Category Archives: Astronomy

ESO: VLT sees evidence of a planet forming in disc of dust and gas around star AB Aurigae

The latest news from ESO (European Southern Observatory):

ESO Telescope Sees Signs of Planet Birth
The Twist Marks the Spot

This image shows the disc around the young AB Aurigae star, where ESO’s Very Large Telescope (VLT) has spotted signs of planet birth. Close to the centre of the image, in the inner region of the disc, we see the ‘twist’ (in very bright yellow) that scientists believe marks the spot where a planet is forming. This twist lies at about the same distance from the AB Aurigae star as Neptune from the Sun.
The image was obtained with the VLT’s SPHERE instrument in polarised light.

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.

The images of the AB Aurigae system showing the disc around it. The image on the right is a zoomed-in version of the area indicated by a red square on the image on the left. It shows the inner region of the disc, including the very-bright-yellow ‘twist’ (circled in white) that scientists believe marks the spot where a planet is forming. This twist lies at about the same distance from the AB Aurigae star as Neptune from the Sun. The blue circle represents the size of the orbit of Neptune. The images were obtained with the SPHERE instrument on ESO’s Very Large Telescope in polarised light.

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,”

he concludes.

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Fire in the Sky:
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Carnivals of Space #658-661 – Urban Astronomer & Universe Today

The Urban Astronomer hosted a combined Carnivals of Space #658-659.

Artist’s rendering of a supermassive black hole formed in early universe. Credits: SISSA via Carnival of Space and Universe Today.

And Universe Today hosted the Carnivals of Space #660-661.

First image of a black hole. Credits: Event Horizon Telescope Collaboration via Carnival of Space and Chandra Observatory.

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More Things in the Heavens:
How Infrared Astronomy Is Expanding Our View of the Universe

ESO: Black hole found in triple star system just 1000 light years away

The latest report from ESO (European Southern Observatory):

ESO Instrument Finds Closest Black Hole to Earth
Invisible object has two companion stars visible to the naked eye

This artist’s impression shows the orbits of the objects in the HR 6819 triple system. This system is made up of an inner binary with one star (orbit in blue) and a newly discovered black hole (orbit in red), as well as a third star in a wider orbit (also in blue). The team originally believed there were only two objects, the two stars, in the system. However, as they analysed their observations, they were stunned when they revealed a third, previously undiscovered body in HR 6819: a black hole, the closest ever found to Earth. The black hole is invisible, but it makes its presence known by its gravitational pull, which forces the luminous inner star into an orbit. The objects in this inner pair have roughly the same mass and circular orbits. The observations, with the FEROS spectrograph on the 2.2-metre telescope at ESO’s La Silla, showed that the inner visible star orbits the black hole every 40 days, while the second star is at a large distance from this inner pair.

A team of astronomers from the European Southern Observatory (ESO) and other institutes has discovered a black hole lying just 1000 light-years from Earth. The black hole is closer to our Solar System than any other found to date and forms part of a triple system that can be seen with the naked eye. The team found evidence for the invisible object by tracking its two companion stars using the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. They say this system could just be the tip of the iceberg, as many more similar black holes could be found in the future.

“We were totally surprised when we realised that this is the first stellar system with a black hole that can be seen with the unaided eye,”

says Petr Hadrava, Emeritus Scientist at the Academy of Sciences of the Czech Republic in Prague and co-author of the research. Located in the constellation of Telescopium, the system is so close to us that its stars can be viewed from the southern hemisphere on a dark, clear night without binoculars or a telescope.

“This system contains the nearest black hole to Earth that we know of,”

says ESO scientist Thomas Rivinius, who led the study published today in Astronomy & Astrophysics.

The team originally observed the system, called HR 6819, as part of a study of double-star systems. However, as they analysed their observations, they were stunned when they revealed a third, previously undiscovered body in HR 6819: a black hole. The observations with the FEROS spectrograph on the MPG/ESO 2.2-metre telescope at La Silla showed that one of the two visible stars orbits an unseen object every 40 days, while the second star is at a large distance from this inner pair.

