StarDate

Vulpecula, the fox, doesn’t have a lot of impressive stars. But it sure has a lot of impressive dead ones. That’s where astronomers discovered the first neutron star — which also happened to be the first pulsar. And a few years ago, it’s where they discovered the first fast radio burst in our home galaxy — an object that’s also a neutron star.

A neutron star is the corpse of a massive star that exploded as a supernova. The star’s core collapsed to just a few miles across, but it’s more massive than the Sun.

The first neutron star was discovered in Vulpecula in 1967. It was emitting regular “pulses” of radio waves as it spun on its axis. So it was called a pulsar. Some pulsars steal gas from normal companion stars, which makes them spin up to hundreds of times per second. The first of those was discovered in Vulpecula as well.

And in 2020, another neutron star there suddenly produced short bursts of radio waves that didn’t sync up with how fast it spins — the first sighting of such an event in the Milky Way.

A recent study says it was a result of an outburst of charged particles. The star generates an extremely powerful magnetic field. A disruption in the field likely generated the “volcano” of particles. That slowed the star’s rotation by a tiny bit, producing the radio bursts — and another interesting “dead” star in Vulpecula.

The fox is in the northeast at first light, to the right of Cygnus, the swan.
 

Script by Damond Benningfield

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Vulpecula, the fox, is a faint constellation. Unless you live away from city lights, you might not see any of its stars.

But that may not always be the case. It’s giving birth to some monster stars. When the “cocoon” around them clears away, some of the stars should be easy targets. And even before then, some of them will explode and briefly shine through the haze. Of course, you’ll have to wait a bit — it’ll take millions of years to play out.

The “monster” stars are part of the Vulpecula OB1 association. It’s a vast complex of stars, plus gas and dust that are forming more stars.

The association is named for its abundance of “O” and “B” stars. They’re the biggest, heaviest, and brightest of all stars. They can be dozens of times the mass of the Sun, and hundreds of thousands of times brighter.

We can’t see any of them with our eyes alone, though. The complex is about 8,000 light-years away, and the stars are still enveloped by gas and dust. Over time, that material will either collapse to form more stars, or it’ll be blown away. That will expose the stars to view.

Many of the stars will explode as supernovas. They’ll leave behind tiny, dense corpses — neutron stars or black holes. In fact, some stars in Vulpecula already have, and we’ll talk about them tomorrow.

The fox is in the northeast at dawn, to the right of bright Cygnus, the swan. But you need dark skies to see any of the fox’s stars — at least for now.
 

Script by Damond Benningfield

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Our home galaxy, the Milky Way, is a vast collection of hundreds of billions of stars. And the population is growing. On average, the galaxy adds a few new stars every year.

Across the universe, though, the rate of star formation has slowed down by a good bit since the first era of starbirth. And it will continue to slow in the coming eons as the raw materials for making stars are used up.

Stars are born from giant clouds of hydrogen and other elements. Nuclear reactions in the cores of the stars “fuse” the hydrogen atoms to make helium, which in turn is fused to make even heavier elements. This process uses up the hydrogen. In fact, it’s dropped from about 75 percent of the total mass of the universe just after the Big Bang, to about 73 percent today.

That still leaves a lot of hydrogen. But it’s much harder to gather it up to make new stars. Much of it is already locked up in stars, so there’s not as much available for the big gas clouds that give birth to stars. In fact, some galaxies have already used up almost all of their supplies.

There’s still enough in gas-rich galaxies like the Milky Way to keep making stars for many, many billions of years. Eventually, though, almost all of the hydrogen will be incorporated into stars. And the little free hydrogen that remains will be so widely spread that there won’t be enough to coalesce to make more stars — and the stellar nurseries will go quiet.
 

Script by Damond Benningfield

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Big storms bring big rains at this time of year. It rains on the Sun, too, mainly during its own stormy season.

The Sun produces big magnetic storms on its surface. The number varies across an 11-year cycle. At its minimum, the Sun can be storm free for days or even weeks. But at its peak, the cycle can produce dozens of dark sunspots, plus many big outbursts of particles and radiation.

