How Do Stars Get Kicked Out of Globular Clusters?

Hubble image of Messier 54, a globular cluster located in the Sagittarius Dwarf Galaxy. Credit: ESA/Hubble & NASA

Globular clusters are densely-packed collections of stars bound together gravitationally in roughly-shaped spheres. They contain hundreds of thousands of stars. Some might contain millions of stars.

Sometimes globular clusters (GCs) kick stars out of their gravitational group. How does that work?

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Astronomers Find a Sun-like Star Orbiting a Nearby Black Hole

Gaia BH1 is a Sun-like star co-orbiting with a black hole estimated at 10 times the Sun's mass. Credit: ESO/L. Calcada

In 1916, Karl Schwarzchild theorized the existence of black holes as a resolution to Einstein’s field equations for his Theory of General Relativity. By the mid-20th century, astronomers began detecting black holes for the first time using indirect methods, which consisted of observing their effects on surrounding objects and space. Since the 1980s, scientists have studied supermassive black holes (SMBHs), which reside at the center of most massive galaxies in the Universe. And by April 2019, the Event Horizon Telescope (EHT) collaboration released the first image ever taken of an SMBH.

These observations are an opportunity to test the laws of physics under the most extreme conditions and offer insights into the forces that shaped the Universe. According to a recent study, an international research team relied on data from the ESA’s Gaia Observatory to observe a Sun-like star with strange orbital characteristics. Due to the nature of its orbit, the team concluded that it must be part of a black hole binary system. This makes it the nearest black hole to our Solar System and implies the existence of a sizable population of dormant black holes in our galaxy.

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Gaia's Massive Third Data Release is out!

It’s here! The third and largest data release (DR3) from the ESA’s Gaia Observatory has officially been made public. As promised, the DR3 contains new and improved details for almost two billion stars in our galaxy, including the chemical compositions, temperatures, colors, masses, ages, and the velocities at which stars move. The release coincided with a virtual press event hosted by the Gaia Data Processing and Analysis Consortium (DPAC) on June 13th, which featured ESA officials and guest speakers who addressed the significance of the new data.

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ESA is About to Release its Third Giant Data Release From Gaia

The European Space Agency’s (ESA) Gaia Observatory is a mission dedicated to astrometry, a branch of astronomy where the velocity and proper motion of celestial objects are measured to learn more about the formation and evolution of the cosmos. For the past eight and a half years, this space-based has been studying over two billion objects in the Universe. This includes stars in the Milky Way but also planets, comets, asteroids, and distant galaxies. This information obtained by this mission will be used to create the most-detailed 3D catalog of the Milky Way ever.

Since the mission began in 2013, two major catalogs have been released, known as Gaia Data Release 1 and 2 (DR1 and DR2), accompanied by a smaller data set – Early Data Release 3 (EDR3). On June 13th, Gaia’s third full catalog (DR3) will be released, containing new and improved details for the two billion celestial objects it has been observing. The release will coincide with a virtual press event hosted by the Gaia Data Processing and Analysis Consortium (DPAC), where featured speakers will share the significance of this latest release and how it revolutionizes our understanding of the galaxy.

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Gaia is an Even More Powerful Planet Hunter Than we Thought

Utilizing tools for purposes they weren’t initially intended for is a strength of the astronomical community. Scrounging through data collected for one purpose and looking for hints of another seems to be a favorite pastime of many a professional astronomer. That tradition is alive and well, with a team reanalyzing the first few data sets from Gaia, ESA’s star cataloging explorer. They found hints of exoplanets, and it turns out the probe launched in 2013 is a much better planet hunter than initially thought.

