Institute of Astronomy

Astronomy News

Australian scientists map millions of galaxies with new telescope

3 hours 50 min ago

A powerful telescope in Australia gives a glimpse of three million galaxies in record time.

Solar Superstorms of the Past Help NASA Scientists Understand Risks for Satellites

4 hours 51 min ago
Portal origin URL: Solar Superstorms of the Past Help NASA Scientists Understand Risks for SatellitesPortal origin nid: 466575Published: Monday, November 30, 2020 - 15:49Featured (stick to top of list): noPortal text teaser: NASA scientists investigated how extreme solar superstorms could endanger low-Earth orbit satellites.Portal image: A image colored in red shows a satellite's view of an eruption from the Sun.

Fast-moving gas flowing away from young star’s asteroid belt may be caused by icy comet vaporisation

30 November 2020 - 8:53am

Astronomers have detected fast-moving carbon monoxide gas flowing away from a young, low-mass star: a unique stage of planetary system evolution which may provide insight into how our own solar system evolved and suggests that the way systems develop may be more complicated than previously thought.

Although it remains unclear how the gas is being ejected so fast, the team of researchers, led by the University of Cambridge, believe it may be produced from icy comets being vaporised in the star’s asteroid belt. The results have been accepted for publication in the Monthly Notices of the Royal Astronomical Society and will be presented at the Five Years After HL Tau virtual conference.

The detection was made with the Atacama Large Millimetre/submillimetre Array (ALMA) in Chile, as part of a survey of young ‘class III’ stars, reported in an earlier paper. Some of these class III stars are surrounded by debris discs, which are believed to be formed by the ongoing collisions of comets, asteroids and other solid objects, known as planetesimals, in the outer reaches of recently formed planetary systems. The leftover dust and debris from these collisions absorbs light from their central stars and re-radiate that energy as a faint glow that can be studied with ALMA.

In the inner regions of planetary systems, the processes of planet formation are expected to result in the loss of all the hottest dust, and class IIII stars are those that are left with - at most - dim, cold dust. These faint belts of cold dust are similar to the known debris discs seen around other stars, similar to the Kuiper belt in our own solar system, which is known to host much larger asteroids and comets.

In the survey, the star in question, ‘NO Lup’, which is about 70% the mass of our sun, was found to have a faint, low-mass dusty disc, but it was the only class III star where carbon monoxide gas was detected, a first for this type of young star with ALMA. While it is known that many young stars still host the gas-rich planet-forming discs they are born with, NO Lup is more evolved, and might have been expected to have lost this primordial gas after its planets had formed.

While the detection of carbon monoxide gas is rare, what made the observation unique was the scale and speed of the gas, which prompted a follow-up study to explore its motion and origins.

“Just detecting carbon monoxide gas was exciting, since no other young stars of this type had been previously imaged by ALMA,” said first author Joshua Lovell, a PhD student from the Cambridge’s Institute of Astronomy. “But when we looked closer, we found something even more unusual: given how far away the gas was from the star, it was moving much faster than expected. This had us puzzled for quite some time.”

Grant Kennedy, Royal Society University Research Fellow at the University of Warwick, who led the modelling work on the study, came up with a solution to the puzzle. “We found a simple way to explain it: by modelling a gas ring, but giving the gas an extra kick outward,” he said. “Other models have been used to explain young discs with similar mechanisms, but this disc is more like a debris disc where we haven’t witnessed winds before. Our model showed the gas is entirely consistent with a scenario in which it’s being launched out of the system at around 22 kilometres per second, which is much higher than any stable orbital speed.”

Further analysis also showed that the gas may be produced during collisions between asteroids, or during periods of sublimation – the transition from a solid to a gaseous phase – on the surface of the star’s comets, expected to be rich in carbon monoxide ice.

There has been recent evidence of this same process in our own solar system from NASA’s New Horizons mission, when it observed the Kuiper Belt object Ultima Thule in 2019 and found sublimation evolution on the surface of the comet, which happened around 4.5 billion years ago. The same event that vaporised comets in our own solar system billions of years ago may have therefore been captured for the first time over 400 light years away, in a process that may be common around planet-forming stars, and have implications for how all comets, asteroids, and planets evolve.

“This fascinating star is shedding light on what kind of physical processes are shaping planetary systems shortly after they are born, just after they have emerged from being enshrouded by their protoplanetary disk,” said co-author Professor Mark Wyatt, also from the Institute of Astronomy. “While we have seen gas produced by planetesimals in older systems, the shear rate at which gas is being produced in this system and its outflowing nature are quite remarkable, and point to a phase of planetary system evolution that we are witnessing here for the first time.”

While the puzzle isn’t fully solved, and further detailed modelling will be required to understand how the gas is being ejected so quickly, what is sure is that this system is set to be the target of more intense follow-up measurements.

“We’re hoping that ALMA will be back online next year, and we’ll be making the case to observe this system again in greater detail,” said Lovell. “Given how much we have learned about this early stage of planetary system evolution with only a short 30-minute observation, there is still so much more that this system can tell us.”

