Using telescopes from the European Southern Observatory (ESO) and other organisations around the world, astronomers have spotted a rare blast of light from a star being ripped apart by a supermassive black hole. The phenomenon, known as a tidal disruption event, is the closest such flare recorded to date at just over 215 million light-years from Earth, and has been studied in unprecedented detail. The research is published today in Monthly Notices of the Royal Astronomical Society.
“The idea of a black hole ‘sucking in’ a nearby star sounds like science fiction. But this is exactly what happens in a tidal disruption event,”
says Matt Nicholl, a lecturer and Royal Astronomical Society research fellow at the University of Birmingham, UK, and the lead author of the new study. But these tidal disruption events, where a star experiences what’s known as spaghettification as it’s sucked in by a black hole, are rare and not always easy to study. The team of researchers pointed ESO’s Very Large Telescope (VLT) and ESO’s New Technology Telescope (NTT) at a new flash of light that occurred last year close to a supermassive black hole, to investigate in detail what happens when a star is devoured by such a monster.
Astronomers know what should happen in theory.
“When an unlucky star wanders too close to a supermassive black hole in the centre of a galaxy, the extreme gravitational pull of the black hole shreds the star into thin streams of material,”
explains study author Thomas Wevers, an ESO Fellow in Santiago, Chile, who was at the Institute of Astronomy, University of Cambridge, UK, when he conducted the work. As some of the thin strands of stellar material fall into the black hole during this spaghettification process, a bright flare of energy is released, which astronomers can detect.
Although powerful and bright, up to now astronomers have had trouble investigating this burst of light, which is often obscured by a curtain of dust and debris. Only now have astronomers been able to shed light on the origin of this curtain.
“We found that, when a black hole devours a star, it can launch a powerful blast of material outwards that obstructs our view,”
explains Samantha Oates, also at the University of Birmingham. This happens because the energy released as the black hole eats up stellar material propels the star’s debris outwards.
The discovery was possible because the tidal disruption event the team studied, AT2019qiz, was found just a short time after the star was ripped apart.
“Because we caught it early, we could actually see the curtain of dust and debris being drawn up as the black hole launched a powerful outflow of material with velocities up to 10 000 km/s,” says Kate Alexander, NASA Einstein Fellow at Northwestern University in the US. “This unique ‘peek behind the curtain’ provided the first opportunity to pinpoint the origin of the obscuring material and follow in real time how it engulfs the black hole.”
The team carried out observations of AT2019qiz, located in a spiral galaxy in the constellation of Eridanus, over a 6-month period as the flare grew in luminosity and then faded away.
“Several sky surveys discovered emission from the new tidal disruption event very quickly after the star was ripped apart,” says Wevers. “We immediately pointed a suite of ground-based and space telescopes in that direction to see how the light was produced.”
Multiple observations of the event were taken over the following months with facilities that included X-shooter and EFOSC2, powerful instruments on ESO’s VLT and ESO’s NTT, which are situated in Chile. The prompt and extensive observations in ultraviolet, optical, X-ray and radio light revealed, for the first time, a direct connection between the material flowing out from the star and the bright flare emitted as it is devoured by the black hole.
“The observations showed that the star had roughly the same mass as our own Sun, and that it lost about half of that to the monster black hole, which is over a million times more massive,”
says Nicholl, who is also a visiting researcher at the University of Edinburgh.
The research helps us better understand supermassive black holes and how matter behaves in the extreme gravity environments around them. The team say AT2019qiz could even act as a ‘Rosetta stone’ for interpreting future observations of tidal disruption events. ESO’s Extremely Large Telescope (ELT), planned to start operating this decade, will enable researchers to detect increasingly fainter and faster evolving tidal disruption events, to solve further mysteries of black hole physics.
A team of astronomers have identified the first direct evidence that groups of stars can tear apart their planet-forming disc, leaving it warped and with tilted rings. This new research suggests exotic planets, not unlike Tatooine in Star Wars, may form in inclined rings in bent discs around multiple stars. The results were made possible thanks to observations with the European Southern Observatory’s Very Large Telescope (ESO’s VLT) and the Atacama Large Millimeter/submillimeter Array (ALMA).
Our Solar System is remarkably flat, with the planets all orbiting in the same plane. But this is not always the case, especially for planet-forming discs around multiple stars, like the object of the new study: GW Orionis. This system, located just over 1300 light-years away in the constellation of Orion, has three stars and a deformed, broken-apart disc surrounding them.
