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Globular Cluster - Blog Posts
Say hello to globular cluster 47 Tucanae 👋
This glittery spray of ancient stars is about 16,700 light-years away from Earth toward the constellation Tucana. Globular clusters like this one are isolated star cities, home to hundreds of thousands of stars that are held together by their mutual gravity. And like the fast pace of cities, there's plenty of action in these stellar metropolises. The stars are in constant motion, orbiting around the cluster's center.
Past observations have shown that the heavyweight stars tend to crowd into the “downtown” core area, while lightweight stars reside in the less populated suburbs. But as heavyweight stars age, they rapidly lose mass, cool down and shut off their nuclear furnaces. After the purge, only the stars' bright, superhot cores – called white dwarfs – remain. This weight loss program causes the now lighter-weight white dwarfs to be nudged out of the downtown area through gravitational interactions with heftier stars.
Until these Hubble observations, astronomers had never seen the dynamic conveyor belt in action. The Hubble results reveal young white dwarfs amid their leisurely 40-million-year exodus from the bustling center of the cluster.
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The glittering globular cluster Terzan 12 — a vast, tightly bound collection of stars — fills the frame of this image from the NASA/ESA Hubble Space Telescope. This star-studded stellar census comes from a string of observations that aim to systematically explore globular clusters located towards the centre of our galaxy, such as this one in the constellation Sagittarius. The locations of these globular clusters — deep in the Milky Way galaxy — mean that they are shrouded in gas and dust, which can block or alter the wavelengths of starlight emanating from the clusters.
Here, astronomers were able to sidestep the effect of gas and dust by comparing the new observations made with the razor-sharp vision of Hubble's Advanced Camera for Surveys and Wide-Field Camera 3 with pre-existing images. Their observations should shed light on the relation between age and composition in the Milky Way’s innermost globular clusters.
[Image Description: The frame is completely filled with bright stars, ranging from tiny dots to large, shining stars with prominent spikes. In the lower-right the stars come together in the core of the star cluster, making the brightest and densest area of the image. The background varies from darker and warmer in colour, to brighter and paler where there are more stars.]Credit:
ESA/Hubble & NASA, R. Cohen (Rutgers University)
A stellar exodus was caught in action! Astronomers used the Hubble Space Telescope to watch the white dwarf exodus in the globular star cluster 47 Tucanae, a dense swarm of hundreds of thousands of stars in our Milky Way galaxy. Hubble took snapshots of fledgling white dwarf stars beginning their slow-paced, 40-million-year migration from the crowded center of an ancient star cluster to the less populated suburbs. By observing ultraviolet light, astronomers examined 3,000 white dwarfs, tracing two populations with diverse ages and orbits. One grouping was 6 million years old and had just begun their journey. Another was around 100 million years old and had already arrived at its new homestead far from the center, roughly 1.5 light-years, or nearly 9 trillion miles (14 trillion kilometers), away. The cluster resides 14,500 light-years away in the southern constellation Tucana. Credit: NASA, ESA, and H. Richer and J. Heyl (University of British Columbia, Vancouver, Canada). ALT TEXT: Thousands of stars, seen as tiny dots, are shown on a black background. The stars vary in size and color, including orange, yellow, and white.
NGC 4590 (M68) Globular Cluster
33,000 light years from the Earth, this globular cluster has an odd orbit around our galaxy, orbiting like a comet does around a star, and moving away as far as 100,000 light years from the centre.
It’s theorised that it’s likely a captured cluster, and appears to be undergoing core collapse, where the gravitational influence of the entire cluster bares down at the centre and causes black holes and dense stars to slowly migrate towards the centre, much as our own galaxy has the same mechanism creating the central black hole.
MESSIER 56 The NASA/ESA Hubble Space Telescope captured this image of Messier 56 (also known as M 56 or NGC 6779), located about 33,000 light years away from Earth in the constellation of Lyra (The Lyre). The stars in the globular cluster are tightly bound together by gravity.
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A ten billion-year stellar dance by europeanspaceagency
Pictures of the Day 2 - December 30, 2018
Here we come across an Earth-like world with violet hued skies. This planet supports marine life and orbits a star within a globular cluster. There are 137 star systems just within 5 light years of this planet, and the planet’s sky is lit up with their light. Most of the stars are close enough to be visible during the day. Additionally, this planet is located within a quandary star system consisting of an K type orange dwarf orbited three smaller red dwarfs in a wide complex orbit.
While Earth-Like, there are notable differences from Earth. First, the planet has almost no obliquity meaning it has no axial tilt and therefore does not experience seasons. Massive ice caps cover both poles. The planet also spins very slowly with a solar day lasting almost 3.86 Earth days. Only 4 small asteroid moons orbit the planet. Additionally, life is limited to the oceans, and the atmosphere is almost entirely made up of carbon dioxide.
Space Engine System ID: RSC 5581-4-4-2706-51 A4 to visit the system in Space Engine.
Planet Stats Below:
Radius: 5,268.61 km (0.83 x Earth) Mass: 0.59 Earth Masses Orbital Distance: 0.43 AU Length of Year: 118.88 Days Length of Solar Day: 3.86 Days Gravity: 0.86 g Average Temperature: 277 K (39° F) Atmospheric Pressure: 0.52 Atmospheres Atmospheric Composition: 92.7% Carbon Dioxide, 4.23% Nitrogen, 3.02% Oxygen, 0.05% Sulfur Dioxide.
Picture of the Day - December 30, 2018
Globular cluster. Almost 10,000 stars packed into a sphere just 100 light years across.
Starry Night
Picture of the Day - October 16, 2018
The sands of a desert world with the sky full of bright stars. This planet orbits a star located within a globular cluster; therefore, many bright stars punctuate the night sky. The bright star near the lower left is the planet’s sun, which is barely discernible from other stars in the sky,
Crowded Worlds
Picture of the Day - October 15, 2018
Alien moon and its parent gas giant, looking towards the sun. This system is located within one of the densely packed globular clusters orbiting Triangulum’s center.