Astronomy Archives

July 31, 2020July 31, 2020 by Matt Williams

There are Natural Starshades Out There, Which Would Help Astronomers Image Exoplanets

TOI 1338 b is a circumbinary planet orbiting its two stars. It was discovered by TESS. Image Credit: NASA's Goddard Space Flight Center/Chris Smith

In the past few decades, the study of extrasolar planets has grown by leaps and bounds, with the confirmation of over 4000 exoplanets. With so many planets available for study, the focus of exoplanet-researchers is shifting from discovery to characterization. In the coming years, new technologies and next-generation telescopes will also enable Direct Imaging studies, which will vastly improve our understanding of exoplanet atmospheres.

To facilitate this process, astronomers will rely on costly technologies like coronagraphs and starshades, which block out the light of a star so any planets orbiting it will become more visible. However, according to a new study by an international team of astronomers and cosmologists, eclipsing binary stars could provide all the shading that’s needed to directly image planets orbiting them.

July 31, 2020July 30, 2020 by Paul M. Sutter

Supermassive black holes can cloak themselves in a cocoon of dust, making them invisible even when they should be bright quasars

Artist's impression of a shroud of dust cloaking a supermassive black hole, alongside the X-ray view of where black holes should be. Image credit: X-ray: NASA/CXC/Penn State/B.Luo et al; Illustration: NASA/CXC/M. Weiss

Quasars are the most powerful sources of light in the universe, but sometimes they’re hard to find. A team of astronomers used the Chandra X-ray Space Telescope to find some diamonds in the rough.

July 30, 2020July 30, 2020 by Paul M. Sutter

There’s a flash of ultraviolet just as a white dwarf is exploding 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

Astronomers recently spotted a rare type of supernova explosion that was accompanied by a massive flare of ultraviolet radiation. Untangling the mystery of the UV flash could help unravel the mysterious nature of these supernova explosions, and even help us understand the age of the universe.

July 28, 2020July 28, 2020 by Andy Tomaswick

Saturn-sized Planet Found in the Habitable Zone of Another Star. The First Planet Completely Discovered by Amateur Astronomers

Exoplanets have been a particularly hot topic of late. More than 4000 of them have been discovered since the first in 1995. Now one more can potentially be added to the list. This one is orbiting Gliese 3470, a red dwarf star located in the constellation Cancer. What makes this discovery particularly interesting is that this planet wasn’t discovered by any professional astronomers using high tech equipment like the Kepler Space Telescope. It was found entirely by amateurs.

July 27, 2020July 27, 2020 by Matt Williams

According to Globular Clusters, the Universe is 13.35 Billion Years Old

This dazzling image shows the globular cluster Messier 69, or M 69 for short, as viewed through the NASA/ESA Hubble Space Telescope. Globular clusters are dense collections of old stars. In this picture, foreground stars look big and golden when set against the backdrop of the thousands of white, silvery stars that make up M 69. Another aspect of M 69 lends itself to the bejewelled metaphor: As globular clusters go, M 69 is one of the most metal-rich on record. In astronomy, the term “metal” has a specialised meaning: it refers to any element heavier than the two most common elements in our Universe, hydrogen and helium. The nuclear fusion that powers stars created all of the metallic elements in nature, from the calcium in our bones to the carbon in diamonds. Successive generations of stars have built up the metallic abundances we see today. Because the stars in globular clusters are ancient, their metallic abundances are much lower than more recently formed stars, such as the Sun. Studying the makeup of stars in globular clusters like M 69 has helped astronomers trace back the evolution of the cosmos. M 69 is located 29 700 light-years away in the constellation Sagittarius (the Archer). The famed French comet hunter Charles Messier added M 69 to his catalogue in 1780. It is also known as NGC 6637. The image is a combination of exposures taken in visible and near-infrared light by Hubble’s Advanced Camera for Surveys, and covers a field of view of approximately 3.4 by 3.4 arcminutes.

It is a widely-accepted theory today that when the first stars formed in our Universe (ca. over 13 billion years ago), they quickly came together to form globular clusters. These clusters then coalesced to others to form the first galaxies, which have been growing through mergers and evolving ever since. For this reason, astronomers have long-suspected that the oldest stars in the Universe are to be found in globular clusters.

The study of stars in these clusters is therefore a means of determining the age of the Universe, which is still subject to some guesswork. In this vein, an international team of astronomers and cosmologists recently conducted a study of globular clusters in order to infer the age of the Universe. Their results indicate that the Universe is about 13.35 billion years old, a result that could help astronomers learn more about the expansion of the cosmos.