 

References:
1: J.B. Lovell et al. ‘Rapid CO gas dispersal from NO Lup’s class III circumstellar disc.’ Paper presented at Five Years After HL Tau. 7-11 December 2020.

2: J.B. Lovell et al. ‘ALMA Survey of Class III stars: Early planetesimal formation and Rapid disc dispersal’, DOI: https://doi.org/10.1093/mnras/staa3335  

A unique stage of planetary system evolution has been imaged by astronomers, showing fast-moving carbon monoxide gas flowing away from a star system over 400 light years away, a discovery that provides an opportunity to study how our own solar system developed.

Given how much we have learned about this early stage of planetary system evolution with only a short observation, there is still so much more that this system can tell usJoshua LovellInstitute of AstronomyArtist's impression of No Lup system


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Galaxy Survives Black Hole’s Feast – For Now

28 November 2020 - 2:31pm
Portal origin URL: Galaxy Survives Black Hole’s Feast – For NowPortal origin nid: 466527Published: Friday, November 27, 2020 - 07:30Featured (stick to top of list): noPortal text teaser: The hungriest of black holes are thought to gobble up so much surrounding material they put an end to the life of their host galaxy by creating an energetic object called a quasar. Now, researchers found a galaxy that is surviving the black hole’s ravenous forces, continuing to birth about 100 Sun-sized stars a year.Portal image: Illustration of active black hole glowing at the center of galaxy with blue stars surrounded by a ring of dust.

Journeys of discovery: Jocelyn Bell Burnell and pulsars

28 November 2020 - 2:27pm

"On 28 November 1967, it came again, a string of pulses one-and-a third seconds apart." This was not the work of Little Green Men. Jocelyn Bell had discovered pulsars.

Neutrino detection gets to the core of the Sun

26 November 2020 - 9:31am

Nature, Published online: 25 November 2020; doi:10.1038/d41586-020-03238-9

The first detection of neutrinos produced by the Sun’s secondary solar-fusion cycle paves the way for a detailed understanding of the structure of the Sun and of the formation of massive stars.

Experimental evidence of neutrinos produced in the CNO fusion cycle in the Sun

26 November 2020 - 9:30am

Nature, Published online: 25 November 2020; doi:10.1038/s41586-020-2934-0

Direct experimental evidence of the carbon–nitrogen–oxygen fusion cycle in the Sun is provided by the detection of neutrinos emitted during this process.

Neutrinos give insights into the workings of the Sun’s core

26 November 2020 - 9:30am

Nature, Published online: 25 November 2020; doi:10.1038/d41586-020-03347-5

Scientists have finally confirmed the existence of a CNO cycle fusion reaction in the Sun, and why women’s contraception research needs a reboot.

Explain ESA’s last-minute ditching of new space telescope

25 November 2020 - 9:17am

Nature, Published online: 24 November 2020; doi:10.1038/d41586-020-03288-z

Explain ESA’s last-minute ditching of new space telescope

Hints of twisted light offer clues to dark energy’s nature

25 November 2020 - 9:17am

Nature, Published online: 24 November 2020; doi:10.1038/d41586-020-03201-8

Cosmologists suggest that an exotic substance called quintessence could be accelerating the Universe’s expansion — but the evidence is still tentative.

A Small Satellite With Planetary Ambitions

25 November 2020 - 9:15am
PROJECT

CubeSat Particle Aggregation and Collision Experiment, or Q-PACE

SNAPSHOT

Q-PACE will capture video of thousands of gentle collisions between particles in microgravity to understand the earliest steps in planet formation.

Undergraduate students Clayton White (left) and Jonathan Kessluk, and graduate student Stephanie Jarmak, test the Q-PACE electronics. (Credit: University of Central Florida)

A NASA-sponsored team at the University of Central Florida (UCF) has built a small satellite designed to study how tiny particles collide and aggregate in microgravity. The spacecraft, called the CubeSat Particle Aggregation and Collision Experiment, or Q-PACE, has been integrated onto  Virgin Orbit’s LauncherOne space vehicle, and is scheduled for launch no earlier than December 8, 2020. Q-PACE is part of NASA’s Educational Launch of Nanosatellites (ELaNa) program. The mission was selected in 2015 as part of NASA’s Small Innovative Missions for Planetary Exploration (SIMPLEx) Program.

The first steps of planet formation involve the formation of centimeter-scale objects through collisional aggregation of dust particles. These centimeter-scale objects, dubbed pebbles, then agglomerate into asteroid-sized objects called planetesimals aided by gravitational instabilities within the protoplanetary nebula. The same collisional processes also take place in the rings of Saturn and the other giant planets, controlling the rate of spreading of the rings and the formation of clumps and moonlets within the rings. Q-PACE will take advantage of the microgravity environment in low-Earth orbit, which allows particles to collide at low speeds (from less than a mm/s to several cm/s), to study the transition between bouncing, sticking, and fragmentation of aggregates. Q-PACE will capture information about thousands to tens of thousands of collisions between different types of particles to enable better understanding of the formation of pebbles and the collisional evolution of swarms of pebbles.

