Astronomy Archives

June 30, 2022June 30, 2022 by Matt Williams

Tidal Heating Could Make Exomoons Much More Habitable (and Detectable)

An artist's illustration of the Kepler 1625 system. The star in the distance is called Kepler 1625. The gas giant is Kepler 1625B, and the exomoon orbiting it is unnamed. The moon is about as big as Neptune, but is a gas moon. Image: NASA, ESA, and L. Hustak (STScI)

Within the Solar System, most of our astrobiological research is aimed at Mars, which is considered to be the next-most habitable body beyond Earth. However, future efforts are aimed at exploring icy satellites in the outer Solar System that could also be habitable (like Europa, Enceladus, Titan, and more). This dichotomy between terrestrial (rocky) planets that orbit within their a system’s Habitable Zones (HZ) and icy moons that orbit farther from their parent stars is expected to inform future extrasolar planet surveys and astrobiology research.

In fact, some believe that exomoons may play a vital role in the habitability of exoplanets and could also be a good place to look for life beyond the Solar System. In a new study, a team of researchers investigated how the orbit of exomoons around their parent bodies could lead to (and place limits on) tidal heating – where gravitational interaction leads to geological activity and heating in the interior. This, in turn, could help exoplanet-hunters and astrobiologists determine which exomoons are more likely to be habitable.

June 30, 2022June 30, 2022 by Carolyn Collins Petersen

Red Supergiant Stars Bubble and Froth so Much That Their Position in the Sky Seems to Dance Around

This artist’s impression shows the red supergiant star. Using ESO’s Very Large Telescope Interferometer, an international team of astronomers have constructed the most detailed image ever of this, or any star other than the Sun. Credit: ESO/M. Kornmesser

Making a 3D map of our galaxy would be easier if some stars behaved long enough to get good distances to them. However, red supergiants are the frisky kids on the block when it comes to pinning down their exact locations. That’s because they appear to dance around, which makes pinpointing their place in space difficult. That wobble is a feature, not a bug of these massive old stars and scientists want to understand why.

So, as with other challenging objects in the galaxy, astronomers have turned to computer models to figure out why. In addition, they are using Gaia mission position measurements to get a handle on why red supergiants appear to dance.

Artist’s impression of the red supergiant star Betelgeuse as it was revealed with ESO’s Very Large Telescope. It shows a boiling surface and material shed by the star as it ages. Credit: ESO/L.Calçada

June 30, 2022June 30, 2022 by Evan Gough

This is How You Get Multiple Star Systems

G205.46-14.56 clump located in Orion molecular cloud complex. The yellow contours stand for the dense cores discovered by JCMT, and the zoomed-in pictures shows the 1.3mm continuum emission of ALMA observation. These observations give insight into the formation of various stellar systems in dense cores. Image Credit: Qiuyi Luo et al. 2022.

Stars form inside massive clouds of gas and dust called molecular clouds. The Nebular Hypothesis explains how that happens. According to that hypothesis, dense cores inside those clouds of hydrogen collapse due to instability and form stars. The Nebular Hypothesis is much more detailed than that short version, but that’s the basic idea.

The problem is that it only explains how single stars form. But about half of the Milky Way’s stars are binary pairs or multiple stars. The Nebular Hypothesis doesn’t clearly explain how those stars form.

June 29, 2022June 29, 2022 by Carolyn Collins Petersen

A Dying Star’s Last Act was to Destroy all Its Planets

Artist's rendition of a white dwarf from the surface of an orbiting exoplanet. Astronomers have found two giant planet candidates orbiting two white dwarfs. More proof that giant planets can surve their stars' red giant phases. Image Credit: Madden/Cornell University

When white dwarfs go wild, their planets suffer through the resulting chaos. The evidence shows up later in and around the dying star’s atmosphere after it gobbles up planetary and cometary debris. That’s the conclusion a team of UCLA astronomers came to after studying the nearby white dwarf G238-44 in great detail. They found a case of cosmic cannibalism at this dying star, which lies about 86 light-years from Earth.

If that star were in the place of our Sun, it would ingest the remains of planets, asteroids, and comets out to the Kuiper Belt. That expansive buffet makes this stellar cannibalism act one of the most widespread ever seen.