Dietrich Baade, Emeritus Astronomer at ESO in Garching and co-author of the study, says:

“The observations needed to determine the period of 40 days had to be spread over several months. This was only possible thanks to ESO’s pioneering service-observing scheme under which observations are made by ESO staff on behalf of the scientists needing them.”

This animation shows the orbits and movements of the objects in the HR 6819 triple system. This system includes an inner binary with one star (orbit indicated in blue) and a newly discovered black hole (orbit indicated in red). As we move away from this inner pair, we see the outer object in the system, another star in a much wider orbit (in blue). 

The team originally believed there were only two objects, the two stars, in the system. However, as they analysed their observations, they were stunned when they revealed a third, previously undiscovered body in HR 6819: a black hole, the closest ever found to Earth. The black hole is invisible, but it makes its presence known by its gravitational pull, which forces the luminous inner star into an orbit. The objects in this inner pair have roughly the same mass and circular orbits.

The observations, with the FEROS spectrograph on the 2.2-metre telescope at La Silla, showed that the inner visible star orbits the black hole every 40 days, while the second star is at a large distance from this inner pair. 

The hidden black hole in HR 6819 is one of the very first stellar-mass black holes found that do not interact violently with their environment and, therefore, appear truly black. But the team could spot its presence and calculate its mass by studying the orbit of the star in the inner pair.

“An invisible object with a mass at least 4 times that of the Sun can only be a black hole,”

concludes Rivinius, who is based in Chile.

Astronomers have spotted only a couple of dozen black holes in our galaxy to date, nearly all of which strongly interact with their environment and make their presence known by releasing powerful X-rays in this interaction. But scientists estimate that, over the Milky Way’s lifetime, many more stars collapsed into black holes as they ended their lives. The discovery of a silent, invisible black hole in HR 6819 provides clues about where the many hidden black holes in the Milky Way might be.

“There must be hundreds of millions of black holes out there, but we know about only very few. Knowing what to look for should put us in a better position to find them,” says Rivinius. Baade adds that finding a black hole in a triple system so close by indicates that we are seeing just “the tip of an exciting iceberg.”

Already, astronomers believe their discovery could shine some light on a second system.

“We realised that another system, called LB-1, may also be such a triple, though we’d need more observations to say for sure,” says Marianne Heida, a postdoctoral fellow at ESO and co-author of the paper. “LB-1 is a bit further away from Earth but still pretty close in astronomical terms, so that means that probably many more of these systems exist. By finding and studying them we can learn a lot about the formation and evolution of those rare stars that begin their lives with more than about 8 times the mass of the Sun and end them in a supernova explosion that leaves behind a black hole.”

The discoveries of these triple systems with an inner pair and a distant star could also provide clues about the violent cosmic mergers that release gravitational waves powerful enough to be detected on Earth. Some astronomers believe that the mergers can happen in systems with a similar configuration to HR 6819 or LB-1, but where the inner pair is made up of two black holes or of a black hole and a neutron star. The distant outer object can gravitationally impact the inner pair in such a way that it triggers a merger and the release of gravitational waves. Although HR 6819 and LB-1 have only one black hole and no neutron stars, these systems could help scientists understand how stellar collisions can happen in triple star systems.

This wide-field view shows the region of the sky, in the constellation of Telescopium, where HR 6819 can be found, a triple system consisting of two stars and the closest black hole to Earth ever found. This view was created from images forming part of the Digitized Sky Survey 2. While the black hole is invisible, the two stars in HR 6819 can be viewed from the southern hemisphere on a dark, clear night without binoculars or a telescope.