“Our images reveal an extreme case where the disc is not flat at all, but is warped and has a misaligned ring that has broken away from the disc,”
says Stefan Kraus, a professor of astrophysics at the University of Exeter in the UK who led the research published today in the journal Science. The misaligned ring is located in the inner part of the disc, close to the three stars.
The new research also reveals that this inner ring contains 30 Earth-masses of dust, which could be enough to form planets.
“Any planets formed within the misaligned ring will orbit the star on highly oblique orbits and we predict that many planets on oblique, wide-separation orbits will be discovered in future planet imaging campaigns, for instance with the ELT,”
says team member Alexander Kreplin of the University of Exeter, referring to ESO’s Extremely Large Telescope, which is planned to start operating later this decade. Since more than half the stars in the sky are born with one or more companions, this raises an exciting prospect: there could be an unknown population of exoplanets that orbit their stars on very inclined and distant orbits.
“We found that the three stars do not orbit in the same plane, but their orbits are misaligned with respect to each other and with respect to the disc,”
says Alison Young of the Universities of Exeter and Leicester and a member of the team.
They also observed the system with the SPHERE instrument on ESO’s VLT and with ALMA, in which ESO is a partner, and were able to image the inner ring and confirm its misalignment. ESO’s SPHERE also allowed them to see, for the first time, the shadow that this ring casts on the rest of the disc. This helped them figure out the 3D shape of the ring and the overall disc.
The international team, which includes researchers from the UK, Belgium, Chile, France and the US, then combined their exhaustive observations with computer simulations to understand what had happened to the system. For the first time, they were able to clearly link the observed misalignments to the theoretical “disc-tearing effect”, which suggests that the conflicting gravitational pull of stars in different planes can warp and break their discs.
Their simulations showed that the misalignment in the orbits of the three stars could cause the disc around them to break into distinct rings, which is exactly what they see in their observations. The observed shape of the inner ring also matches predictions from numerical simulations on how the disc would tear.
Interestingly, another team who studied the same system using ALMA believe another ingredient is needed to understand the system.
“We think that the presence of a planet between these rings is needed to explain why the disc tore apart,”
says Jiaqing Bi of the University of Victoria in Canada who led a study of GW Orionis published in The Astrophysical Journal Letters in May this year. His team identified three dust rings in the ALMA observations, with the outermost ring being the largest ever observed in planet-forming discs.
Future observations with ESO’s ELT and other telescopes may help astronomers fully unravel the nature of GW Orionis and reveal young planets forming around its three stars.
7:58 pm EDT: The upper stage firing went as planned and the probe was successfully deployed. Communications with the vehicle have been established and the solar panels were deployed. The spacecraft’s next job is to use its attitude thrusters to orient itself so as to maximize power generation from the sun. The probe will reach Mars next February. After going into orbit, the spacecraft’s instruments will study the atmosphere and weather on the Red Planet.
6:31 pm EDT: The launch has succeeded so far in reaching low earth orbit. The upper stage with the probe is now in a coast period before the stage will fire its engine for 4 minutes to send the Hope probe on its route to Mars. The stage will then separate from the probe soon after the engine boost ends. The firing should start at around 6:54 pm EDT (22:54 UTC).
Observations made with the European Southern Observatory’s Very Large Telescope (ESO’s VLT) have revealed the telltale signs of a star system being born. Around the young star AB Aurigae lies a dense disc of dust and gas in which astronomers have spotted a prominent spiral structure with a ‘twist’ that marks the site where a planet may be forming. The observed feature could be the first direct evidence of a baby planet coming into existence.
“Thousands of exoplanets have been identified so far, but little is known about how they form,”
says Anthony Boccaletti who led the study from the Observatoire de Paris, PSL University, France. Astronomers know planets are born in dusty discs surrounding young stars, like AB Aurigae, as cold gas and dust clump together. The new observations with ESO’s VLT, published in Astronomy & Astrophysics, provide crucial clues to help scientists better understand this process.
“We need to observe very young systems to really capture the moment when planets form,”
says Boccaletti. But until now astronomers had been unable to take sufficiently sharp and deep images of these young discs to find the ‘twist’ that marks the spot where a baby planet may be coming to existence.
