StarDate

Many stars have beautiful, even romantic names, such as Antares and Aldebaran, Vega and Altair. But some stars have names that aren’t romantic at all. Instead, they’re downright funny. Two examples shine faintly in the southern constellation Lupus, the wolf.

Many star names incorporate the genitive case of their constellation. That’s why the brightest star in Centaurus is not Alpha Centaurus, but instead Alpha Centauri.

For a star whose brightness fluctuates, the name usually starts with one or two letters before the constellation name.

For example, RR Lyrae is a famous variable star in the constellation Lyra.

For the variable stars in Lupus, though, these rules lead to some unintentional humor. The genitive form of Lupus is L-U-P-I, pronounced just like the word “loopy.” So there’s a variable star in Lupus named IM Lupi and another named RU Lupi. If you’re not too squeamish about grammar, there’s also IR Lupi. And if you read the letters as a word, you can add “BE” Lupi and “GO” Lupi.

The light from IM Lupi and RU Lupi varies because they’re newborns that are shrouded in the clouds of gas and dust that gave them birth. They’re so young that they may not even have planets yet, let alone intelligent beings that call these stars their own.

That’s probably a good thing, because any residents might not be too thrilled that we Earthlings have given their stars such “loopy” names.

Script by Ken Croswell

The Orion Nebula is about 1500 light-years away, yet it’s easily visible to the unaided eye. It’s a complex of thousands of newborn stars. But it shines so brightly thanks mainly to just one of those stars. It’s a member of the most impressive class of stars in the galaxy — class “O.”

O stars are the hottest, brightest, and heaviest stars in the galaxy. Their high surface temperatures make them shine blue-white.

An example is the bright star at the heart of the Orion Nebula, known as Theta-1 Orionis C-1. It’s probably more than 30 times the Sun’s mass and 20 times its diameter. Combined with its temperature, that makes it a quarter of a million times brighter than the Sun.

O stars usually are found in stellar nurseries, such as the Orion Nebula. That’s mainly because they live for only a few million years — not enough time to move far from where they were born.

While they’re there, they have a major impact on the surrounding nebula. Their radiation causes the surrounding gas to glow. The radiation also evaporates much of the surrounding gas and dust. That can shut down the process of starbirth around the star. But the star’s radiation and winds can squeeze nearby clumps of gas and dust, causing them to give birth to new stars.

O stars also create many of the chemical elements. At the ends of their lives, the stars explode, scattering the elements into space. That provides the raw materials for new stars, planets — and perhaps life.

Script by Damond Benningfield

The hottest and brightest stars in the galaxy also are the rarest — they account for about one of every 10 million stars. Yet they’re so dazzling that several of them are visible to the unaided eye.

Astronomers classify these stars as class “O.” They’re at the top of a system that uses the letters O, B, A, F, G, K, and M.

An O star that’s in the prime of life can be anywhere from about 20 to more than a hundred times as massive as the Sun. Because of that great heft, the nuclear reactions that power the star take place at a furious rate. Energy from those reactions makes the surface of the star tens of thousands of degrees hotter than the Sun, which makes the star look blue-white.

The star also looks tens of thousands of times brighter than the Sun. Because of its temperature, though, most of its energy is in the ultraviolet. When you add that to the visible light, the brightest O stars can shine up to a million times brighter than the Sun.

The Milky Way’s population of O stars is probably about 20,000 — out of a total of hundreds of billions of stars. In part, that’s because the galaxy gives birth to far more small stars than big ones. But it’s also because an O star lasts only a few million years. When its nuclear fuel is gone, the star’s core collapses to form a black hole or a neutron star. The star’s outer layers may then explode as a supernova — briefly adding to the luster of these already lustrous stars.

More tomorrow.

Script by Damond Benningfield

No matter how much we know about the universe, we can always learn more. An example is a star that blazes at the middle of a stellar nursery in the constellation Puppis. When it was first seen, through a telescope, it looked like a single star. Later, it turned out to be two stars. And now, it looks like the system may consist of at least four stars, all of which are far bigger and brighter than the Sun.