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Videos: Night sky highlights for May 2020

[ Update 2: What’s Up: May 2020 – Skywatching Tips from NASA JPL

What astronomy highlights can you see in the sky in May 2020? Venus, Sirius and the Milky Way. With so many of us staying home these days, here’s a look into the sky at dusk and dawn with an eye toward the vast stretches of wide open space right above our heads. Additional information about topics covered in this episode of What’s Up, along with still images from the video, and the video transcript, are available at https://solarsystem.nasa.gov/whats-up… Credit: NASA/JPL-Caltech

UpdateSkywatch: What’s happening in the heavens in May – The Washington Post.

]

** Tonight’s Sky: Space Telescope Science Institute – YouTube

In May, we are looking away from the crowded, dusty plane of our own galaxy toward a region where the sky is brimming with distant galaxies. Locate Virgo to find a concentration of roughly 2,000 galaxies and search for Coma Berenices to identify many more. Keep watching for space-based views of galaxies like the Sombrero Galaxy, M87, and M64.

** What’s in the Night Sky May 2020Alyn Wallace – YouTube

** What to see in the night sky: May 2020BBC Sky at Night Magazine – YouTube

Pete Lawrence and Paul Abel guide us through May’s stargazing highlights.

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NIAC project aims to image exoplanets with solar gravity lens system enabled by advanced solar sail

Xplore sent me this press release:

NASA $2M Grant Advances Study to Directly Image Exoplanets Light Years Away
Xplore’s Advanced Solar Sail Design will be the Fastest Spacecraft Ever Made,
Expanding Xplore’s Reach Beyond the Inner Solar System

Xplore Inc., a commercial space exploration company providing Space as a Service™ today announced they and their teammates won a NASA Innovative Advanced Concepts (NIAC) Phase III award for a two-year, $2M NASA grant to further mature the Solar Gravity Lens Focus (SGLF) architecture to image planets in orbit around distant stars starting with a Technology Demonstration Mission (TDM). Dr. Slava G. Turyshev, a NIAC Fellow and Senior Research Scientist at NASA’s Jet Propulsion Laboratory (JPL) is the Principal Investigator leading the SGLF mission which includes Xplore, JPL and The Aerospace Corporation. The SGLF mission study is only the third Phase III award granted in the NIAC program ever.

Xplore’s Advanced Solar Sail for NASA’s Solar Gravity Lens Focus Mission, visualization by Bryan Versteeg, SpaceHabs.com

Reaching the focus region where the Sun’s gravity acts like a magnifying lens to the background sky is an immense technological challenge. This region, the SGLF, is over 500 times the distance between Earth and the Sun (547 AU). One Astonomical Unit (AU) is the distance from Earth to the Sun, about 93 million miles (149.5 million km). Even by using our fastest deep space probe, Voyager 1, moving at 11 miles/s (17 km/s) it will take over 150 years to reach just the edge of the SGLF region.

During the previous two NIAC phases nearly every credible propulsion technology was assessed to not only accurately navigate across this vast distance, but also to communicate and operate once at the SGLF — all within a goal of 25 years from launch. To reach the SGLF on a timescale of 25 years requires a propulsion system capable of accelerating a spacecraft to a speed seven times faster than Voyager 1 (> 20 AU/yr or 100 km/s). The resulting propulsion technology was found to meet both the high speed requirement and the proposed architecture of sending many vehicles to the SGLF. This propulsion does not exploit chemical or nuclear reactions, but simply harnesses sunlight reflecting from a solar sail.

As a key enabler for the SGLF mission, Xplore will design the spacecraft for the SGLF’s Technology Demonstration Mission (TDM). The TDM vehicle as pictured is an advanced solar sail design based upon L’Garde’s SunVane concept. The SunVane concept addresses the control, packaging and scalability challenges of traditional large planar solar sails by breaking up the required overall sail area into smaller rotatable vanes distributed across a lightweight truss. Xplore will transition this concept to a prototype design as a first step toward demonstrating the key technologies necessary to achieve the SGLF mission. The goal for the Xplore TDM vehicle using current technologies is to reach speeds in excess of two to three times that of Voyager 1 (5-8 AU/year). At these unprecedented speeds it would allow the TDM vehicle to reach Jupiter in less than a year and Saturn in two years.

