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(4 August 2020 – ALMA) All planets, including the ones in our Solar System, are born in disks of gas and dust around stars, so-called protoplanetary disks.

Thanks to ALMA we have stunning high-resolution images of many of these planet factories, showing dusty disks with multiple rings and gaps that hint to the presence of emerging planets. The most famous examples of these are HL Tau and TW Hydrae.

But disks are not necessarily as neatly arranged as these initial dust observations suggest. A new ALMA image of RU Lup, a young variable star in the Lupus constellation, revealed a giant set of spiral arms made of gas, extending far beyond its more well-known dust disk. This spiral structure – resembling a ‘mini-galaxy’ – extends to nearly 1000 astronomical units (au) from the star, much farther away than the compact dust disk that extends to about 60 au.

ALMA image of the planet-forming disk around the young star RU Lup. The inset image (lower left, red disk) shows a previous (DSHARP) observation of the dust disk with rings and gaps that hint at the presence of forming planets. The new observation shows a large spiral structure (in blue), made out of gas, that spans far beyond the compact dust disk, extending to nearly 1000 astronomical units from the star. (courtesy: ALMA (ESO/NAOJ/NRAO), J. Huang and S. Andrews; NRAO/AUI/NSF, S. Dagnello)

Previous observations of RU Lup with ALMA, which were part of the Disk Substructures at High Angular Resolution Project (DSHARP), already revealed signs of ongoing planet formation, hinted by the dust gaps in its protoplanetary disk. “But we also noticed some faint carbon monoxide (CO) gas structures that extended beyond the disk. That’s why we decided to observe the disk around the star again, this time focusing on the gas instead of the dust,” said Jane Huang of the Center for Astrophysics, Harvard & Smithsonian (CfA) and lead author on a paper published today in The Astrophysical Journal.

Protoplanetary disks contain much more gas than dust. While dust is needed to accumulate the cores of planets, gas creates their atmospheres.

In recent years, high resolution observations of dust structures have revolutionized our understanding of planet formation. However, this new image of the gas indicates that the current view of planet formation is still too simplistic and that it might be much more chaotic than previously inferred from the well-known images of neatly concentric ringed disks.

“The fact that we observed this spiral structure in the gas after a longer observation suggests that we have likely not seen the full diversity and complexity of planet-forming environments. We may have missed much of the gas structures in other disks,” added Huang.

Huang and her team suggest several scenarios that could possibly explain why the spiral arms appeared around RU Lup. Maybe the disk is collapsing under its own gravity, because it is so massive. Or maybe RU Lup is interacting with another star. Another possibility is that the disk is interacting with its environment, accreting interstellar material along the spiral arms.

“None of these scenarios completely explain what we have observed,” said team-member Sean Andrews of CfA. “There might be unknown processes happening during planet formation that we have not yet accounted for in our models. We will only learn what they are if we find other disks out there that look like RU Lup.”

Publication

This research is presented in a paper titled “Large-scale CO spiral arms and complex kinematics associated with the T Tauri star RU Lup”, by J. Huang et al., in The Astrophysical Journal.

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SwRI instruments aboard Rosetta help detect unexpected ultraviolet aurora at a comet

SwRI instruments aboard Rosetta help detect unexpected ultraviolet aurora at

(21 September 2020 – SwRI) Data from Southwest Research Institute-led instruments aboard ESA’s Rosetta spacecraft have helped reveal auroral emissions in the far ultraviolet around a comet for the first time.

At Earth, auroras are formed when charged particles from the Sun follow our planet’s magnetic field lines to the north and south poles. There, solar particles strike atoms and molecules in Earth’s atmosphere, creating shimmering curtains of colorful light in high-latitude skies. Similar phenomena have been seen at various planets and moons in our solar system and even around a distant star. SwRI’s instruments, the Alice far-ultraviolet (FUV) spectrograph and the Ion and Electron Sensor (IES), aided in detecting these novel phenomena at comet 67P/Churyumov-Gerasimenko (67P/C-G).