July 27, 2020July 28, 2020 by Brian Koberlein

Gamma-Ray Telescopes Can Measure the Diameters of Other Stars

The VERITAS array, an air Cherenkov telescope designed to detect low-energy cosmic rays. Credit: VERITAS

In astronomy, the sharpness of your image depends upon the size of your telescope. When Galileo and others began to view the heavens with telescopes centuries ago, it changed our understanding of the cosmos. Objects such as planets, seen as points of light with the naked eye, could now be seen as orbs with surface features. But even under these early telescopes, stars still appeared as a point of light. While Galileo could see Jupiter or Saturn’s size, he had no way to know the size of a star.

July 26, 2020July 26, 2020 by Andy Tomaswick

The Moons of Uranus Are Fascinating Enough On Their Own That We Should Send a Flagship Mission Out There

What’s the most interesting fact you know about Uranus? The fact that its rotational axis is completely out of line with every other planet in the solar system? Or the fact that Uranus’ magnetosphere is asymmetrical, notably tilted relative to its rotational axis, and significantly offset from the center of the planet? Or the fact that it’s moons are all named after characters from Shakespeare or Alexander Pope?

All of those facts (with the exception of the literary references) have come from a very limited dataset. Some of the best data was collected during a Voyager 2 flyby in 1986. Since then, the only new data has come from Earth-based telescopes. While they’ve been steadily increasing in resolution, they have only been able to scratch the surface of what may be lurking in the system surrounding the closest Ice Giant. Hopefully that is about to change, as a team of scientists has published a white paper advocating for a visit from a new Flagship class spacecraft.

July 24, 2020July 24, 2020 by Matt Williams

The Moon is an Ideal Spot for a Gravitational Wave Observatory

High-resolution view of the lunar surface (JAXA/SELENE)

In the coming years, multiple space agencies will be sending missions (including astronauts) to the Moon’s southern polar region to conduct vital research. In addition to scouting resources in the area (in preparation for the construction of a lunar base) these missions will also investigate the possibility of conducting various scientific investigations on the far side of the Moon.

However, two prominent scientists (Dr. Karan Jani and Prof. Abraham Loeb) recently published a paper where they argue that another kind of astronomy could be conducted on the far side of the Moon – Gravitational Wave astronomy! As part of NASA’s Project Artemis, they explain how a Gravitational-wave Lunar Observatory for Cosmology (GLOC) would be ideal for exploring GW in the richest and most challenging frequencies.

July 23, 2020July 23, 2020 by Evan Gough

Wow! An Actual Picture of Multiple Planets Orbiting a Sunlike Star

This image, captured by the SPHERE instrument on ESO’s Very Large Telescope, shows the star TYC 8998-760-1 accompanied by two giant exoplanets. This is the first time astronomers have directly observed more than one planet orbiting a star similar to the Sun. The image was captured by blocking the light from the young, Sun-like star (on the top left corner) using a coronagraph, which allows for the fainter planets to be detected. The bright and dark rings we see on the star’s image are optical artefacts. The two planets are visible as two bright dots in the centre and bottom right of the frame. Image Credit: ESO/Bohn et al, 2020

We’ve detected thousands of exoplanets, but for the most part, nobody’s ever seen them. They’re really just data, and graphs of light curves. The exoplanet images you see here at Universe Today and other space websites are the creations of very skilled illustrators, equal parts data and creative license. But that’s starting to change.

The European Southern Observatory’s Very Large Telescope (VLT) has captured images of two exoplanets orbiting a young, Sun-like star.

July 23, 2020July 23, 2020 by Evan Gough

Astronomers are Starting to Find Planets in Much Longer Orbits. Cooler, More Habitable Planets

This artist’s view shows the planet orbiting the young star Beta Pictoris. This exoplanet is the first to have its rotation rate measured. Its eight-hour day corresponds to an equatorial rotation speed of 100 000 kilometres/hour — much faster than any planet in the Solar System.

We’re getting better and better at detecting exoplanets. Using the transit method of detection, the Kepler Space Telescope examined over 530,000 stars and discovered over 2,600 explanets in nine years. TESS, the successor to Kepler, is still active, and has so far identified over 1800 candidate exoplanets, with 46 confirmed.

But what if, hidden in all that data, there were even more planets? Astronomers at Warwick University said they’ve found one of these “lost” planets, and that they think they’ll find even more.