Category Astronomy/Space

Rare Sighting of Luminous Jet Spewed by Supermassive Black Hole

Image credit: Zwicky Transient Facility/R.Hurt (Caltech/IPAC).

What happens when a dying star flies too close to a supermassive black hole? Astronomers discover a bright optical flare caused by a dying star’s encounter with a supermassive black hole.

According to University of Maryland astronomer Igor Andreoni, several things happen: first, the star is violently ripped apart by the black hole’s gravitational tidal forces — similar to how the Moon pulls tides on Earth but with greater strength. Then, pieces of the star are captured into a swiftly spinning disk orbiting the black hole. Finally, the black hole consumes what remains of the doomed star in the disk. This is what astronomers call a tidal disruption event (TDE).

But in some extremely rare cases, the supermassive black ho...

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Astronomers see Stellar Self-Control in action

Composite image of RCW 36.
Credits: X-ray: NASA/CXC/Ames Research Center/L. Bonne et al.; Infrared: ESA/NASA.JPL-Caltech/Herschel Space Observatory/JPL/IPAC

Many factors can limit the size of a group, including external ones that members have no control over. Astronomers have found that groups of stars in certain environments, however, can regulate themselves.

A new study has revealed stars in a cluster having “self-control,” meaning that they allow only a limited number of stars to grow before the biggest and brightest members expel most of the gas from the system. This process should drastically slow down the birth of new stars, which would better align with astronomers’ predictions for how quickly stars form in clusters. A paper describing these results appeared in the Aug...

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Hubble Glimpses a Glittering Gathering of Stars

This glittering gathering of stars is Pismis 26, a globular star cluster located about 23,000 light-years away. Many thousands of stars gleam brightly against the black backdrop of the image, with some brighter red and blue stars located along the outskirts of the cluster. The Armenian astronomer Paris Pismis first discovered the cluster in 1959 at the Tonantzintla Observatory in Mexico, granting it the dual name Tonantzintla 2.

Pismis 26 is located in the constellation Scorpius near the galactic bulge, which is an area near the center of our galaxy that holds a dense, spheroidal grouping of stars that surrounds a black hole...

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Non-detection of Key Signal allows Astronomers to Determine what the First Galaxies were – and weren’t – like

Observations by the NASA/ESA Hubble Space Telescope have taken advantage of gravitational lensing to reveal the largest sample of the faintest and earliest known galaxies in the universe.
Early galaxies capture by the NASA/ESA Hubble Telescope
Credit: NASA Goddard

Researchers have been able to make some key determinations about the first galaxies to exist, in one of the first astrophysical studies of the period in the early Universe when the first stars and galaxies formed, known as the cosmic dawn.

Using data from India’s SARAS3 radio telescope, researchers led by the University of Cambridge were able to look at the very early Universe — just 200 million years after the Big Bang — and place limits on the mass and energy output of the first stars and galaxies.

Counterintuitively, the researchers were able to place these limits on the earliest galaxies by not finding the signal they had been looking for, known as the 21-centimetre hydrogen line.

This non-detectio...

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