Data from Southwest Research Institute-led instruments aboard ESA’s Rosetta spacecraft helped reveal unique ultraviolet auroral emissions around irregularly shaped Comet 67P. Although these auroras are outside the visible spectra, other auroras have been seen at various planets and moons in our solar system and even around a distant star. (courtesy: ESA/Rosetta/NAVCAM)

“Charged particles from the Sun streaming towards the comet in the solar wind interact with the gas surrounding the comet’s icy, dusty nucleus and create the auroras,” said SwRI Vice President Dr. Jim Burch who leads IES. “The IES instrument detected the electrons that caused the aurora.”

The envelope of gas around 67P/C-G, called the “coma,” becomes excited by the solar particles and glows in ultraviolet light, an interaction detected by the Alice FUV instrument.

“Initially, we thought the ultraviolet emissions at comet 67P were phenomena known as ‘dayglow,’ a process caused by solar photons interacting with cometary gas,” said SwRI’s Dr. Joel Parker who leads the Alice spectrograph. “We were amazed to discover that the UV emissions are aurora, driven not by photons, but by electrons in the solar wind that break apart water and other molecules in the coma and have been accelerated in the comet’s nearby environment. The resulting excited atoms make this distinctive light.”

Dr. Marina Galand of Imperial College London led a team that used a physics-based model to integrate measurements made by various instruments aboard Rosetta.

“By doing this, we didn’t have to rely upon just a single dataset from one instrument,” said Galand, who is the lead author of a Nature Astronomy paper outlining this discovery. “Instead, we could draw together a large, multi-instrument dataset to get a better picture of what was going on. This enabled us to unambiguously identify how 67P/C-G’s ultraviolet atomic emissions form, and to reveal their auroral nature.”

“I’ve been studying the Earth’s auroras for five decades,” Burch said. “Finding auroras around 67P, which lacks a magnetic field, is surprising and fascinating.”

Following its rendezvous with 67P/C-G in 2014 through 2016, Rosetta has provided a wealth of data revealing how the Sun and solar wind interact with comets. In addition to discovering these cometary auroras, the spacecraft was the first to orbit a comet’s nucleus, the first to fly alongside a comet as it travelled into the inner Solar System and the first to send a lander to a comet’s surface.

Additional instruments contributing to this research were Rosetta’s Langmuir Probe (LAP), the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA), the Microwave Instrument for the Rosetta Orbiter (MIRO) and the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS).

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta’s Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI. Airbus Defense and Space built the Rosetta spacecraft. NASA’s Jet Propulsion Laboratory (JPL) manages the U.S. contribution of the Rosetta mission for NASA’s Science Mission Directorate in Washington, under a contract with the California Institute of Technology (Caltech). JPL also built the Microwave Instrument for the Rosetta Orbiter and hosts its principal investigator, Dr. Mark Hofstadter. SwRI (San Antonio and Boulder, Colorado) developed the Rosetta orbiter’s Ion and Electron Sensor and Alice instrument and hosts their principal investigators.

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Series C funding for ICEYE to continue conquering boundaries in radar satellite imaging

Series C funding for ICEYE to continue conquering boundaries in

(22 September 2020 – ICEYE) ICEYE today announced the closing of a larger than planned $87M Series C funding, led by return investor True Ventures, with a significant additional investment by OTB Ventures.

ICEYE has so far successfully launched 5 satellite missions, starting with the first ever small SAR satellite launched in January 2018. The company is launching 4 additional SAR satellites this year and is on course to launch at least an additional 8 in 2021. This will grow the existing operational constellation into a capability that is unique in the World. To date, ICEYE has raised a total of $152M in financing.

An artist’s depiction of two ICEYE SAR satellites in orbit. (courtesy: ICEYE)

“ICEYE is enabling others to solve immeasurably difficult problems that affect the lives of millions of people around the world. Our team has built a reputation of delivering results to our customers with unmatched timelines and quality of service. We are proud of that reputation, and we intend to maintain it,” said Rafal Modrzewski, CEO and Co-founder of ICEYE. “This round of investment ensures our SAR satellite constellation will reach a size of at least 12 satellites in 2021, guaranteeing 4 times a day revisit rate globally.”

