A Tadpole-Shaped Cloud of Gas is Whirling Around a Black Hole

Artist’s Impression of the “Tadpole” Molecular Cloud and the black hole at the gravitational center of its orbit. Credit: Keio University

In the 1930s, astrophysicists theorized that at the end of their life cycle, particularly massive stars would collapse, leaving behind remnants of infinite mass and density. As a proposed resolution to Einstein’s field equations (for his Theory of General Relativity), these objects came to be known as “black holes” because nothing (even light) could escape them. By the 1960s, astronomers began to infer the existence of these objects based on the observable effects they have on neighboring objects and their surrounding environment.

Despite improvements in instruments and interferometry (which led to the first images of M87 and Sagittarius A*), the study of black holes still relies on indirect methods. In a recent study, a team of Japanese researchers identified an unusual cloud of gas that appears to have been elongated by a massive, compact object that it orbits. Since there are no massive stars in its vicinity, they theorize that the cloud (nicknamed the “Tadpole” because of its shape) orbits a black hole roughly 27,000 light-years away in the constellation Sagittarius.

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A Very Young Star is Forming Near the Milky Way's Supermassive Black Hole

Artist's impression of a young, massive star orbiting Sagittarius A*. Credit: University of Cologne

Since the 1930s, physicists and radio engineer Karl Jansky reported discovering a persistent radio source coming from the center of our galaxy. This source came to be known as Sagittarius A* (Sgr A*), and by the 1970s, astronomers determined that it was a supermassive black hole (SMBH) roughly four million times the mass of our Sun. Since then, astronomers have used increasingly-advanced radio telescopes to study Sgr A* and its surrounding environment. This has led to many exotic discoveries, such as the many “Stars stars” and gaseous “G objects” that orbit it.

The study of these objects and how the powerful gravity of Sgr A* has allowed scientists to test the laws of physics under the most extreme conditions. In a recent study, an international team of researchers led by the University of Cologne made a startling discovery. Based on data collected by multiple observatories, they observed what appears to be a newly-formed star (X3a) in the vicinity of Sgr A*. This discovery raises significant questions about how young stellar objects (YSOs) can form and survive so close to an SMBH, where they should be torn apart by violent gravitational forces.

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Machine Learning is a Powerful Tool When Searching for Exoplanets

Three young planets in orbit around an infant star known as HD 163296 Credit: NRAO/AUI/NSF; S. Dagnello

Astronomy has entered the era of big data, where astronomers find themselves inundated with information thanks to cutting-edge instruments and data-sharing techniques. Facilities like the Vera Rubin Observatory (VRO) are collecting about 20 terabytes (TB) of data on a daily basis. Others, like the Thirty-Meter Telescope (TMT), are expected to gather up to 90 TB once operational. As a result, astronomers are dealing with 100 to 200 Petabytes of data every year, and astronomy is expected to reach the “exabyte era” before long.

In response, observatories have been crowdsourcing solutions and making their data open-access so citizen scientists can assist with the time-consuming analysis process. In addition, astronomers have been increasingly turning to machine learning algorithms to help them identify objects of interest (OI) in the Universe. In a recent study, a team led by the University of Georgia revealed how artificial intelligence could distinguish between false positives and exoplanet candidates simultaneously, making the job of exoplanet hunters that much easier.

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Quasars Produce Giant Jets That Focus Like Lasers. Why They Focus is Still a Mystery, but it’s not Coming From the Galaxy Itself

New technologies bring new astronomical insights, which is especially satisfying when they help answer debates that have been ongoing for decades. One of those debates is why exactly the plasma emitted from pulsars “collimates” or is brought together in a narrow beam. While it doesn’t provide a definitive answer to that question, a new paper from an international group of scientists points to a potential solution, but it will require even more advanced technologies.

