory to search for potentially habitable exoplanets around Alpha Centauri.

The international collaboration includes teams from the University of Sydney, Breakthrough Initiatives, Saber Astronautics, and NASA’s Jet Propulsion Laboratory. Peter Tuthill from the Sydney Institute for Astronomy at the University of Sydney will lead the project.

Alpha Centauri A (left) and Alpha Centauri B as viewed by the Hubble Space Telescope.
Image: NASA/ESA

We’re quite fortunate to have such an intriguing next-door neighbor. Alpha Centauri is a triple star system consisting of two Sun-like stars, named Alpha Centauri A and Alpha Centauri B, and a red dwarf known as Proxima Centauri.

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Two exoplanets are known to orbit Proxima Centauri: an Earth-sized planet parked inside the habitable zone (i.e. that sweet spot within which liquid water is stable at the surface) and a super-Earth located farther out. Alpha Centauri A is suspected to host a Neptune-sized exoplanet, but astronomers aren’t entirely certain. An exoplanet has yet to be discovered in orbit around Alpha Centauri B. Other exoplanets are likely still awaiting detection—and that’s where TOLIMAN comes in.

Proposed design of the TOLMAN telescope.
Image: University of Sydney/Peter Tuthill

“Our nearest stellar neighbours—the Alpha Centauri and Proxima Centauri systems—are turning out to be extraordinarily interesting,” Pete Worden, executive director of Breakthrough Initiatives, said in the press release. “The TOLIMAN mission will be a huge step towards finding out if planets capable of supporting life exist there.”

Breakthrough Initiatives, founded by billionaire Yuri Milner, provided seed funding for the project, as did the Australian government through its International Space Investment Expand Capability Grants program. Saber Astronautics, the recipient of AUD$788,00 (USD$573,300) from the Australian government, will provide spaceflight mission operations support, including space traffic management and satellite communications. The firm has facilities in both Australia and the United States.

Simulated view of the Alpha Centauri binary system as it’s expected to appear through the diffractive pupil lens.
Image: Peter Tuthill

Jason Held, CEO of Saber Astronautics, described TOLIMAN in the press release as “an exciting, bleeding-edge space telescope,” one that will be “supplied by an exceptional international collaboration.” To which he added: “It will be a joy to fly this bird.”

TOLIMAN will be custom-tailored for the mission, and its strong suit will be in making extremely fine measurements of the positions of the stars. A key feature of the new telescope is a “diffractive pupil lens.” By dispersing stellar light into flower-like patterns, the lens will make it easier for astronomers to spot wobbles caused by orbiting exoplanets. Once an exoplanet is detected, more specialized telescopes can be recruited to search for potential biosignatures in the atmosphere or surface. The telescope is expected to reach orbit in 2023, as Centauri Dreams reports.

In 2019, scientists with Breakthrough Listen, one of several projects supported by Breakthrough Initiatives, identified a candidate signal coming from Proxima Centauri, in what was the first and so far only potential alien technosignature detected by the group. Subsequent research found the signal to be of human origin, ruling out an alien civilization as the source.

More: What to know about Kessler Syndrome, the ultimate space disaster.

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Exploding Star Seen in Real Time

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Big-badda-boom: Supernova SN 2020fqv.
Image: NASA, ESA, Ryan Foley (UC Santa Cruz), Joseph DePasquale (STScI)

A star located 60 million light years away went supernova last year, and astronomers managed to capture all stages of the stellar explosion using telescopes both on the ground and in space.

The doomed star has been known to astronomers for quite some time, but in April 2020, it suddenly went supernova, earning it the designation SN 2020fqv. The Zwicky Transient Facility at the Palomar Observatory in San Diego, California, happened to be watching, as was NASA’s Transiting Exoplanet Survey Satellite (TESS), which is normally used to detect distant exoplanets. Alerted to the rare event, astronomers then scrambled to get the Hubble Space Telescope involved, among several other ground-based telescopes.

This awesome display of astronomical power has yielded a dataset of unprecedented proportions, with independent observations gathered before, during, and after the explosion. It’s providing a rare multifaceted view of a supernova during its earliest phase of destruction. The resulting data should vastly improve our understanding of the processes involved when stars go supernova, and possibly lead to an early warning system in which astronomers can predict the timing of such events.

