Astronomy Jargon 101: Globular Clusters

The NASA/ESA Hubble Space Telescope offers this delightful view of the crowded stellar encampment called Messier 68, a spherical, star-filled region of space known as a globular cluster. Mutual gravitational attraction amongst a cluster’s hundreds of thousands or even millions of stars keeps stellar members in check, allowing globular clusters to hang together for many billions of years. Astronomers can measure the ages of globular clusters by looking at the light of their constituent stars. The chemical elements leave signatures in this light, and the starlight reveals that globular clusters' stars typically contain fewer heavy elements, such as carbon, oxygen and iron, than stars like the Sun. Since successive generations of stars gradually create these elements through nuclear fusion, stars having fewer of them are relics of earlier epochs in the Universe. Indeed, the stars in globular clusters rank among the oldest on record, dating back more than 10 billion years. More than 150 of these objects surround our Milky Way galaxy. On a galactic scale, globular clusters are indeed not all that big. In Messier 68's case, its constituent stars span a volume of space with a diameter of little more than a hundred light-years. The disc of the Milky Way, on the other hand, extends over some 100 000 light-years or more. Messier 68 is located about 33 000 light-years from Earth in the constellation Hydra (The Female Water Snake). French astronomer Charles Messier notched the object as the sixty-eighth entry in his famous catalogue in 1780. Hubble added Messier 68 to its own impressive list of cosmic targets in this image using the Wide Field Camera of Hubble’s Advanced Camera for Surveys. The image, which combines visible and infrared light, has a field of view of approximately 3.4 by 3.4 arcminutes. Credit: Hubble/NASA/ESA

In this series we are exploring the weird and wonderful world of astronomy jargon! You’ll feel a little old and red with today’s topic: globular clusters!

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Exoplanet Found With a Highly Eccentric Orbit

An artist's rendering of TOI-1231 b, a Neptune-like planet about 90 light years away from Earth. Credit: NASA/JPL-Caltech

The study of extrasolar planets has revealed some interesting things in recent decades. Not only have astronomers discovered entirely new types of planets – Super Jupiters, Hot Jupiters, Super-Earths, Mini-Neptunes, etc. – it has also revealed new things about solar system architecture and planetary dynamics. For example, astronomers have seen multiple systems of planets where the orbits of the planets did not conform to our Solar System.

According to a new study led by the University of Bern, an international team of researchers recently observed a Mini-Neptune (TOI-2257 b) orbiting a red dwarf star located about 188.5 light-years from Earth. What was interesting about this find was how the small ice giant had such an eccentric orbit, which is almost twice as long as it is wide! This is almost two and a half times as eccentric as Mercury, making TOI-2257 b the most eccentric planet ever discovered!

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Fast Radio Bursts can now be Tracked in Real-Time

The CHIME cylindrical parabolic radio telescope near Penticton, BC. Credit: CHIME/DRAO/NRC

Located in the Okanagan Valley outside of Penticton, British Columbia, there is a massive radio observatory dedicated to observing cosmic radio phenomena. It’s called the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a cylindrical parabolic radio telescope that looks like what snowboarders would call a “half-pipe.” This array is part of the Dominion Radio Astrophysical Observatory (DRAO), overseen by the National Research Council (NRC).

Originally, the observatory was meant to detect radio waves from neutral hydrogen gas in the early Universe. Today, it is used for other objectives, such as detecting and studying Fast Radio Bursts (FRBs). Since it became operational, CHIME scientists have been busy sorting through terabytes of data to pinpoint signals, often finding several in a single day. To assist with all this data-mining and coordinate CHIMEs efforts with other facilities worldwide, scientists from McGill University have developed a new system for sharing the enormous amount of data CHIME generates.

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Astronomers Watch a Star Die and Then Explode as a Supernova

Artist's impression of a supernova. Supernovae bombarded Earth with radiation that has implications for the development of life on Earth. Image Credit: NASA

It’s another first for astronomy.

For the first time, a team of astronomers have imaged in real-time as a red supergiant star reached the end of its life. They watched as the star convulsed in its death throes before finally exploding as a supernova.

And their observations contradict previous thinking into how red supergiants behave before they blow up.

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Astronomy Jargon 101: Kirkwood Gaps

This image depicts the two areas where most of the asteroids in the Solar System are found: the asteroid belt between Mars and Jupiter, and the trojans, two groups of asteroids moving ahead of and following Jupiter in its orbit around the Sun. The binary asteroid 288P is part of the asteroid belt.

In this series we are exploring the weird and wonderful world of astronomy jargon! You’ll have to mind the space between the platform and the car in today’s topic: Kirkwood gaps!

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Rings in the Early Solar System Kept our Planet From Becoming a Super-Earth

A protosolar disk is the disk of material around a young stellar object that isn't yet a star. It's called a protoplanetary disk once the star has formed and begun fusion. Planetesimals are the building blocks of planets and are present in both stages of a disk's evolution. Image Credit: NASA/JPL

To date, a total of 4,884 extrasolar planets have been confirmed in 3,659 systems, with another 8,414 additional candidates awaiting confirmation. In the course of studying these new worlds, astronomers have noted something very interesting about the “rocky” planets. Since Earth is rocky and the only known planet where life can exist, astronomers are naturally curious about this particular type of planet. Interestingly, most of the rocky planets discovered so far have been many times the size and mass of Earth.

Of the 1,702 rocky planets confirmed to date, the majority (1,516) have been “Super-Earths,” while only 186 have been similar in size and mass to Earth. This raises the question: is Earth an outlier, or do we not have enough data yet to determine how common “Earth-like” planets are. According to new research by an international team led by Rice University, it may all have to do with protoplanetary rings of dust and gas in an early solar system.

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What is the Arecibo Message?

A team of astronomers from UCLA searched for "technosignatures" in the Kepler field data. Credit and Copyright: Danielle Futselaar

On November 16th, 1974, a coded radio message was broadcast from the Arecibo Observatory in Puerto Rico. The message contained information on mathematics, humanity, the Solar System, DNA, and the Observatory itself. The destination for this message was Messier 13 (NGC 6205 or “The Great Hercules Cluster”), a globular star cluster located about 25,000 light-years from Earth in the constellation of Hercules.

This historic signal was the Arecibo Message, humanity’s first attempt at Messaging Extraterrestrial Intelligence (METI). Almost fifty years later, the Message remains a focal point in the Search for Extraterrestrial Intelligence (SETI), the ethics of messaging, and why we haven’t heard from any extraterrestrial civilization (the Fermi Paradox). What’s more, a growing movement today would like to see more METI efforts mounted in the future.

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