Those outbursts blast billions of tons of hot gas out into space. Some of that material escapes into the solar system, where it can affect Earth and the other planets. On Earth, it can knock down satellites, cause power blackouts, and block some forms of radio communications.

But some of it forms big loops that trace out a storm’s magnetic field. And much of that material can “rain” back down on the Sun.

A recent study looked at that hot rain. It was the first study to compare the length and intensity of the rainfall to the power of the storms. It found that the rain can last anywhere from an hour to more than three days. The longest rains were produced by the most powerful storms. And storms of low intensity produced little or no rain at all.

That suggests that studying the rainfall can tell us more about the energy produced by the storms themselves. It might also tell us more about the Sun’s long magnetic cycle, and even contribute to predictions of the intensity of coming cycles — helping forecast more rainfall on the surface of the Sun.
 

Script by Damond Benningfield

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A star cluster with a lot of deceptively young-looking stars ascends the eastern sky tonight. It’s to the upper left of the bright yellow-orange star Arcturus, which climbs into good view by about 10 o’clock. The cluster is visible through binoculars as a small, round, faint smudge of light.

Messier 3 is a tight ball of half a million stars known as a globular cluster. It spans a couple of hundred light-years, although most of its stars are jammed together in the middle. They’re so tightly packed that each star probably has thousands of neighbors within just five light-years; by comparison, only one star system is that close to the Sun.

Among M3’s myriad stars are many that appear to be much younger than they really are.

M3 probably was born more than 11 billion years ago. All of its most vigorous stars, which were bright and blue, have long since died. So the cluster’s remaining stars should be fairly red. Yet M3 contains quite a few blue stars, known as blue stragglers.

The leading ideas say these stars drank from a sort of stellar fountain of youth, making them look young again.

They probably have companion stars. In one possible scenario, the stars merge to form a single star, which would be hot and blue. In another scenario, one star dumps its cool, red outer layers onto its companion, making the recipient bluer.

Both processes appear to be at work in M3 — reinvigorating some old stars.
 

Script by Damond Benningfield

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Astronomers have discovered a new twist on an old galaxy. They’ve been studying M33, the Triangulum Galaxy, for more than 350 years. But a new study found that it’s not quite what it seems.

M33 is low in the west-northwest at nightfall, to the upper right of brilliant Venus, and is visible through binoculars. It’s more than two and a half million light-years away.

M33 has been considered a “flocculent” galaxy. That means it forms a disk with a lot of spiral arms and parts of arms. But when astronomers recently peered into the heart of M33 with Hubble Space Telescope, they found some surprises.

They plotted 22 million stars — old, young, and very young. And when they traced out those groups, they found three configurations.

The youngest stars, which tend to be brighter, formed the flocculent structure — spiral arms all over the place. The young stars mainly fell into two arms, connected by a bar of stars across the middle. And the older stars formed a flatter disk than the youngsters, with almost all of them in the two arms and the bar.

It’s impossible to tell what the galaxy looked like when it was born. It could have been hit or side-swiped by another galaxy fairly recently. That might have left the older stars in their original bar-and-two-arms arrangement. At the same time, it could have triggered the birth of new stars and created the many spiral arms we see today — a new twist to an old galaxy.
 

Script by Damond Benningfield

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Green Peas are like living fossils. Not the hard little nuggets that get overzapped in the microwave. These are small, busy galaxy nuggets. Astronomers have found several of them in the modern universe. But in its very first picture, James Webb Space Telescope found some in deep space — when the universe was less than a billion years old. That makes the close ones living fossils — as one astronomer described them, the coelacanths of galaxies.

Green Peas were discovered in 2007. They were fairly close — within a couple of billion light-years. They’re dense, round knots a few thousand light-years across — a few percent the size of the Milky Way. They’re giving birth to many stars. They get their color from the glow of hot gas — a lot of it. The combination of gas and rapid starbirth means they’re pristine — they’re just starting to take shape.