The location of SN 2020fqv within its host galaxy.
Image: NASA, ESA, Ryan Foley (UC Santa Cruz), Joseph DePasquale (STScI)

“We used to talk about supernova work like we were crime scene investigators, where we would show up after the fact and try to figure out what happened to that star,” Ryan Foley, an astronomer at the University of California, Santa Cruz, and the leader of the investigation, explained in a press release. “This is a different situation, because we really know what’s going on and we actually see the death in real time.”

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Of course, it took 60 million years for the light from this supernova to reach Earth, so it’s not exactly happening in “real time,” but you get what Foley is saying. SN 2020fqv is located in the Butterfly Galaxies—a pair of interacting galaxies—and it can be spotted in the Virgo constellation.

Observations of circumstellar material in close proximity to the star were made by Hubble just hours after the explosion, which, wow. The star shed this material during the past year, offering a unique perspective of the various stages that occur just prior to a supernova explosion.

“We rarely get to examine this very close-in circumstellar material since it is only visible for a very short time, and we usually don’t start observing a supernova until at least a few days after the explosion,” said Samaporn Tinyanont, the lead author of the paper, which is set for publication in the Monthly Notices of the Royal Astronomical Society.

That stars become more active prior to an explosion is known, Betelgeuse being a good example. This red giant star has been belching out a lot of material lately, and while it may not go supernova any time soon, it’s clearly exhibiting the tell-tale signs of its imminent destruction.

TESS managed to capture one image of the evolving system every 30 minutes, starting a few days before the explosion and ending several weeks afterward. Hubble joined in on the action a few hours after the explosion was first detected. Archival data dating back to the 1990s was also brought in for the analysis, resulting in an unprecedented multi-decade survey of a star on its way out.

Among the new results is an accurate weighing of the doomed star, which the team did by using multiple astronomical methods. At the time of the explosion, the star was 14 to 15 times the mass of our Sun—a critical piece of insight that will help astronomers to understand the physical conditions in place as a star enters into its death throes.

In the press release, the researchers referred to SN 2020fqv as the “Rosetta Stone of supernovas,” as the new observations could translate hidden or poorly understood signals into meaningful data.

“This could be a warning system,” said Foley. “So if you see a star start to shake around a bit, start acting up, then maybe we should pay more attention and really try to understand what’s going on there before it explodes.” To which he added: “As we find more and more of these supernovas with this sort of excellent data set, we’ll be able to understand better what’s happening in the last few years of a star’s life.”

More: A vanished supernova will reappear in 16 years.

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Astronomers Find Massive Space ‘Cavity’ Possibly Left Behind by Explosion

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Astronomers measuring the shapes and sizes of two gas clouds in space have discovered a big gap between them, leading them to believe that the clouds are what’s left of a series of stellar explosions or a single massive one.

The cavity in space is 500 light-years across and sits between the constellations Perseus and Taurus, which both host giant gas clouds called molecular clouds. Researchers studying the empty space believe one of two things may have happened: Either a single, massive supernova blasted all the gassy material outward, or several supernovae created the two clouds, with tons of space between them.

Supernovae are expected to push gas outward from the site of their explosion, which causes all that gas to form a shell-like geometry. In this case, the two cloud structures on either side of the space became Perseus and Taurus. Together, they form the “Per-Tau Shell.” The team’s research is published today in two papers in the Astrophysical Journal Letters.

“One may still expect to see remnants of the stellar cluster, in which the supernova(e) went off,” said co-author Shmuel Bialy, a theoretical astrophysicist at the Center for Astrophysics | Harvard and Smithsonian, in an email to Gizmodo. “We see some preliminary evidence for such a stellar cluster in the center, however this requires further analysis, and this is something we plan to dive into in the future.”

The Perseus and Taurus gas clouds are stellar nurseries in the Milky Way, meaning they give birth to new stars. The team actually discovered the cavity between the clouds after rendering the objects in 3D, the first time this sort of approach has been done, to see their structure as never before. Perseus and Taurus are just two of a dozen clouds whose structures the team have now mapped in 3D.

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“We’ve been able to see these clouds for decades, but we never knew their true shape, depth or thickness. We also were unsure how far away the clouds were,” said lead author Catherine Zucker, a postdoctoral researcher at the Center for Astrophysics | Harvard and Smithsonian, in a press release. “Now we know where they lie with only 1 percent uncertainty, allowing us to discern this void between them.”

