Posts Tagged ‘dwarf galaxy’

Insectoid Head of Stars

NASA/ESA Hubble

An insect-shaped head emerges from the jumble of stars in this image from the NASA/ESA Hubble Space Telescope of irregular dwarf galaxy DDO 190.

Explore the crowded jumble of stars. What pictures or stories do you see? Leave a note in the comments below.

DDO 190 is called a dwarf irregular galaxy because it lacks clear structure. Unlike a spiral galaxy, like our own Milky Way Galaxy, DDO 190 has no spiral arms. Starting from the outskirts of the small galaxy, older, reddish stars dominate the scene. But as we move inward, younger, blue stars begin to appear. Pockets of glowing gas, areas where new stars are being created, dot the entire galaxy. The most noticeable of these is the butterfly-shaped area at the bottom (what makes the mouth of our head in my imagination).

Scattered throughout the image look for more distant galaxies; galaxies with more regular spiral or elliptical shapes and indistinct shapes.

DDO 190 is within the Messier 94 galaxy group but it is fairly alone in its area of space. While our Milky Way has many companions, such as the Large and Small Magellanic Clouds, and the relatively nearby Andromeda Galaxy at two million light-years away, DDO 190 is alone. The closest galaxy to this tiny dwarf galaxy is thought to be no more than three million light-years away. DDO 190, discovered by Canadian astronomer Sidney van der Bergh in 1959, is found about 9 million light-years from Earth toward the constellations Canes Venatici (Hunting Dogs) and Coma Berenices (Queen Berenice’s Hair).

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Faces in a Faint Cloud

Credit: ESA/NASA Hubble

 

Eyes peer out of this faint star cloud known as the Antlia Dwarf Galaxy in this image from the NASA/ESA Hubble Space Telescope.

Zoom into the sparsely populated star cloud. What faces or stories do you see? Leave a note below.

Discovered recently in 1997, the Antlia Dwarf Galaxy is a very faint collection of stars just four million light-years from Earth. Although it is somewhat close, it is unclear whether it is part of the Local Group, a group of galaxies containing the Milky Way Galaxy, Magellanic Clouds and the Andromeda Galaxy. The Antlia Dwarf Galaxy may be just wandering near the group interacting slightly with nearby galaxies. Astronomers study galaxies like this one because it gives them a clear picture of different stages of galaxy formation.

Zoom into the loose galaxy. New, bluer stars are found toward the center of the image. Older red stars and faint, fuzzy globular clusters are found to the outside. In the background, gaze at dozens of faraway galaxies of different shapes. Perhaps one of those distant galaxies has a faint dwarf galaxy nearby that we cannot see.

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Pink Puffs

Credit: ESA/Hubble & NASA

Pink puffs of cloud created by supernovae explosions dominate this image from NASA’s Hubble Space Telescope.

Explore the glowing bubbles of IC 2574. What stories or patterns do you see? Leave a note below.

IC 2574 is also known as Coddington’s Nebula after American astronomer Edwin Coddington who discovered the galaxy in 1898. The pink shells of gas blown open by the supernovae are surrounded by blue stars. Supernovae explosions send shockwaves throughout the surrounding dust clouds smashing material together. This compression can cause new stars to form. The pink color comes from hydrogen gas that glows because of blistering radiation from the newborn stars.

Astronomers classify IC 2574 as a dwarf irregular galaxy. Instead of a clear structure, like the spiral structure of M51, IC 2574 has no organization. Astronomers study these types of galaxies because they give a hint at the earliest galaxies that formed in the Universe. Faraway in the background, look for the glow of scattered galaxies.

IC 2574 is found about 13 million light-years from Earth toward the constellation Ursa Major, the Great Bear or the Big Dipper. The small galaxy is part of the Messier 81 group of galaxies.

A snortful of stars

Credit: ESA/Hubble & NASA

Two galactic eyes peering over a smushed nose resembles a manatee in this image from the NASA/ESA Hubble Space Telescope.

Explore the image of dwarf irregular galaxy known as UGC 9128. See a shape or story in this image? Leave a note below.

UGC 9128 falls into an unusual category of galaxy. While some galaxies have highly regular spiral or elliptical shapes, irregular galaxies can look like a smashup of stars. But as messy as these galaxies look, scientists have found they share many common traits with their big brothers. Astronomers used UGC 9128 to find halos of older stars and star clusters as well as a central disk filled with younger stars. Dwarf galaxies are important to scientists studying how galaxies evolve.

UGC 9128 contains only about 100 million stars. That’s a small number compared with the billions of stars found in our own Milky Way. As you probe deep into the irregular galaxy, look at the number of hot blue stars. These stars have just recently formed. As you zoom out, two lobes begin to stand out. And across the entire image, gawk at hundreds of far-off galaxies.

Faint UGC 9128 lies only about 8 million light-years from Earth; right in the backyard, toward the constellation Boötes, The Herdsman. Discovered in the 20th century, it is one of more than 30 nearby galaxies known as the Local Group that also includes Milky Way Galaxy, Large and Small Magellanic, Andromeda Galaxy, and Triangulum Galaxy. UGC stands for Uppsala General Catalogue of Galaxies. The catalog, first published in 1973, includes 12,921 galaxies seen from the northern hemisphere.

Starry Bug

Credit: NASA & ESA

Floating like a bug under a microscope, I Zwicky 18 is an odd-looking galaxy. Astronomers previously thought this peculiar galaxy was very young because it resembles galaxies typically found in the early universe. But images from NASA‘s Hubble Space Telescope show older stars within the galaxy leading scientists to update their ideas. They now believe I Zwicky 18 was born about the same time as the Milky Way Galaxy and the Andromeda Galaxy.

Explore the image of this dwarf irregular galaxy. It is much smaller than the Milky Way and has more in common with the Magellanic Clouds. Look for the knots of blue-white stars. New stars are forming at furious rates within these starburst regions. Bubbles of wispy blue gas surround the starburst areas. Supernovae and strong solar winds from the new stars blow away gas and dust forming these wispy bubbles. Intense ultraviolet radiation causes the whole star cloud to glow. In addition to the new, blue-white stars, look for reddish stars in I Zwicky 18 and the companion galaxy nearby. These reddish stars are more than 10 billion years old; more than twice the age of our own Sun. The companion galaxy may be tugging on I Zwicky 18 and causing the recent star formation.

Farther away in this image, you can see ancient fully-formed elliptical galaxies as well as edge-on and face-on spiral galaxies. I Zwicky 18 is about 60 million light-years from Earth toward the constellation of Ursa Major the Great Bear.

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The ancient peoples saw pictures in the sky. From those patterns in the heavens, ancient storytellers created legends about heroes, maidens, dragons, bears, centaurs, dogs and mythical creatures...
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