Xplore Founder Lisa Rich said,

“Xplore is laying the groundwork to revolutionize the transit speed to destinations in our solar system, and beyond. Once Xplore completes the design, build and first flight of the TDM vehicle, the company would accelerate these missions — perhaps sending one per year, to rapidly advance solar system exploration while providing fast reaction options for flybys of newly-discovered interstellar objects like Oumuamua and high energy intercepts for planetary defense.”

The TDM will enable rapid transit to dramatically transform and ease the exploration of the outer solar system and Kuiper belt objects. At 5-8 AU per year, the TDM vehicle’s extraordinary speed will allow it to reach Voyager in 20 years. To put these distances into perspective, New Horizons launched in 2006 and thirteen years later performed the first flyby of Ultima Thule, a distant Kuiper Belt object that lies 1 billion miles (1.6 billion km) beyond Pluto.

Alan Stern, planetary scientist, Associate Vice President of the Southwest Research Institute and the Principal Investigator on New Horizons mission to Pluto said,

“This is an incredible mission with incredible technology. I am incredibly excited to see it selected for study by NIAC. SGLF offers to revolutionize both exoplanet science and propulsion technology if implemented.”

The design of the TDM spacecraft is led by Xplore Founder and Chief Technology Officer, Dr. Darren Garber, who helped develop L’Garde’s SunVane concept and provided operational support to LightSail. Dr. Garber will coordinate with JPL and Aerospace team members to ensure that the TDM vehicle’s design and future flight will represent the next step toward traversing 500 AU in 25 years or less.

Dr. Louis D. Friedman, Xplore Advisor and Co-Founder of The Planetary Society, worked on numerous flagship missions including Mariner, Voyager, Magellan and the Mars Program. A well-known champion of the Halley’s Comet Rendezvous-Solar Sail project back in the 70s with Dr. Carl Sagan, Dr. Friedman said,

“I’m proud that Xplore, led by our colleague Dr. Slava Turyshev, will advance the vision for space exploration Carl Sagan and I put in motion many years ago. The ability to harness the power of the Sun to rapidly transit to distant corners of our universe is a groundbreaking effort that will impact the science community for generations.”

Xplore’s team is comprised entirely of experienced U.S. space professionals who have supported all aspects of the design, development and operations of advanced technology missions for commercial, civil and national security space customers.

For the TDM, Dr. Garber and Xplore’s advanced engineering team will leverage key components, software and system engineering processes employed for its Xcraft™, a high-performance, ESPA-class, multi-mission spacecraft uniquely designed for missions in the inner solar system with a planned lunar radar mapping mission in early 2022. Their expertise will further define the SGLF Phase III study mission and architecture analysis such as using clusters of follow-on TDM vehicles to collectively mitigate risk and lower total system cost. Multiple mass-produced TDM spacecraft offer resiliency and scalability for a future decades-long mission, and the concept could allow other partners to contribute their own set of clustered spacecraft to cooperatively operate during the journey to the solar gravitational lens region in deep space.

Solar Gravity Lens Concept Receives $2M NASA Grant for Technology Maturation.
Aerospace Corp.

Lisa Rich said,

“Designing the fastest object ever made in the history of humanity is a challenge worthy of the legacy of Carl Sagan, and we look forward to advancing solar sail technologies with our Advisor, Dr. Lou Friedman. SGLF aligns with Xplore’s long-term vision for frequent, low-cost commercial missions to deep space. The ability to rapidly travel anywhere in the solar system expands our human footprint and will open up new avenues for scientific exploration.”

About Xplore Inc.: Xplore is a Seattle-based company offering Space as a Service™. Xplore provides hosted payloads, communication relay services and exclusive datasets to its customers via the Xcraft™, the company’s multi-mission spacecraft. Xplore’s mission is to expand robotic exploration via commercial missions at and beyond Earth, to the Moon, Mars, Venus, Lagrange points and near-Earth asteroids for national space agencies, national security agencies, sovereign space agencies and universities.

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