Astronomy

If all goes well, the Chang’e 6 probe will be the first ever to land on the far side of the moon to take samples and bring them back to Earth

If all goes well, the Chang’e 6 probe will be the first ever to land on the far side of the moon to take samples and bring them back to Earth

Strange bursts of radio waves called FRBs have long been mysterious, and one of the most famous sources of these flashes may have an unexpected planet

Strange bursts of radio waves called FRBs have long been mysterious, and one of the most famous sources of these flashes may have an unexpected planet

Boeing's Starliner is finally ready to fly astronauts, after several years of delay. The capsule's designers put the extra time to good use, NASA and Boeing representatives say.

Stay tuned for a new era of Science Quickly.

This week in the moonless dark, the Summer Triangle appears over the eastern treetops star by star. Leo walks down toward the west. And the Sombrero Galaxy positions itself ideally on the south meridian for your telescope.

The post This Week's Sky at a Glance, May 3 – 12 appeared first on Sky & Telescope.

Plants are often celebrated for the parts that are easy to see – flower, leaves, fruit – but scientists are uncovering the secrets of their more mysterious underground networks

Plants are often celebrated for the parts that are easy to see – flower, leaves, fruit – but scientists are uncovering the secrets of their more mysterious underground networks

Image: This image may resemble the surface of Mars, but it was actually captured by the Copernicus Sentinel-2 mission, revealing the stunning terrain of northwest Namibia.

ESA is committed to almost halve its greenhouse gas emissions linked to energy consumption by 2025 compared to 2019 levels. But how can ESA keep accelerating the use of space for the sustainable development of society while reducing its emissions?

The air and dust in climbing centres contain high levels of rubber particles from the soles of climbing shoes, some of which contain toxic additives

The air and dust in climbing centres contain high levels of rubber particles from the soles of climbing shoes, some of which contain toxic additives

A few weeks ago, a team of engineers carefully extracted ESA's EarthCARE satellite from its protective transport container, initiating a meticulous process of inspection, testing and preparation for its liftoff later this month from Vandenberg Space Force Base in California.

Amidst an extensive checklist of tasks, was a rigorous effort to guarantee that the satellite is in pristine condition, underscoring the thorough attention to detail essential to making the satellite ready for launch.

Europe’s newest rocket soon launches, taking with it many space missions each with a unique objective, destination and team at home, cheering them on. Whether launching new satellites to look back and study Earth, peer out to deep space or test important new technologies in orbit, Ariane 6’s first flight will showcase the versatility and flexibility of this impressive, heavy-lift launcher. Read on for all about EXOpod Nova, then see who else is flying first.

Climate change could be fueling bumblebee population loss by making hives too hot to handle

Climate change could be fueling bumblebee population loss by making hives too hot to handle

A beautiful nebula in the southern hemisphere with a binary star at it’s center seems to break our standard models of stellar evolution. But new data from the European Southern Observatory (ESO) suggests that there may once have been three stars, and that one was destroyed in a catastrophic collision.

About 3800 light years away, in the Southern constellation of Norma, you can find an object called the Dragon’s Egg Nebula (catalogue number NGC 6164). In the heart of this nebula lies a double star known as HD 148937. The pair are bright enough to be seen through binoculars and small telescopes but are far enough away that they only appear as a single star. Both of the stars that make up the pair are hot young blue giants, but the nebula surrounding them is quite unusual, which is why astronomers have been studying them for a long time.

Dr Abigail Frost is an astronomer at the European Southern Observatory (ESO) in Chile, and she has been paying attention to this system for the past nine years.

“When doing background reading, I was struck by how special this system seemed,” she says. “A nebula surrounding two massive stars is a rarity, and it really made us feel like something cool had to have happened in this system. When looking at the data, the coolness only increased.”