The cavity is perhaps most visible in an interactive model that allows you to drag and resize the molecular clouds and the space between them. The team will probe the center of that space to find evidence of the supernova (or novae)’s origin, like arson investigators looking for a snuffed-out match. The 3D model can also be visualized in augmented reality using a QR code in the paper.

You can basically think of the Per-Tau shell as a nebula: the typically dazzling shapes of gas clouds that emerge in the aftermath of a star’s death. But in this case, the gas clouds didn’t appear in the blast’s immediate aftermath, and the Per-Tau shell doesn’t emit high-energy X-rays like nebulae do.

“We think the Per-Tau shell we see is a direct result of the supernova, only that we observe it at a much later stage (after some 10-20 million years), and thus the shell has already expanded to a much larger size (+ there may be the possibility that there were more supernovae occurring in the meantime, further helping the shell expansion),” Bialy wrote.

Going forward, the team hopes to figure out whether these cavities between gas clouds in the aftermath of supernovae are the rule or the exception for star formation. The emergence of new stars from the far-flung remains of old ones shows how the universe continues to reshape itself, gases to gases and dust to dust.

More: Astronomers Think They’ve Spotted a Rare Kind of Supernova Only Predicted to Exist

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This Blasted Star Is Getting the Hell Out of the Milky Way

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Careening through the Milky Way at nearly 2 million miles per hour, the star LP 40–365 shows no signs of stopping. A team of astronomers recently figured out that the star was propelled into its current speedrun by a supernova explosion millions of years ago.

LP 40–365 is unusual. It’s a white dwarf, a small, compact star at the end of its life, and it’s very rich in metals. LP 40–365 also has own atmosphere, which is mostly composed of oxygen and neon. But most important to this story is that the star is a runaway from a huge stellar explosion, which set in motion its dash out of the galaxy.

When a white dwarf is orbiting another (in what’s called a white dwarf binary), one star gives up mass to the other, which gobbles it up steadily. The binaries can also emit gravitational waves—perturbations in spacetime—as they orbit one another, with the hungry star (the accretor) in the duo detonating in a huge thermonuclear explosion.

The team behind the new research isn’t sure whether stars like LP 40–365 are typically the donors or the accretors in their white dwarf binary systems, but they believe this particular hot metal ball is basically stellar shrapnel from the accreting star, which eventually exploded in fantastic fashion. Their findings were published this week in The Astrophysical Journal Letters.

“To have gone through partial detonation and still survive is very cool and unique, and it’s only in the last few years that we’ve started to think this kind of star could exist,” Odelia Putterman, a researcher now at Occidental College and a co-author of the paper, told The Brink, a publication of Boston University.

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The team found the star using observations from the Transiting Exoplanet Survey Satellite (TESS) and the Hubble Space Telescope, which turned up a fast-moving object with a regular pattern of dimming and brightening. That suggested the star was slowly rotating—completing its rotation every nine hours—as it hurtled through space. That’s a pretty slow rotation rate, and weird to think about in conjunction with how fast the star is moving through space. It’s from that rotation rate that the team figures the white dwarf is the remnant of one star in a binary system collapsing in on itself, blasting its partner and all else in the area outwards at extraordinary speed. Based on the team’s calculations, they believe LP 40–365 has been traveling from its origin galaxy for a little over 5 million years.

“The star is basically being slingshotted from the explosion, and we’re [observing] its rotation on its way out,” Putterman told The Brink .

More: Astronomers Think They’ve Spotted a Rare Kind of Supernova Only Predicted to Exist

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Astronomers Found a White Dwarf Star the Size of Our Moon

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An artist’s depiction of the white dwarf, left, in comparison with our Moon, right.
Illustration: Giuseppe Parisi

Imagine a white-hot, dying star that contains more mass than our Sun packed into an orb just a little larger than our Moon. That’s ZTF J190132.9+145808.7, a record-setting white dwarf recently identified by astronomers.

The star was seen from the Zwicky Transient Facility, which operates out of California and Hawaii, hence the first letters in the object’s unwieldy name. Based on the object’s extreme magnetic field and mass—nearly a billion times as strong as the Sun and 1.35 times its mass—the researchers believe it is the result of a white dwarf merger. Their results were published this week in Nature.

White dwarfs (also called degenerate dwarfs) are the end stage of many small and medium-sized stars. When white dwarfs orbiting each other (in what’s called a binary star system) eventually merge, they can explode in a supernova. But if they aren’t that massive, they just form one bigger white dwarf. “We caught this very interesting object that wasn’t quite massive enough to explode,” said Ilaria Caiazzo, an astrophysicist at the California Institute of Technology and lead author of the paper, in a Keck Observatory press release. “We are truly probing how massive a white dwarf can be.”