The new images feature a stunning spiral of dust and gas around AB Aurigae, located 520 light-years away from Earth in the constellation of Auriga (The Charioteer). Spirals of this type signal the presence of baby planets, which ‘kick’ the gas, creating
“disturbances in the disc in the form of a wave, somewhat like the wake of a boat on a lake,”
explains Emmanuel Di Folco of the Astrophysics Laboratory of Bordeaux (LAB), France, who also participated in the study. As the planet rotates around the central star, this wave gets shaped into a spiral arm. The very bright yellow ‘twist’ region close to the centre of the new AB Aurigae image, which lies at about the same distance from the star as Neptune from the Sun, is one of these disturbance sites where the team believe a planet is being made.
Observations of the AB Aurigae system made a few years ago with the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, provided the first hints of ongoing planet formation around the star. In the ALMA images, scientists spotted two spiral arms of gas close to the star, lying within the disc’s inner region. Then, in 2019 and early 2020, Boccaletti and a team of astronomers from France, Taiwan, the US and Belgium set out to capture a clearer picture by turning the SPHERE instrument on ESO’s VLT in Chile toward the star. The SPHERE images are the deepest images of the AB Aurigae system obtained to date.
With SPHERE’s powerful imaging system, astronomers could see the fainter light from small dust grains and emissions coming from the inner disc. They confirmed the presence of the spiral arms first detected by ALMA and also spotted another remarkable feature, a ‘twist’, that points to the presence of ongoing planet formation in the disc.
“The twist is expected from some theoretical models of planet formation,”
says co-author Anne Dutrey, also at LAB.
“It corresponds to the connection of two spirals — one winding inwards of the planet’s orbit, the other expanding outwards — which join at the planet location. They allow gas and dust from the disc to accrete onto the forming planet and make it grow.”
ESO is constructing the 39-metre Extremely Large Telescope, which will draw on the cutting-edge work of ALMA and SPHERE to study extrasolar worlds. As Boccaletti explains, this powerful telescope will allow astronomers to get even more detailed views of planets in the making.
“We should be able to see directly and more precisely how the dynamics of the gas contributes to the formation of planets,”
A sampling of recent articles, videos, and images from space-related science news items (find previous roundups here):
** What Does a Black Hole Look Like: How We Got Our First Picture – Dr. Eliot Quataert of the University of California, Berkeley gave this recent Silicon Valley Astronomy Lecture:
Black holes are one of the most remarkable predictions of Einstein’s theory of gravity: so much material is compressed into such a small volume that nothing, not even light, can escape. In Spring 2019, the world-wide Event Horizon Telescope released the first real picture of gas around a massive black hole and the “shadow” it makes as the gas swirls into the black hole. Dr. Quataert describes how these pioneering observations were made and what they have taught us about black
NASA’s Kepler spacecraft was designed to find exoplanets by looking for stars that dim as a planet crosses the star’s face. Fortuitously, the same design makes it ideal for spotting other astronomical transients – objects that brighten or dim over time. A new search of Kepler archival data has uncovered an unusual super-outburst from a previously unknown dwarf nova. The system brightened by a factor of 1,600 over less than a day before slowly fading away.
The star system in question consists of a white dwarf star with a brown dwarf companion about one-tenth as massive as the white dwarf. A white dwarf is the leftover core of an aging Sun-like star and contains about a Sun’s worth of material in a globe the size of Earth. A brown dwarf is an object with a mass between 10 and 80 Jupiters that is too small to undergo nuclear fusion.
The brown dwarf circles the white dwarf star every 83 minutes at a distance of only 250,000 miles (400,000 km) – about the distance from Earth to the Moon. They are so close that the white dwarf’s strong gravity strips material from the brown dwarf, sucking its essence away like a vampire. The stripped material forms a disk as it spirals toward the white dwarf (known as an accretion disk).
It was sheer chance that Kepler was looking in the right direction when this system underwent a super-outburst, brightening by more than 1,000 times. In fact, Kepler was the only instrument that could have witnessed it, since the system was too close to the Sun from Earth’s point of view at the time. Kepler’s rapid cadence of observations, taking data every 30 minutes, was crucial for catching every detail of the outburst.
The event remained hidden in Kepler’s archive until identified by a team led by Ryan Ridden-Harper of the Space Telescope Science Institute (STScI), Baltimore, Maryland, and the Australian National University, Canberra, Australia. “In a sense, we discovered this system accidentally. We weren’t specifically looking for a super-outburst. We were looking for any sort of transient,” said Ridden-Harper.