June 29, 2022June 29, 2022 by David Dickinson

Record ‘Fast Nova’ Flares Over a Single Day

A galactic nova flared briefly into naked eye visibility for a day, before vanishing from sight.

Some stars burn bright but brief. These transitory novae pepper the sky, with one flaring into naked eye visibility every few years… but it was a recent brief appearance of just such a ‘new star’ that gave astronomers a chance to probe the secrets of the Universe.

June 27, 2022June 27, 2022 by Matt Williams

We Could Discover new Kinds of Particles Around Black Holes Through Gravitational Waves

The Laser Interferometer Space Antenna (LISA) consists of three spacecraft orbiting the sun in a triangular configuration. The LISA mission will study the mergers of supermassive black holes, test Einstein's theory of general relativity, probe the early Universe, and search for gravitational waves. As these passing waves ripple space and time, they will alter the lasers shining between the spacecraft, offering a different perspective on the Universe. LISA is scheduled for launch in 2015. Credit: NASA

On February 11th, 2016, researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) announced the detection of gravitational waves (GW) for the first time. As predicted by Einstein’s General Theory of Relativity, these waves result from massive objects merging, which causes ripples through spacetime that can be detected. Since then, astrophysicists have theorized countless ways that GWs could be used to study physics beyond the standard models of gravity and particle physics and advance our understanding of the Universe.

To date, GWs have been proposed as a means of studying Dark Matter, the interiors of neutron stars and supernovae, mergers between supermassive black holes, and more. In a recent study, a team of physicists from the University of Amsterdam and Harvard University has proposed a way where GWs could be used to search for ultralight bosons around rotating black holes. This method could not only offer a new way to discern the properties of binary black holes but could lead to the discovery of new particles beyond the Standard Model.

June 26, 2022June 26, 2022 by Scott Alan Johnston

Remember That Rocket That was Going to Crash Into the Moon? Scientists Think They've Found the Crater

The Lunar Reconnaissance Orbiter (LRO) – NASA’s eye-in-the-sky in orbit around the Moon – has found the crash site of the mystery rocket booster that slammed into the far side of the Moon back on March 4th, 2022. The LRO images, taken May 25th, revealed not just a single crater, but a double crater formed by the rocket’s impact, posing a new mystery for astronomers to unravel.

June 26, 2022June 26, 2022 by Andy Tomaswick

VY Canis Majoris is Dying, and Astronomers are Watching

Three-dimensional models of astronomical objects can be ridiculously complex. They can range from black holes that light doesn’t even escape to the literal size of the universe and everything in between. But not every object has received the attention needed to develop a complete model of it, but we can officially add another highly complex model to our lists. Astronomers at the University of Arizona have developed a model of VY Canis Majoris, a red hypergiant that is quite possibly the largest star in the Milky Way. And they’re going to use that model to predict how it will die.

June 24, 2022June 24, 2022 by Evan Gough

Recent Supernovae Produced Giant Cavities in the Orion Nebula

This image of the Orion Nebula shows the puzzilng Barnard's Loop feature, a structure made of gas first identified in 1898, Image Credit: Michael Foley

The Orion Nebula is a well-known feature in the night sky and is visible in small backyard telescopes. Orion is a busy place. The region is known for active star formation and other phenomena. It’s one of the most scrutinized features in the sky, and astronomers have observed all kinds of activity there: planets forming in protoplanetary disks, stars beginning their lives of fusion inside collapsing molecular clouds, and the photoevaporative power of massive hot stars as they carve out openings in clouds of interstellar gas.

But supernova explosions are leaving their mark on the Orion Nebula too. New research says supernovae explosions in recent astronomical history are responsible for a mysterious feature first formally identified in the night sky at the end of the 19th century. It’s called Barnard’s Loop, and it’s a gigantic loop of hot gas as large as 300 light-years across.

June 24, 2022June 24, 2022 by David Dickinson

BepiColombo’s Second Mercury Flyby

BepiColombo’s stunning close pass by Mercury on Thursday provides a prelude of what’s to come.

Welcome (briefly) to Mercury, with a planetary flyby hinting at more to come. The joint European Space Agency/Japanese Aerospace Agency’s BepiColombo spacecraft treated us to just that on Thursday, June 23^rd, passing just 200 kilometers from the surface of the innermost world at 9:44 Universal Time (UT). During that brief encounter, BepiColombo got a brief glimpse of its final destination.