The system is known by a catalog name — HD 64315. It’s about 16,000 light-years away. Large telescopes show two stars, which are separated by tens of billions of miles. And a spectroscope, which breaks a star’s light into its individual wavelengths, shows that each of those stars actually consists of two stars. It’s one of the most fascinating systems in the entire galaxy.

A recent study says that in the brighter binary, both stars are probably more than 30 times as massive as the Sun. And they’re so close together that they’re almost touching.

The stars of the other binary are touching each other —they share their outer layers of gas. The stars are almost exactly the same size and mass — about 15 times as heavy as the Sun. But within the next 25,000 years or so, they may merge. That’ll form a single star that’s as big as those in the other binary.

After that, HD 64315 will consist of three supergiant stars, each of which will someday explode as a supernova — one more change for this busy star system.

Script by Damond Benningfield

One of the problems with looking out into the universe is that we don’t have any depth perception — everything looks two-dimensional. That makes it hard to tell how far things are. And that can make it hard to tell if something is a single object, or several overlapping ones.

An example is a nebula known as NGC 2467. It’s in the constellation Puppis, which is low in the south on spring evenings. The nebula is well to the left of Sirius, the brightest star in the night sky, and is visible through binoculars.

The nebula looks like a single stellar nursery. It turns out, though, that it consists of several objects that happen to line up in the same direction. Two of them are clusters of young stars. The third contains both stars and the raw material for making more stars.

This third cluster is dominated by what looks like a single light — a star system that is tens of thousands of times brighter than the Sun. The system actually consists of at least four stars; more about that tomorrow.

The four stars are all quite hot, so they produce lots of ultraviolet radiation. That energy lights up the surrounding nebula. The UV vaporizes the gas and dust around the system, shutting down star formation. But it also creates a wave that pushes outward, compressing clouds of gas and dust and causing them to form more stars. In fact, a recent study found 45 stars that are being born along that wave — new life in a distant stellar nursery.

Script by Damond Benningfield

A legendary boat sails low across the south at this time of year: the Argo, which carried Jason and the Argonauts on the quest for the golden fleece. You won’t find it on any modern starcharts, though. Instead, you’ll find its parts, which form three constellations: Puppis, the stern; Vela, the sail; and Carina, the keel.

It was a constellation in ancient times, though, known as Argo Navis. It may have been adopted from ancient Egypt, where the stars represented the boat that carried a statue of Osiris, the god of the underworld, during an annual festival.

The Greeks decided to make the boat their own. They associated its stars with the tale of Jason. His uncle stole the throne from him, but promised to give it back if Jason would bring him the fleece of a magical ram.

So Jason had the shipbuilder Argus make him a sturdy boat. And he manned it with 50 heroes, including Hercules and the twins of Gemini. The boat, known as the Argo, carried them safely through many harrowing adventures.

The constellation honoring the boat was named more than 2500 years ago. It was the largest of all the ancient constellations. Astronomers later decided that it was too big. In the 17th century, Nicolas Louis de Lacaille split it into three parts. They weren’t accepted by everyone, though, until 1930, when an international group established the constellation borders that we use today — including those of the dismembered pieces of the Argo.

More tomorrow.

Script by Damond Benningfield

The subtle band of the Milky Way arcs low across the west this evening. It sweeps from Sirius, the brightest star in the night sky, in the southwest, through Orion, and over to W-shaped Cassiopeia low in the northwest.

Under dark skies, you can see the glow of the Milky Way suffusing this collection of sparklers. As you look away from that band, though, things get darker. There are wide sections of sky with no bright stars, and not many faint ones, either.

Consider Camelopardalis, which is above Cassiopeia at nightfall. The constellation represents a camel with the spots of a leopard, hence its name — the camel-leopard.

From a light-polluted city, you won’t be able to spot any of its stars at all — they’re just too faint. And you need dark skies — dark enough to see the Milky Way — to see the stick figure outlined by the camel-leopard’s stars.

As you look in that direction, you’re beginning to look away from our home galaxy and toward intergalactic space. And a small telescope will reveal several galaxies.