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Thanks to Gaia, Astronomers are Able to Map Out Nebulae in 3D

In this image of nebulae in the Orion Molecular Complex, the submillimetre-wavelength glow of dust clouds is overlaid on a view of the region in the more familiar visible light, from the Digitized Sky Survey 2. The large orange bar extended down to the lower left is the Orion A portion of the Complex. The large bright cloud in the upper right of the image is the well-known Orion Nebula, also called Messier 42.  (Credit: ESO/Digitized Sky Survey 2.) Now astronomers have a new tool to understand nebulae like this one: 3D mapping using Gaia data.
In this 2D image of nebulae in the Orion Molecular Complex, the submillimetre-wavelength glow of dust clouds is overlaid on a visible-light view of the region. The large orange bar extended down to the lower left is the Orion A portion of the Complex. The large bright cloud in the upper right is the well-known Orion Nebula, also called Messier 42. (Credit: ESO/Digitized Sky Survey 2.) Now astronomers have a new tool to understand nebulae like this one: 3D mapping using Gaia data.

Ever wonder what it would be like to fly through the Orion Nebula with all its newborn stars? Or buzz through the California Nebula? Of course, we’ve seen simulated “fly-throughs” of nebulae in sci-fi TV and movies and on planetarium domes. But, what if we had a warp-speed spaceship and could chart a path through the real thing? The first thing we’d need is accurate data about that region of space. That’s where a 3D model with precise distance measurements to stars and other objects would come in really handy.

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ESA’s Gaia Just Took a Picture of L2 Neighbor JWST

Gaia snaps photo of Webb. Credit: ESA

Oh, hello there new neighbor!  In February, the Gaia spacecraft took a picture of its new closest companion in space at the second Lagrangian point, the James Webb Space Telescope.

Gaia is an optical telescope that is mapping out our galaxy by surveying the motions of more than a thousand million stars. Astronomers for the mission realized that once JWST reached L2, it would be in Gaia’s field of view.  It spied JWST when the two spacecraft were a million km apart.

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Our Part of the Galaxy is Packed with Binary Stars

Binary star systems are everywhere. They make up a huge percentage of all known solar systems: from what we can tell, about half of all Sun-like stars have a binary partner. But we haven’t really had a chance to study them in detail yet. That’s about to change. Using data from the European Space Agency’s Gaia spacecraft, a research team has just compiled a gigantic new catalog of nearby binary star systems, and it shows that at least 1.3 million of them exist within 3000 light-years of Earth.

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Gaia has Already Given Us 5 New Insights Into the Milky Way

The ESA's Gaia mission is currently on a five-year mission to map the stars of the Milky Way. Gaia has found evidence for a galactic collision that occurred between 300 million and 900 million years ago. Image credit: ESA/ATG medialab; background: ESO/S. Brunier.
The ESA's Gaia mission is currently on a five-year mission to map the stars of the Milky Way. Gaia has found evidence for a galactic collision that occurred between 300 million and 900 million years ago. Image credit: ESA/ATG medialab; background: ESO/S. Brunier.

The European Space Agency launched the Gaia mission in 2013. The mission’s overall goal was to discover the history of the Milky Way by mapping out the positions and velocities of one billion stars. The result is kind of like a movie that shows the past and the future of our galaxy.

The mission has released two separate, massive data sets for researchers to work through, with a third data release expected soon. All that data has spawned a stream of studies into our home galaxy.

Recently, the ESA drew attention to five new insights into the Milky Way galaxy. Allof these discoveries directly stemmed from the Gaia spacecraft.

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A Stellar Stream of Stars, Stolen from Another Galaxy

The all-sky view that the Gaia survey would have of a simulated Milky-Way-like galaxy. [Credit: Sanderson et al. The Astrophysical Journal, January 6, 2020, DOI: 10.3847/1538-4365/ab5b9d]

Modern professional astronomers aren’t much like astronomers of old. They don’t spend every suitable evening with their eyes glued to a telescope’s eyepiece. You might be more likely to find them in front of a super-computer, working with AI and deep learning methods.

One group of researchers employed those methods to find a whole new collection of stars in the Milky Way; a group of stars which weren’t born here.

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