Frost, like other astronomers before her, have noticed many strange features about the nebula. Most obviously, hot young stars like these aren’t usually found in nebulae, as their intense radiation tends to disperse surrounding dust and gas quite efficiently. But beyond that, the nebula itself has an unusual composition. If this nebula were the remains of the gas cloud that birthed these stars, it would be composed almost entirely of molecular hydrogen. But instead, it contains heavier elements like oxygen, nitrogen and carbon. Old stars create these elements by fusing Helium, and they eject them in their final stages of life. But that cannot be the source of this nebula, as the stars are still young.

The stars themselves have their own mysteries. The larger of the two has a strong magnetic field. Magnetic fields in stars like our Sun are formed when the thick central shell of super-heated plasma circulates. Much of the heat from the Sun’s core is transferred to the surface by convection: hot plasma near the core bubbles up towards the surface, where it cools and then sinks back down. Plasma is electrically charged, and all that charge moving generates a magnetic field, in what scientists call a dynamo effect.

But truly massive stars, like those in HD 148937, are so big that heat can simply radiate out from the core. There is such a large distance from the core to the surface that the temperature gradient is very gradual. There is nowhere inside the star with a high enough temperature differential to start convection, so there is no flow of material to generate a magnetic field. Nevertheless, the star has a magnetic field, which leads to the next oddity: magnetic stars experience a braking effect, causing their spin to gradually slow. So, this star, with its strong magnetic field which it should not have, spins rapidly, which the magnetic field should have prevented.

Fighting Dragons of Ara (NGC 6188 and 6164) © Michael Sidonio

But that’s not all! The primary star is at least 1.5 million years younger than its companion. According to Dr Frost, this shouldn’t be possible: “After a detailed analysis, we could determine that the more massive star appears much younger than its companion, which doesn’t make any sense since they should have formed at the same time”

If this system of stars and nebula doesn’t match what our models of stellar evolution tell us to expect, then how do we explain all these anomalies?

“We think this system had at least three stars originally; two of them had to be close together at one point in the orbit whilst another star was much more distant,” explains Hugues Sana, a professor at KU Leuven in Belgium and the principal investigator of the observations. “The two inner stars merged in a violent manner, creating a magnetic star and throwing out some material, which created the nebula. The more distant star formed a new orbit with the newly merged, now-magnetic star, creating the binary we see today at the centre of the nebula.”

In other words, the system was originally a triple star, not a double. Triple systems tend to be quite unstable, and usually end up ejecting one of their members. But sometimes the third star will smash dramatically into one of its companions instead. Nobody has ever seen a stellar collision, but computer modelling predicts a number of things, which we see in NGC 6164. A star is, essentially, a vast and massive cloud of gas, so big and heavy that its central regions are compressed to an enormous temperature and pressure. So, when two stars collide, these masses of gas merge chaotically. The different layers mix, dredging nuclear ash (like helium, nitrogen, carbon and oxygen) from the core to the surface. A lot of the gas, including the heavier elements, is ejected to create a vast new nebula. What’s left will collapse back inwards, settling down into a new star, with a rapid spin to match. And finally, the turbulence of the collision generates and sustains a powerful magnetic field.

This sequence of events has long been predicted by astronomers trying to model stellar mergers, and the nine years of work by Dr Frost could well provide the evidence to confirm that they are right. The metal-rich gas of NGC 6164, the youthful appearance of the primary star, it’s rapid spin and strong magnetic field all seem to confirm that this was indeed once a three body system that ended with a collision between two stars.

Read the original press release at https://www.eso.org/public/news/eso2407/

The post Two Stars in a Binary System are Very Different. It's Because There Used to be Three appeared first on Universe Today.

The history of astronomy and observatories is full of stories about astronomers going higher and higher to get better views of the Universe. On Earth, the best locations are at places such as the Atacama Desert in Chile. So, that’s where the University of Tokyo Atacama Observatory just opened its high-altitude eye on the sky, atop Cerro Chajnantor.

