Sagittarius A* (short for “Sagittarius A-Star”) is a brilliant and compact astronomical radio source located at the Milky Way’s Galactic Center. It’s at the Sagittarius-Scorpius border, around 5.6 degrees south of the ecliptic, and visually close to the Butterfly Cluster (M6) and Shaula. A supermassive black hole, akin to huge structures at the centers of most, if not all, spiral and elliptical galaxies, can be found in Sagittarius A*.
Observations of numerous stars around Sagittarius A*, particularly star S2, were utilized to calculate the object’s mass and radius upper bounds. Astronomers have determined that Sagittarius A* is the Milky Way’s center supermassive black hole based on mass and increasingly accurate radius limitations. Its mass is currently estimated to be somewhat more than 4 million solar masses.
The Nobel Prize in Physics was awarded to Reinhard Genzel and Andrea Ghez in 2020 for discovering that Sgr A* is a supermassive compact object for which a black hole is the only currently known explanation.
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What type of black hole is Sagittarius A?
The Milky Way Galaxy’s compact and energetic source, known as Sagittarius A*, is located in the galaxy’s center. Sagittarius A* is a supermassive black hole in the constellation Sagittarius, with a mass of 4,310,000 Suns.
Why is it called Sagittarius A?
The designation ‘Sagittarius A*’ refers to where the supermassive black hole in the center of our galaxy is thought to be located. To distinguish this spot within the enormous expanse of sky that this constellation spans, astronomers named it ‘Sagittarius A.’
What is known about Sagittarius A?
It is a powerful radio source that is part of the larger Sagittarius A complex. The synchrotron process is responsible for the majority of the radio radiation, suggesting the presence of free electrons and magnetic fields. Sagittarius A* is a small, brilliant point source in the constellation Sagittarius.
How do we know that Sagittarius A is a black hole?
A black hole is a region of space that is so densely packed with matter that nothing, not even a ray of light, can escape. Although we can’t see a black hole, we can observe the material that surrounds it with telescopes. The matter swirling around a black hole, which could be made up of gas or dust, warms up and produces detectable radiation. Telescopes can sometimes detect a black hole’s gravitational influence on the motions of nearby individual stars.
Although a point-like radio source known as Sagittarius A* (pronounced Sagittarius A-star) was discovered in the 1970s at the heart of our Milky Way galaxy, researchers were unable to pinpoint enough of its properties to fully identify it. Astronomers began utilizing new techniques to measure the orbits of fast-moving stars around this area in the 1990s. By 2008, they had not only traced full orbits, but also gathered enough data to calculate the mass of the stars and their distances from them. They could confirm at this stage that the mass of the object at the center of those orbits is 4.6 million times that of our sun, and that its size is no larger than Pluto’s orbit. It could only be a gigantic black hole if that was the case. Researchers are still keeping an eye on these stars, but for a different reason: to test fundamental physics, such as Einstein’s general theory of relativity, which is still valid.
What is Sagittarius A * made of?
From the perspective of the Earth, Sgr A West appears to be a three-arm spiral. It’s also known as the “Minispiral” because of this. The Minispiral’s appearance and nickname are deceiving, as its three-dimensional structure is not that of a spiral. It is made up of multiple dust and gas clouds that circle and fall at speeds of up to 1,000 kilometers per second onto Sagittarius A*. These clouds have an ionized surface layer. The population of big stars (about one hundred OB stars have been detected so far) that likewise inhabit the core parsec is the source of ionisation.
The Circumnuclear Disk, which surrounds Sgr A West, is a vast, clumpy torus of colder molecular gas (CND). The form and kinematics of Sgr A West’s Northern Arm cloud indicate that it was once a clump in the CND that dropped due to some perturbation, maybe the supernova explosion that caused Sgr A East. The Northern Arm appears as a bright North–South emission ridge, although it extends far to the East and can be seen as a dim extended source.
The ionized inner surface of the CND is interpreted as the Western Arc (outside the field of view of the figure displayed on the right). Although they do not share the same orbital plane as the Northern Arm, the Eastern Arm and the Bar appear to be two more huge clouds. They are thought to be worth around 20 solar masses each.
Many tiny cloudlets and holes inside the giant clouds may be observed on top of these massive scale formations (of the order of a few light-years in size). The Minicavity, which is regarded as a bubble blown inside the Northern Arm by the stellar wind of a massive star that has yet to be found, is the most visible of these perturbations.
Is Sagittarius A The biggest black hole?
The list of (normal) gravitational suspects starts with black holes that are just the size of protons but have the mass of a large mountain. The comparison then ascends through black holes the size of the one that keeps V723 Mon in orbit, a star 24 times the mass of the Sun. However, as the narrator of the channel points out, that black hole is barely 17.2 kilometers (approximately 10 miles) across.
The comparison then progresses to black holes with hundreds of times the mass of the Sun. These appear to be enormous until the film progresses to black holes millions of times larger than the Sun. Sagittarius A*, the supermassive black hole at the center of the Milky Way Galaxy, is one of these monsters, although having a radius just 17 times that of the Sun.
The film concludes with an examination of ultramassive black holes, which follow the supermassive black holes. That is, after all, a technical term. Ultramassive black holes are “perhaps the largest single bodies that will ever exist,” putting all other black holes to shame. The mass of these huge physical manifestations is billions of times that of the Sun. They have the capacity to house several solar systems. With the very end of the video, Ton 618, the greatest ultramassive black hole, appears, which, at 66 billion times the mass of the Sun, will have a significant impact on how we daydream about the cosmos in the future.
Is Sagittarius A growing?
And such expansion can be enormous. According to experts, the black hole at the center of the famed Sombrero Galaxy, also known as M104 or NGC 4594, has absorbed the equivalent of one sun every 20 years and now has at least 500 million solar masses.
According to experts, the supermassive black hole at the center of the Milky Way Galaxy appears to be significantly less voracious, growing at a rate of one solar mass every 3,000 years. This black hole, also known as Sagittarius A* (pronounced “Sagittarius A-star”), has a mass of around 4 million suns, according to scientists.
How fast is Sagittarius A * spinning?
Using the durations of QPOs corresponding to K, we can now calculate the spin parameter of black holes. Sgr A*, for example, has a period of 31.4 minutes, while Galactic X-ray sources have periods of lower HF-QPOs. The frequency of single peak HF-QPOs is denoted by the letter K. The estimated mass of a supermassive black hole in Sgr A* is taken from recent studies to constrain the consequent spin parameter (