ICEYE designs, manufactures and operates its SAR satellites in-house, with manufacturing timelines brought down to months for its spacecraft. Since the successful January 2018 launch of the first ICEYE SAR satellite, the company has delivered SAR imaging services and new capabilities to global customers. These years of operation have included many world-first achievements for small SAR satellites, such as 0.25 meter resolution data and SAR video. Recently, ICEYE has demonstrated record time data deliveries of 5 minutes from the start of data downlink to having processed images available on customer systems.

ICEYE intends to use this financing round to continue accelerating the growth of its SAR satellite constellation with more spacecraft, increasing data availability for all continents through 24/7 customer operations, continuing the development of ground-breaking radar imaging capabilities, and for establishing spacecraft manufacturing in the US. The financing round is significantly larger than originally planned, which is especially noteworthy during the economically turbulent year of 2020. It is a powerful sign of trust from the financial community that ICEYE’s business and operational model works, and that the organization is accelerating towards further global impact.

Given the unprecedented frequency and scale of climate driven changes in the weather, crop patterns, fires, urban living and human activities, there is a critical immediate need for real-time information and data access on a global scale. This access can be used for saving lives during humanitarian and disaster response situations, and for economic decision making during moments of crisis.

ICEYE has provided commercial radar satellite imaging worldwide for several years, enabling ICEYE’s customers to respond to oil spills, hurricanes, deforestation and many more use cases. Along with these active customer imaging operations, the ICEYE SAR satellite constellation has seen an unprecedented development cycle of new imaging capabilities and new spacecraft generations.

Adam Niewiński, co-founder and Managing Partner of OTB Ventures, said: “We are pleased to be a cornerstone investor in the latest round of venture funding for ICEYE. We are thrilled to be part of the evolving ecosystem where even the sky is no longer the limit.”

ICEYE’s Series C includes participation from return investors True Ventures, OTB Ventures, Finnish Industry Investment (Tesi), Draper Esprit, DNX Ventures, Draper Associates, Seraphim Capital, Promus Ventures and Space Angels. The funding round is joined by New Space Capital and Luxembourg Future Fund. The European Investment Fund (EIF) participated both as advisor to Luxembourg Future Fund and as investor through the InnovFin For Equity (IFE) programme, which is backed by the European Commission. Further, a significant portion of Tesi’s investment is supported by the European Investment Bank (EIB) under the European Fund for Strategic Investments (EFSI), the central pillar of the Investment Plan for Europe of the Juncker Commission. Coinciding with ICEYE’s Series C funding, OTB Ventures today announced the launch of a dedicated investment vehicle to support Europe’s leading space technologies – OTB Space Program I – backed by the European Investment Fund and the European Commission through the InnovFin for Equity programme.

About ICEYE

ICEYE is building and operating its own commercial constellation of radar imaging satellites, with SAR data available to global customers since 2018. With the company’s unique satellite constellation capabilities, ICEYE empowers others to make better decisions in governmental and commercial industries. The company is tackling a tremendous global need for timely and reliable information, with world-first aerospace capabilities and a New Space approach. ICEYE’s radar satellite imaging service, designed to deliver very frequent coverage, both day and night, helps clients resolve challenges in sectors such as maritime, disaster management, insurance, and finance.

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Meteorites from Vesta found on asteroid Bennu

Meteorites from Vesta found on asteroid Bennu

(21 September 2020 – NASA Goddard) It appears some pieces of asteroid Vesta ended up on asteroid Bennu, according to observations from NASA’s OSIRIS-REx spacecraft.

The new result sheds light on the intricate orbital dance of asteroids and on the violent origin of Bennu, which is a “rubble pile” asteroid that coalesced from the fragments of a massive collision.