ZTF J190132.9+145808.7 also has a very fast rotation, performing a full revolution in just under seven minutes. Its diameter is about 2,670 miles, slightly more petite the previously known smallest white dwarfs, which both had diameters of about 3,100 miles. Studying the strength of the star’s magnetic field in conjunction with its fast rotation led the research team to the conclusion that the dwarf was once two separate stars that came together in a dense, fast-spinning collab.

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The team believes that ZTF J190132.9+145808.7 has a chance of turning into a neutron star, one possible end-stage of stellar life in which a star will end up collapsing in on itself. “It is so massive and dense that, in its core, electrons are being captured by protons in nuclei to form neutrons,” Caiazzo said in the same release. “Because the pressure from electrons pushes against the force of gravity, keeping the star intact, the core collapses when a large enough number of electrons are removed.”

Plenty of known unknowns abound, such as how strong magnetic fields arise from white dwarf mergers and the prevalence of such mergers among white dwarfs in space. The telescopes keep looking skywards, so as long as the dwarfs remain large enough to be seen, it’s safe to say there will be more record-breakers in the future.

More: Astronomers Discover First Known Planet to Orbit a White Dwarf Star

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Amateur Astronomer Spots a Rare Visible Nova

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Left: The horizontal white line points to the new nova. Right: The same region of space seen four days earlier, sans nova.
Image: Yuji Nakamura/NAOJ

A new nova, appearing in the northern constellation of Cassiopeia, can be seen with binoculars and small telescopes, but this transient object won’t stick around for long. Here’s how you can spot Nova V1405 Cas before it’s too late.

Amateur astronomer Yuji Nakamura from Kameyama City of Japan spotted the nova on March 18 at 7:10 p.m. local time and promptly reported his discovery to the National Astronomical Observatory of Japan (NAOJ). Astronomers using Kyoto University’s Seimei Telescope in Okayama Prefecture confirmed the nova at 4:40 a.m. the following day.

“This observation was carried out only half a day after the discovery, demonstrating fruitful collaboration between amateur astronomers and researchers,” announced the NAOJ in a statement. “Since we cannot predict when and in what direction novae will occur, discoveries by amateur astronomers contribute significantly to our understanding of the phenomena.”

Designated Nova V1405 Cas, the object was initially detected at 9.6 magnitude (too faint to be seen with the unaided eye), but it brightened significantly in the days following its discovery. As EarthSky reports, the nova is now glowing at around 7.6 magnitude, making it visible to binoculars and small telescopes and quite possibly the unaided eye (humans can spot celestial objects beginning at around 6.5 magnitude, but people might actually be able to spot the nova without equipment if the conditions are just right).

Cassiopeia constellation.
Image: Korrigan/Orthogaffe (Fair Use)

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And yes, you should make the effort to see it if you can. Novae of this type, in which nuclear explosions cause the spectacular brightening of white dwarf stars, are common in the Milky Way, but visible novae are relatively rare. One of the last naked-eye novae, V1369 Cen, happened in 2013, and it was only visible in the southern hemisphere. Nova V1405 Cas is a transient object, and it will fade during the next several weeks and months.

EarthSky provides detailed information on how you can best spot V1405 Cas, but very simply, you should first locate the constellation Cassiopeia, which can be seen above the horizon when looking north-northwest after the Sun goes down (use a phone app like Sky Guide to help you locate celestial objects). Then, using the bottom two stars in Cassiopeia, draw a line to the right “for approximately the same distance as the two stars are apart from each other and start looking for a little star cluster known as M52,” EarthSky recommends. From here you should be able to spot the nova, which obviously won’t appear on star maps. Sky & Telescope recommends nightfall or just before dawn as the best times to view the new nova.

V1405 Cas is not to be confused with a Type Ia supernova, as it’s not a star that has outright exploded. This is a classic nova, involving a white dwarf and a main sequence star caught in a tight mutual orbit. The small, dense white dwarf pulls hydrogen away from its companion, and this hydrogen gets increasingly compact and hot. Eventually, nuclear fusion is triggered, causing the white dwarf to glow 50,000 to 100,000 times brighter than normal. The white dwarf survives these surface explosions, and the process begins anew.

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