Kepler captured the entire event, observing a slow rise in brightness followed by a rapid intensification. While the sudden brightening is predicted by theories, the cause of the slow start remains a mystery. Standard theories of accretion disk physics don’t predict this phenomenon, which has subsequently been observed in two other dwarf nova super-outbursts.
NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered its first Earth-size planet in its star’s habitable zone, the range of distances where conditions may be just right to allow the presence of liquid water on the surface. Scientists confirmed the find, called TOI 700 d, using NASA’s Spitzer Space Telescope and have modeled the planet’s potential environments to help inform future observations.
“TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars,” said Paul Hertz, astrophysics division director at NASA Headquarters in Washington. “Planets around nearby stars are easiest to follow-up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS. Confirming the planet’s size and habitable zone status with Spitzer is another win for Spitzer as it approaches the end of science operations this January.”
In 2019, when Wolf Cukier finished his junior year at Scarsdale High School in New York, he joined NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as a summer intern. His job was to examine variations in star brightness captured by NASA’s Transiting Exoplanet Survey Satellite (TESS) and uploaded to the Planet Hunters TESS citizen science project.
“I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit,” Cukier said. “About three days into my internship, I saw a signal from a system called TOI 1338. At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet.”
Engineers for NASA’s Voyager 2 spacecraft are working to return the mission to normal operating conditions after one of the spacecraft’s autonomous fault protection routines was triggered. Multiple fault protection routines were programmed into both Voyager 1 and Voyager 2 in order to allow the spacecraft to automatically take actions to protect themselves if potentially harmful circumstances arise. At NASA’s Jet Propulsion Laboratory in Pasadena, California, engineers are still communicating with the spacecraft and receiving telemetry.
Launched in 1977, Voyager 1 and Voyager 2 are both in interstellar space, making them the most distant human-made objects in the solar system. On Saturday, Jan. 25, Voyager 2 didn’t execute a scheduled maneuver in which the spacecraft rotates 360 degrees in order to calibrate its onboard magnetic field instrument. Analysis of the telemetry from the spacecraft indicated that an unexplained delay in the onboard execution of the maneuver commands inadvertently left two systems that consume relatively high levels of power operating at the same time. This caused the spacecraft to overdraw its available power supply.
It’s a long way to make a service call:
It has taken the team several days to assess the current situation primarily because of Voyager 2’s distance from Earth – about 11.5 billion miles (18.5 billion kilometers). Communications traveling at the speed of light take about 17 hours to reach the spacecraft, and it takes another 17 hours for a response from the spacecraft to return to Earth. As a result, mission engineers have to wait about 34 hours to find out if their commands have had the desired effect on the spacecraft.
In the month of December 2019 the Sun continued its longest stretch of overall sunspot inactivity ever recorded, reaching seven months in length. At no point since the last grand minimum in the 1600s have scientists ever seen so few sunspots over so long a time period.
December saw only two sunspots, both becoming active on the same day, December 24. Both also had a polarity belonging to the next solar cycle, providing evidence that we will have another sunspot maximum sometime in the next five years, and that we are not heading to another grand minimum where there are no sunspots for decades.
At 4:37 a.m. EST on Jan. 29, 2020, NASA’s Parker Solar Probe broke speed and distance records as it completed its fourth close approach of the Sun. The spacecraft traveled 11.6 million miles from the Sun’s surface at perihelion, reaching a speed of 244,225 miles per hour. These achievements topple Parker Solar Probe’s own previous records for closest spacecraft to the Sun — previously about 15 million miles from the Sun’s surface — and fastest human-made object, before roughly 213,200 miles per hour.
Parker Solar Probe will continue to fly ever closer to the Sun on its seven-year journey, exploring regions of space never visited before and providing scientists with key measurements to help unveil the mysteries of the solar corona and wind.
As with most of Parker Solar Probe’s close approaches, the spacecraft is out of contact with Earth for several days around perihelion.
