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Showing posts with label stars. Show all posts
Showing posts with label stars. Show all posts

A Trio of Stars


Apep is a trio of stars with distinct shells of dust swirling around them. Images taken by the James Webb Space Telescope are the crispest view we have of the star system to date. 

Apep is one of those rare places in the galaxy where chaos and abundance seem to spill out in equal measure, almost like a cosmic cornucopia. From far away it looks like a single star, but Webb’s astonishingly sharp mid‑infrared view reveals something far richer: three stars bound together, two of them belonging to the extraordinarily rare Wolf‑Rayet family. These stars are massive, hot, and nearing the end of their lives, shedding material so quickly that their surroundings glow with the dust they cast off. Only about a thousand Wolf‑Rayet stars exist in our entire galaxy, yet Apep contains two of them orbiting each other, with a third supergiant star circling farther out. It’s a stellar arrangement so unusual that astronomers haven’t found another like it.

Before the James Webb Space Telescope, telescopes could make out only a single swirl of dust around Apep. Webb changed that instantly. Its mid‑infrared vision peeled back the darkness and revealed four distinct shells of dust, each one a shimmering layer drifting outward like the rings of a slowly expanding onion. These shells form because the central pair of stars moves in a long, looping orbit that takes 190 years to complete. For a brief window of that orbit—about twenty‑five years—the stars pass close enough to each other to unleash a burst of dust that races outward at thousands of miles per second. Over centuries, these bursts stack up, creating layer after layer of cosmic sculpture.


The beauty of Apep’s spirals is complicated by the presence of the third star. Its powerful stellar winds slice through the expanding dust like a blade, carving gaps and slashes into the shells. The result is a pattern that looks both delicate and turbulent, as if the universe were painting with fire and wind at the same time. Even the faintest outer shell, barely visible at the edge of Webb’s detection, adds to the sense that this system is overflowing with material—an astronomical horn of plenty.

It’s tempting to see Apep as just a distant spectacle, but its story reaches all the way to us. The dust pouring from these stars is rich in the heavy elements that make planets, oceans, and living things possible. When stars like these eventually explode as supernovae, they scatter those elements across space, seeding future generations of stars and worlds. The carbon in our cells and the iron in our blood were forged in the hearts of dying stars, much like the ones in Apep. Studying this system is, in a way, studying our own origins.


Cornucopia

Apep also helps scientists understand some of the most energetic events in the universe. One of its stars may eventually produce a gamma‑ray burst, an explosion so powerful it can reshape the space around it. Apep is far too distant to pose any danger to Earth, but learning how these events work is essential for protecting future astronauts and satellites from high‑energy radiation elsewhere in the galaxy. And beyond the science, there’s something deeply human about the fact that we can see faint dust shells drifting through space from 8,000 light‑years away. Webb’s clarity is a reminder of what curiosity and collaboration can achieve.

In the end, Apep is a portrait of cosmic generosity. Even as its stars approach their final act, they are pouring material into the galaxy, enriching the space around them, and shaping the future long after they’re gone. 

It’s chaos, yes—but it’s also creation, abundance, and the quiet truth that the universe is always giving more than it takes.

Occulations

An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks from view (occults) an object in the background. 

Occultations are regular, predictable events because planets, dwarf planets, moons, and asteroids orbit the Sun and pass in front of stars in the background.

The term occultation is most frequently used to describe lunar occultations. These are not uncommon occasions when the Moon passes in front of a star, planet, or other heavenly body during the course of its orbital motion around the Earth. Occultations of bright stars and planets typically occur a few times per year, often clustering with several occultations of the same object in successive months, since the Moon traces roughly the same path across the sky each month.

But occultations also occur when a moon passes another moon, or a planet passes another planet. Mutual occultations or transits of planets are extremely rare. The most recent event occurred on 3 January 1818, and the next will occur on 22 November 2065. Both involve the same two planets: Venus and Jupiter.

Saturn Occultation.gif
Saturn occultation CC BY-SA 2.0 at, Link


A grazing occultation of Rhea (a large moon of Saturn)
by another of its moons, Dione. Image: assini–Huygens


Islands of Stars

Milky Way Galaxy


Until 1924,  the Milky Way galaxy - our galaxy - represented the entirety of the universe. That year, astronomer Edwin Hubble announced the discovery of other galaxies.

Hubble was studying the Andromeda Nebula at Mount Wilson observatory in California, — the most powerful telescope in the world at that time. He was able to to distinguish individual stars within the nebula.

One of the stars he observed is called a Cepheid variable. This is a type of star that pulsates and is very bright and that by observing and measuring its brightness and the length of time it takes to go from bright to dim and back again, one could calculate the star’s distance from the Earth. 

Hubble calculated that the star he was observing was 800 thousand light-years away, more than eight times the distance of the farthest star in the Milky Way, and so he realized that the “cloud of gas” he’d been observing was really another vast galaxy that was very far away. He renamed the Andromeda Nebula the Andromeda Galaxy.

Hubble would discover 23 more separate galaxies. Our Milky Way galaxy is just one of many little islands of stars.

Andromeda Galaxy


The Moon, Jupiter and Spica

This Memorial Day Weekend, from May 25 to 28, we had some clear skies and some rainy ones. Tonight should be clear in my neighborhood and I will be able to see a very bright “star” near the moon. But it is not a star. It is Jupiter.

Venus sets in the west not too long after the sun had set, and the Moon and Jupiter were the two brightest objects in the sky.

I knew to look for a fainter true star. It is fainter but still one of the brightest stars, even in moon’s glare. This is Spica. It is the brightest star in the constellation Virgo the Maiden. I'm not very knowledgeable about the zodiac, but I know it is a key star in that study.

Spica is a first-magnitude star, but it appears much fainter than Jupiter. That is because Jupiter is relatively close (or at least nearer)to Earth. This is what draws me to gazing at the night sky is my semi-knowledgeable way: the idea that Spica is about 262 light-years away, and I am looking at its light.

The universe makes me think about the first meanings of words like WONDERful and AWEsome.


Spica is the easiest star to spot in Virgo. There is a saying to find Spica you can "follow the arc of the Big Dipper to Arcturus and speed on to Spica." But that probably doesn't make it any easier for the average Earthling to find because most people know very little about the night sky.

Besides Spica, other bright stars in Virgo include many I had never heard of: β Virginis (Zavijava), γ Virginis (Porrima), δ Virginis (Auva) and ε Virginis (Vindemiatrix). Other fainter stars that were also given names are ζ Virginis (Heze), η Virginis (Zaniah), ι Virginis (Syrma) and μ Virginis (Rijl al Awwa).

Again, the wonder and awe of all this is discovering that one of the stars, 70 Virginis, has one of the first known extrasolar planetary systems and it contains a confirmed planet 7.5 times the mass of Jupiter. I can't even really grasp the size of my own Earth. And the star Chi Virginis has one of the most massive planets ever detected, at a mass of 11.1 times that of Jupiter. And there are 35 verified exoplanets orbiting 29 stars in Virgo.

All this makes me feel like such a small part of the universe. But it makes me feel like part of he universe. I feel better knowing these things.