The brightest is NGC 2403. It’s a fuzzy spiral galaxy about 10 million light-years away. It’s maybe half the diameter of the Milky Way. And it’s packed with bright clusters that are giving birth to many new stars. The heaviest of these stars live short, brilliant lives, then explode as supernovae. In fact, a supernova was seen on the outskirts of the galaxy back in 2004 — a rare bright spot in the intergalactic darkness.

Script by Damond Benningfield

Clouds are a common sight at this time of year, as thunderstorms erupt across much of the country. Big clouds also can darken the skies on Mars — clouds made not of water, but of dust. In fact, some Mars experts predict that a giant dust storm could develop later this year, and last for weeks or months.

There’s dust in the Martian atmosphere all the time. As much as half of it may be stirred up by dust devils — tall, whirling columns like those seen in deserts here on Earth. They can splash dust high into the atmosphere, where it may circulate around the entire planet.

Mars also produces dust storms. Most of them are regional — they cover thousands of square miles, usually in the northern hemisphere. Their dust can remain in the sky for a long time, too. And every few years, a storm turns into a monster — it can cover most of the planet. That could happen later this year — a storm that could darken the skies across all of Mars.

As the dust swirls into the sky, it also carries water vapor. At high altitudes, sunlight splits the water molecules apart. The water’s lighter hydrogen atoms then may be blown out into space, slowly depleting the Martian atmosphere.

And Mars is easy to find early tomorrow. It stands to the right of the Moon at first light, and looks like a bright orange star — its surface colored by the same dust that dirties its sky. Saturn is close to the upper right of Mars, completing a beautiful display in the dawn sky.

Script by Damond Benningfield

The night will get a lot brighter after about 2 or 3 o’clock tomorrow morning, as the gibbous Moon climbs into good view. But it won’t be nearly as bright as the nightside of a planet that appears quite close to the Moon: Saturn, the second-largest planet in the solar system. It’s just below the Moon as they rise, and looks like a bright star.

The Moon brightens the night sky by reflecting sunlight in our direction. Saturn’s night is brightened by reflected sunlight as well — from its brilliant rings.

The rings extend tens of thousands of miles from Saturn. That gives them a surface area of hundreds of millions of square miles. And the rings are made mainly of small bits of ice, which reflect a lot of sunlight. That combination makes them quite bright. In fact, as seen from here on Earth, the rings can be as bright as Saturn itself.

Around the solstices on Saturn, the rings are tilted in such a way that they reflect a lot of sunlight onto Saturn’s nightside. So nighttime can be brighter than a night under a full Moon here on Earth. And there was a solstice recently, so that’s what Saturn is experiencing right now.

Around the planet’s equinoxes, though, the rings are tilted almost edge-on to the Sun. They don’t catch much sunlight, so they can’t reflect it back onto the planet — leaving Saturn with dark night skies.

Another planet is also close to the Moon: Mars, which is just below Saturn as they rise. More about that tomorrow.

Script by Damond Benningfield

Star clusters are some of an astronomer’s best friends. All of the stars in a cluster were born at the same time, from the same parent cloud of gas and dust. So any differences between the stars must be caused by what’s happening inside the stars themselves. That makes clusters excellent laboratories for studying how stars evolve.

Clusters also can be good laboratories for studying the birth and evolution of planets. And astronomers have found several planets in the Hyades, a cluster that forms the V-shaped face of Taurus, the bull.

They’ve found a giant planet orbiting the giant star Epsilon Tauri, for example. The planet is about seven times the mass of Jupiter, the giant of our own solar system.

Three planets orbit a star in a binary system. The star is a bit smaller than the Sun, and only about 15 percent as bright. One of its planets is the size of Earth, one is a bit bigger than Earth, and the third is almost as big as Neptune. The Earth-size planet is quite close to the star, though, so it’s too hot to be a good home for life. Even so, studying this system may reveal more about how planets are born, and how planetary systems evolve.

Look for the Hyades about a third of the way up the western sky at nightfall, forming a letter V. The brightest star in the V is Aldebaran, the bull’s eye. It’s not actually a member of the Hyades. But the other bright stars of the V are — members of an astronomical laboratory.

Script by Damond Benningfield