The NASA/ESA Hubble Space Telescope has been observing the V838 Mon light echo since 2002. Each new observation of the light echo reveals a new and unique “thin-section” through the interstellar dust around the star. This video morphs images of the light echo from the Hubble taken at multiple times between 2002 and 2006. The numerous whorls and eddies in the interstellar dust are particularly noticeable. Possibly they have been produced by the effects of magnetic fields in the space between the stars.
This Hubble Space Telescope image shows galaxy NGC 4485. Located about 25 million light-years away in the constellation Canes Venatici, this galaxy was once a spiral. Now it has an irregular shape, the result of interactions with nearby NGC 4490, which lies out of image to the bottom right of the frame. The pair of galaxies, together known as Arp 269, are putting distance between themselves now, having made their closest approach to each other long ago.
In addition to the warped shape this spiral took on from this close passage with NGC 4490, it sports a trail of bright stars and clumps of gas and dust to the lower right. It is a tenuous bridge stretching some 24,000 light-years across space, the last loose connection between the pair.
There are other vestiges from this cosmic fling. As they passed by each other, vast fields of hydrogen gas were shared between them. The intermixing clouds created waves of new star formation, the progeny of this cosmic romance. The starburst activity is ongoing, with the newest stars forming within the orange knots of gas and dust.
Image credit: ESA/Hubble & NASA
They say the flap of a butterfly’s wings can set off a tornado on the other side of the world. But what happens when a butterfly flaps its wings in the depths of space?
This cosmic butterfly is a nebula known as AFGL 4104, or Roberts 22. Caused by a star that is nearing the end of its life and has shrugged off its outer layers, the nebula emerges as a cosmic chrysalis to produce this striking sight. Studies of the lobes of Roberts 22 have shown an amazingly complex structure, with countless intersecting loops and filaments.
A butterfly’s life span is counted in weeks; although on a much longer timescale, this stage of life for Roberts 22 is also transient. It is currently a preplanetary nebula, a short-lived phase that begins once a dying star has pushed much of the material in its outer layers into space, and ends once this stellar remnant becomes hot enough to ionise the surrounding gas clouds and make them glow. About 400 years ago, the star at the centre of Roberts 22 shed its outer shells, which raced outwards to form this butterfly. The central star will soon be hot enough to ionise the surrounding gas, and it will evolve into a fully fledged planetary nebula.
Image credit: NASA, ESA, and R. Sahai (Jet Propulsion Laboratory)
“Eta Carinae is a highly luminous hypergiant star. Estimates of its mass range from 100 to 150 times the mass of the Sun, and its luminosity is about four million times that of the Sun.
This object is currently the most massive star that can be studied in great detail, because of its location and size. Several other known stars may be more luminous and more massive, but data on them is far less robust. Stars with more than 80 times the mass of the Sun produce more than a million times as much light as the Sun. They are quite rare—only a few dozen in a galaxy as big as ours—and they flirt with disaster near the Eddington limit, i.e., the outward pressure of their radiation is almost strong enough to counteract gravity. Stars that are more than 120 solar masses exceed the theoretical Eddington limit, and their gravity is barely strong enough to hold in its radiation and gas, resulting in a possible supernova or hypernova in the near future.
Eta Carinae’s effects on the nebula can be seen directly. The dark globules in the above image and some other less visible objects have tails pointing directly away from the massive star. The entire nebula would have looked very different before the Great Eruption in the 1840s surrounded Eta Carinae with dust, drastically reducing the amount of ultraviolet light it put into the nebula.”
Credit: ESO/Digitized Sky Survey 2.
Acknowledgment: Davide De Martin.
Heard About Star Stuff? Not yet? This is probably the best time! Star stuff Episode 662 is now out!
Listen to it on the best ABC radio stations across Australia.
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This week’s show…..
Oldest Star Discovered
Australian astronomers have found the oldest star ever seen. The Methuselah like star is 13.6 billion years old. It was identified by its extremely low iron spectra.
The re-ionization epoch seen in a new light
Scientists now have a better picture of an important episode in ancient cosmic history known as the re-ionization epoch. Using new computer simulations, astronomers in Israel found that the universe heated up more slowly than previously thought.
A new way to track near Earth asteroids
The dream of detecting every potentially dangerous near Earth asteroid could be a step closer to reality, thanks a new technique called synthetic tracking. Tests show the new system might be able to find any asteroid over seven meters wide which comes into its field of view.
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