Webb discovered three Green Peas in its first picture of the deep universe, which covered a tiny fleck of sky. They’re the same size as the modern Green Peas. They have the same structure and composition. And they’re at the same stage in life — they’re just getting cranked up, so they’re giving birth to a lot of stars.

But these Green Peas are 13.1 billion years old. That means we’re seeing them as they looked when the universe was only 700 million years old.

So the modern Green Peas are like living fossils — modern versions of some of the first galaxies in the universe.
 

Script by Damond Benningfield

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Stars are big — really big. The Sun, for example, is more than a hundred times the diameter of Earth. But a few stars leave the Sun in the dust. Antares, the bright orange heart of the scorpion, appears to be about 700 times bigger. If the Sun were the size of an NBA basketball, then Antares would be bigger than the entire arena.

That size may not be constant, though. The star’s brightness can vary by a fair amount. That suggests that Antares is unstable, so it pulses in and out. Some studies say its diameter could vary by as much as 20 percent. Not to bury you in numbers, but that would be the equivalent of roughly 140 Suns.

Other studies suggest it’s not the whole star that changes. The changes in brightness aren’t regular, so there’s no way to predict when Antares will get brighter or fainter. That could mean that bubbles of hot gas many times bigger than the Sun are churning to the surface. New bubbles are hot and bright, so they could account for the change.

No matter what’s going on, it’s certain that Antares is one of the more massive stars in the galaxy. That means it’ll get a lot brighter at the end of its life. It will explode as a supernova, perhaps outshining the entire galaxy before its tiny corpse fades into the cosmic night.

Look for Antares near the Moon in the early morning sky. It’ll stand to the left or lower left of the Moon at dawn tomorrow, and to the right of the Moon on Tuesday.
 

Script by Damond Benningfield

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It’s time for an annual ritual: spring forward. Tonight, we set our clocks ahead by an hour as we switch to Daylight Saving Time.

The idea was first proposed in the 19th century. Germany and Austria-Hungary became the first countries to adopt it, in 1916.

The United States took it up late in World War I. The idea was that extending evening daylight would reduce energy usage, providing more resources for the war effort. And during World War Two, it was implemented year-round, with a two-hour difference from Standard Time.

After the war, states were free to do what they wanted. But in 1966, Congress passed rules for the whole country. States could opt out — Arizona and Hawaii still do — but they couldn’t implement DST year-round.

Today, the pluses and minuses of Daylight Saving Time are hotly debated. Some studies suggest there’s a slight decrease in energy usage, but others find no difference. Other studies find an increase in health problems, such as the risk of heart attack — but others don’t. And still other studies have reported evidence of more car accidents, while others find no change at all.

But the change always brings complaints — especially in the spring, when we lose an hour of sleep. Last year, the U.S. Senate passed a bill to make the change year-round, but it died in the House. So for now, most of us will keep springing forward in March, and falling back in November.
 

Script by Damond Benningfield

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The Orion Nebula is one of the most remarkable regions in our part of the galaxy. It’s a giant complex of clouds of gas and dust that are forming new stars. So far, it’s given birth to thousands of them, of all sizes. And many more are taking shape even now. But some of those stars are starting to shut down the process.

Astronomers looked at the nebula with SOFIA, an airborne observatory that was retired in September. In particular, they looked at what was happening at the rim of a giant bubble. It surrounds the Trapezium, a small group of especially hot, bright, massive stars.

Radiation and strong “winds” from those stars created the bubble in the first place, blowing away the surrounding gas and dust. The SOFIA observations showed that today, the Trapezium is producing big outflows of hot gas — like interstellar rivers. The outflows are drilling thousands of tiny holes in the bubble — making the rim as porous as a sieve.

As gas flows out of those holes, it rams into material outside the bubble. That blows away some of the gas and dust that might otherwise make more stars — helping shut down starbirth in the Orion Nebula.

The nebula is well up in the south as night falls, below Orion’s three-star belt. Under mildly dark skies, it’s visible to the unaided eye as a hazy smudge of light. It’s easier to see if you look at it out of the corner of your eye — the combined fires of thousands of young stars.
 

Script by Damond Benningfield

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