The Q-PACE Experiment Test Chamber (ETC)

The 3U (10 x 10 x 30 cm) Q-PACE CubeSat carries a small Experiment Test Chamber (ETC) containing particles of various sizes, densities, materials, and shapes, ranging from micron-sized silicate dust to centimeter-sized quartz spheres. The ETC also includes a collection of chondrules, small pieces of meteorites that are some of the first solids to have formed in the gaseous nebula that became our solar system. While in Earth orbit, the ETC will be shaken at various speeds and along all three axes to induce collisions between the particles. The particles will be backlit in the ETC, and the experiments will be recorded on video by a COTS camera powered by a $35 Raspberry Pi microcontroller with custom radiation spot shielding. Data will be recorded at 90 frames per second to enable precise tracking of the particles during collisions. After the ETC is shaken, the resulting motion of the particles will be recorded until motion stops. Preliminary experiments suggest this entire process will take less than five minutes. 

The ETC is the heart of Q-PACE and engineering the experiment to fit in the small CubeSat form factor was a significant challenge. UCF students iterated the ETC design and developed several prototypes to obtain the final product.

The Q-PACE mission will last up to three years, providing the opportunity to study adhesion and fragmentation events that happen only rarely, such as near-simultaneous collision of three or more particles. The mission will proceed over several phases with the introduction of different types of particles into the ETC, beginning with large solid spherical particles, and finishing with aggregates of micron-sized dust and chondrules. The large number of collisions to be recorded by Q-PACE over the course of the mission will enable a probabilistic description of collisional outcomes in the protoplanetary disk.

The Q-PACE satellite, ready for environmental testing, is powered by batteries charged by solar panels. (Credit: University of Central Florida)

The small spacecraft will be powered by the Sun. Solar panels will charge batteries to power the test chamber, onboard camera, spacecraft control, and communications back to ground stations at the University of Central Florida (UCF) and the University of Arkansas. Because of the large volume of video data to be generated, Q-PACE will use data compression and multiple downlinks to complete an experiment. Both undergraduate and graduate students at UCF were heavily involved in the design and construction of Q-PACE, under the direction of Principal Investigator Joshua Colwell, Co-Investigators Julie Brisset and Addie Dove, and systems engineer Doug Maukonen. Larry Roe at the University of Arkansas and Jürgen Blum at the Technical University of Braunschweig complete the Q-PACE science team.

PROJECT LEADS

Dr. Joshua Colwell, University of Central Florida

SPONSORING ORGANIZATION

Planetary Science Division‘s Small Innovative Missions for Planetary Exploration (SIMPLEx) program

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Master Image: 

Iconic Puerto Rico telescope to be dismantled amid collapse fears

20 November 2020 - 9:02am

The iconic Arecibo radio telescope in Puerto Rico is to be dismantled, officials announce.

Legendary Arecibo telescope will close forever — scientists are reeling

20 November 2020 - 9:01am

Nature, Published online: 19 November 2020; doi:10.1038/d41586-020-03270-9

New satellite image reveals the damage that shut down the facility, ending an era in astronomical observation.

A relic star cluster under the floor

20 November 2020 - 8:59am

An extremely metal-deficient globular cluster in the Andromeda Galaxy

20 November 2020 - 8:58am

Globular clusters (GCs) are dense, gravitationally bound systems of thousands to millions of stars. They are preferentially associated with the oldest components of galaxies, so measurements of their composition can constrain the build-up of chemical elements in galaxies during the early Universe. We report a massive GC in the Andromeda Galaxy (M31), RBC EXT8, that is extremely depleted in heavy elements. Its iron abundance is about 1/800 that of the Sun and about one-third that of the most iron-poor GCs previously known. It is also strongly depleted in magnesium. These measurements challenge the notion of a metallicity floor for GCs and theoretical expectations that massive GCs could not have formed at such low metallicities.

A blue ring nebula from a stellar merger several thousand years ago

19 November 2020 - 9:19am

Nature, Published online: 18 November 2020; doi:10.1038/s41586-020-2893-5

Observations and stellar evolution models of a blue ring nebula and its central star (TYC 2597-735-1) suggest that the remnant star merged with a lower-mass companion several thousand years ago.

The Cosmic Dust in Your Bones—NASA’s Webb Telescope Will Investigate the Intertwined Origins of Dust and Life

19 November 2020 - 9:17am
Portal origin URL: The Cosmic Dust in Your Bones—NASA’s Webb Telescope Will Investigate the Intertwined Origins of Dust and LifePortal origin nid: 466274Published: Tuesday, November 17, 2020 - 11:56Featured (stick to top of list): noPortal text teaser: Astronomers find themselves in a similar position when calculating the amount of dust galaxies should have; there is more dust than expected, and they don’t know where it’s coming from.Portal image: The VISIR instrument on ESO’s VLT captured this stunning image of a newly-discovered massive binary star system.