There’s a wind that emanates from the Sun. It blows not like a soft whistle but like a hurricane’s scream. Made of electrons, protons and heavier ions, the solar wind courses through the solar system at roughly 1 million mph (1.6 million kph), barreling over everything in its path. Yet through the wind’s roar, NASA’s Parker Solar Probe hears the small chirps, squeaks and rustles that hint at the origin of this mysterious and ever-present wind. The spacecraft’s FIELDS instrument can eavesdrop on the electric and magnetic fluctuations caused by plasma waves. The Parker Solar Probe it can “hear” when the waves and particles interact with one another, recording frequency and amplitude information about these plasma waves that scientists could then play as sound waves. And it results in some striking sounds. Solar wind sounds playlist: https://soundcloud.com/jhu-apl/sets/s…
It’s more massive than all the other planets combined. In nearly four years at Jupiter the Juno spacecraft has returned science that is revolutionizing our understanding of this gigantic world. Principal investigator Scott Bolton shows us the mysterious cyclones at its poles and that famously persistent red spot. Casey Dreier says the United States House of Representatives has proposed legislation that is at odds with NASA’s current Moon and Mars plans. John Flamsteed almost discovered Uranus! Bruce Betts will tell us where he went wrong in this week’s What’s Up space trivia contest.
Chinese officials marked the one-year anniversary of the Chang’e 4 mission’s historic first soft landing on the far side of the moon [January 3rd] with the public release of data collected by scientific instruments and cameras on the lunar lander and rover.
The Chang’e 4 lander and Yutu 2 rover landed together on the lunar surface Jan. 3, 2019, marking the first time a spacecraft has ever safely touched down on the far side of the moon.
Around 12 hours after touchdown, the Yutu 2 rover drove down a ramp to disembark from the Chang’e 4 mission’s stationary landing platform to begin exploring the barren lunar landscape.
Scientific instruments and cameras aboard the Chang’e 4 lander and Yutu 2 rover have downlinked measurements and numerous images in the past year. The Chang’e 4 mission relays data through a dedicated Chinese communications satellite positioned beyond the far side of the moon, with a line of sight to both Chang’e 4 and Earth-based receiving stations.
On Friday, the one-year anniversary of the mission’s successful landing, China National Space Administration and the Chinese Academy of Sciences published scientific data collected by five instruments on the Chang’e 4 lander and Yutu 2 rover.
After a year scoping out asteroid Bennu’s boulder-scattered surface, the team leading NASA’s first asteroid sample return mission has officially selected a sample collection site.
The Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-Rex) mission team concluded a site designated “Nightingale” – located in a crater high in Bennu’s northern hemisphere – is the best spot for the OSIRIS-REx spacecraft to snag its sample.
The OSIRIS-REx team spent the past several months evaluating close-range data from four candidate sites in order to identify the best option for the sample collection. The candidate sites – dubbed Sandpiper, Osprey, Kingfisher, and Nightingale – were chosen for investigation because, of all the potential sampling regions on Bennu, these areas pose the fewest hazards to the spacecraft’s safety while still providing the opportunity for great samples to be gathered.
Preliminary results indicate that NASA’s OSIRIS-REx spacecraft successfully executed a 0.4-mile (620-m) flyover of site Nightingale yesterday as part of the mission’s Reconnaissance B phase activities. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater high in asteroid Bennu’s northern hemisphere.
To perform the pass, the spacecraft left its 0.75-mile (1.2-km) safe home orbit and flew an almost 11-hour transit over the asteroid, aiming its science instruments toward the 52-ft (16-m) wide sample site before returning to orbit. Science observations from this flyover are the closest taken of a sample site to date.
The primary goal of the Nightingale flyover was to collect the high-resolution imagery required to complete the spacecraft’s Natural Feature Tracking image catalog, which will document the sample collection site’s surface features – such as boulders and craters. During the sampling event, which is scheduled for late August, the spacecraft will use this catalog to navigate with respect to Bennu’s surface features, allowing it to autonomously predict where on the sample site it will make contact . Several of the spacecraft’s other instruments also took observations of the Nightingale site during the flyover event, including the OSIRIS-REx Thermal Emissions Spectrometer (OTES), the OSIRIS-REx Visual and InfraRed Spectrometer (OVIRS), the OSIRIS-REx Laser Altimeter (OLA), and the MapCam color imager.
After making good progress in recent weeks, another day of digging on #Mars leads to the mole backing out by a couple of centimeters. My team keeps pushing forward and is exploring several options. pic.twitter.com/pe2eopDANi
The joint European/Russian ExoMars 2020 mission aims to launch on a Russian Proton rocket this summer and land on Mars on March 19, 2021. Problems with the parachutes need to be resolved else the mission will have to wait another two years for the next launch window: Promising progress for ExoMars parachutes – ESA