This unique new observatory, which was just commissioned on April 30th, sits at 5,640 meters (3.5 miles) above sea level, making it the highest observatory in the world—with a Guinness World Record recognition to prove it. The idea is to use this position in one of the driest areas of the world to get a closer look at planet-forming regions, evolving galaxies, and the earliest accessible epochs of cosmic history.

“Thanks to the height and arid environment, TAO will be the only ground-based telescope in the world capable of clearly viewing mid-infrared wavelengths. This area of the spectrum is extremely good for studying the environments around stars, including planet-forming regions,” said Professor Takashi Miyata, director of the Atacama Observatory of the Institute of Astronomy and manager of the observatory’s construction.

Building an observatory at such a high altitude may give astronomers a great view, but it’s also is a difficult place to work. For that reason, the University cooperated closely with locals to build the observatory safely. It will be operated remotely as much as possible, to avoid risking human life in what can be very adverse conditions.

At 5,640 meters, the summit of Cerro Chajnantor, where Tokyo Atacama Observatory is located, allows the telescope to be above most of the moisture that would otherwise limit its infrared sensitivity. ©2024 TAO project CC-BY-ND Why a Mid-infrared Observatory?

Objects and events in the Universe give off light across the electromagnetic spectrum. On Earth, we can detect much of that light, but not all of it. For example, Earth’s atmosphere absorbs many infrared wavelengths. So, the higher a telescope is placed, the more infrared it can “see”. Going to space (as astronomers have done with JWST, for example) is great, and a lot gets accomplished there. But astronomers can do quite a lot of very good astronomy at high altitudes, where conditions are dry and the atmosphere is thinner.

Mid-infrared is a particularly interesting “regime” of the electromagnetic spectrum. This is where we can start to “see” objects such as asteroids and planets. They re-radiate heat from their stars in the mid-infrared range. The same thing happens with dust around stars. It gets warmed and re-radiates in the mid-infrared. Disks of material around newborn stars—called protoplanetary disks—give off infrared radiation. Since these disks are where new planets form, infrared views give more detail about their evolution.

Mid-infrared studies of distant galaxies offer insight into their formation histories, as well as their star-formation rates. In addition, that range of wavelengths opens up a window into the activities and existence of active galactic nuclei. And, there’s a lot more that mid-infrared observations of the Universe can tell astronomers.

TAO Specs

According to Professor Yuzuru Yoshii, the TAO project lead and principal investigator, the new observatory should provide unique insights at each wavelength it studies. “I’m seeking to elucidate mysteries of the Universe, such as dark energy and primordial first stars,” said Yoshii. “For this, you need to view the sky in a way that only TAO makes possible.”

A schematic of the Tokyo Atacama Observatory telescope. Courtesy TAO project.

The heart of TAO is a 6.5-meter mirror that will feed incoming light into specialized instruments. The Simultaneous-color Wide-field Infrared Multi-object Spectrograph (SWIMS) can observe a large area of the sky and simultaneously observe two wavelengths of light. The other is the Mid-Infrared Multi-field Imager for gaZing at the UnKnown Universe (MIMIZUKU). It peers into the dustier regions of the Universe. Both will allow astronomers to efficiently collect information on a diverse range of galaxies and other structures in the Universe.

“Analysis of the SWIMS observation data will provide insight into the formation of these including the evolution of the supermassive black holes at their centers,” said Assistant Professor Masahiro Konishi. “New telescopes and instruments naturally help advance astronomy. I hope the next generation of astronomers use TAO and other ground-based, and space-based, telescopes, to make unexpected discoveries that challenge our current understanding and explain the unexplained.”

For More Information

The TAO Project
World’s Highest Observatory Explores the Universe

The post The Highest Observatory in the World Comes Online appeared first on Universe Today.

NASA's Lucy spacecraft serendipitously found a small moonlet orbiting the mission's asteroid target Dinkinesh. Scientists named it Selam, and have now learned that Selam is a cosmic toddler.