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A new way to Discover Planets? Astronomers Detect an Exoplanet by Seeing its Trojan Belts

Artist view of a planet and protoplanetary disk around a young star. Credit: M.Weiss/Center for Astrophysics | Harvard & Smithsonian

Although we have found thousands of exoplanets in recent years, we really only have three methods of finding them. The first is to observe a star dimming slightly as a planet passes in front of it (transit method). The second is to measure the wobble of a star as an orbiting planet gives it a gravitational tug (Doppler method). The third is to observe the exoplanet directly. Now a new study in the Astrophysical Journal Letters has a fourth method.

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Once Again, Galaxies Look Surprisingly Mature Shortly After the Beginning of the Universe

A young galaxy with the catchy, roll-off-the-tongue name A1689-zD1 has experts in galactic formation talking. Recent observations show that this galaxy, seen as it would have looked just 700 million years after the Big Bang, is larger than initially believed, with significant outflows of hot gas from its core, and a halo of cold gas emanating from its outer rim. A1689-zD1 is considered representative of young ‘normal’ galaxies (as opposed to ‘massive’ galaxies), and the new observations suggest that the adolescence of normal galaxies may be more rambunctious than previous models suggest.

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Dying Star Puffs out six Smoke Rings

Artist view of V Hya in its death throes. Credit: ALMA (ESO/NAOJ/NRAO)/S. Dagnello (NRAO/AUI/NSF)

Our Sun’s days are numbered. In about 5 billion years the Sun will expand into a red giant, casting off its outer layers before settling down to become a white dwarf. It’s the inevitable fate of most sunlike stars, and the process is well understood. But as a recent study shows, there are still a few things we have to learn about dying Suns.

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Astronomers See Carbon-Rich Nebulae Where Planets are Forming

The protoplanetary disk

Understanding the birth of a planet is a challenging puzzle. We know that planets form inside clouds of gas and dust that surround new stars, known as protoplanetary disks. But grasping exactly how that process works – connecting the dots between a dust cloud and a finished planet – is not easy. An international team of astronomers is attempting to unlock some of those secrets, and have recently completed the most extensive chemical composition mapping of several protoplanetary discs around five young stars. Their research allows them to begin to piece together the chemical makeup of future exoplanets, offering a glimpse into the formation of new alien worlds.

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ALMA’s new Receivers Will let it see Longer Wavelengths, Peering Closer to the Beginning of the Universe

ALMA is an array of dishes located at the Atacama Desert in Chile. Image: ALMA (ESO/NAOJ/NRAO), O. Dessibourg

The ALMA telescope is getting a new set of receivers, enabling it to detect wavelengths down to 8.5 mm. These wavelengths are crucial for observations of the transformative epoch of reionization, when the first stars to appear in the universe unleashed a fury of radiation.

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The Galactic Beauty of Star Formation

Image of Galaxy NGC 3627 located in the constellation LEO. The golden gas glow corresponds to clouds of ionized hydrogen, while the bluish regions reveal the distribution of slightly older stars. Credit: ESO/PHANGS

I’d never seen galaxy images like this before. Nobody had! These images highlight star forming regions in nearby(ish) galaxies. There are still a number of unanswered questions surrounding how star formation actually occurs. To answer those questions, we are observing galaxies that are actively forming stars within giant clouds of gas. Until recently, we didn’t have the resolution needed to clearly image the individual gas clouds themselves. But images released by a project called PHANGS (Physics at High Angular resolution in Nearby GalaxieS) in a collaboration between the European Southern Observatory Very Large Telescope and the Atacama Large millimeter/submillmeter Array (ALMA) have provided never before seen detail of star forming clouds in other galaxies.

This image combines observations of the nearby galaxies NGC 1300, NGC 1087, NGC 3627 (top, from left to right), NGC 4254 and NGC 4303 (bottom, from left to right) taken with the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s Very Large Telescope (VLT). Each individual image is a combination of observations conducted at different wavelengths of light to map stellar populations and warm gas.. Image and Image Description PHANGS/ESO. Original Image
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