“We found six boulders ranging in size from 5 to 14 feet (about 1.5 to 4.3 meters) scattered across Bennu’s southern hemisphere and near the equator,” said Daniella DellaGiustina of the Lunar & Planetary Laboratory, University of Arizona, Tucson. “These boulders are much brighter than the rest of Bennu and match material from Vesta.”

During spring 2019, NASA’s OSIRIS-REx spacecraft captured these images, which show fragments of asteroid Vesta present on asteroid Bennu’s surface. The bright boulders (circled in the images) are pyroxene-rich material from Vesta. Some bright material appear to be individual rocks (left) while others appear to be clasts within larger boulders (right). (courtesy: NASA/Goddard/University of Arizona)

“Our leading hypothesis is that Bennu inherited this material from its parent asteroid after a vestoid (a fragment from Vesta) struck the parent,” said Hannah Kaplan of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Then, when the parent asteroid was catastrophically disrupted, a portion of its debris accumulated under its own gravity into Bennu, including some of the pyroxene from Vesta.”

DellaGiustina and Kaplan are primary authors of a paper on this research appearing in Nature Astronomy September 21.

The unusual boulders on Bennu first caught the team’s eye in images from the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) Camera Suite (OCAMS). They appeared extremely bright, with some almost ten times brighter than their surroundings. They analyzed the light from the boulders using the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) instrument to get clues to their composition. A spectrometer separates light into its component colors. Since elements and compounds have distinct, signature patterns of bright and dark across a range of colors, they can be identified using a spectrometer. The signature from the boulders was characteristic of the mineral pyroxene, similar to what is seen on Vesta and the vestoids, smaller asteroids that are fragments blasted from Vesta when it sustained significant asteroid impacts.

Of course it’s possible that the boulders actually formed on Bennu’s parent asteroid, but the team thinks this is unlikely based on how pyroxene typically forms. The mineral typically forms when rocky material melts at high-temperature. However, most of Bennu is composed of rocks containing water-bearing minerals, so it (and its parent) couldn’t have experienced very high temperatures. Next, the team considered localized heating, perhaps from an impact. An impact needed to melt enough material to create large pyroxene boulders would be so significant that it would have destroyed Bennu’s parent-body. So, the team ruled out these scenarios, and instead considered other pyroxene-rich asteroids that might have implanted this material to Bennu or its parent.

Observations reveal it’s not unusual for an asteroid to have material from another asteroid splashed across its surface. Examples include dark material on crater walls seen by the Dawn spacecraft at Vesta, a black boulder seen by the Hayabusa spacecraft on Itokawa, and very recently, material from S-type asteroids observed by Hayabusa2 at Ryugu. This indicates many asteroids are participating in a complex orbital dance that sometimes results in cosmic mashups.

As asteroids move through the solar system, their orbits can be altered in many ways, including the pull of gravity from planets and other objects, meteoroid impacts, and even the slight pressure from sunlight. The new result helps pin down the complex journey Bennu and other asteroids have traced through the solar system.

Based on its orbit, several studies indicate Bennu was delivered from the inner region of the Main Asteroid Belt via a well-known gravitational pathway that can take objects from the inner Main Belt to near-Earth orbits. There are two inner Main Belt asteroid families (Polana and Eulalia) that look like Bennu: dark and rich in carbon, making them likely candidates for Bennu’s parent. Likewise, the formation of the vestoids is tied to the formation of the Veneneia and Rheasilvia impact basins on Vesta, at roughly about two billion years ago and approximately one billion years ago, respectively.

“Future studies of asteroid families, as well as the origin of Bennu, must reconcile the presence of Vesta-like material as well as the apparent lack of other asteroid types. We look forward to the returned sample, which hopefully contains pieces of these intriguing rock types,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. “This constraint is even more compelling given the finding of S-type material on asteroid Ryugu. This difference shows the value in studying multiple asteroids across the solar system.”

The spacecraft is going to make its first attempt to sample Bennu in October and return it to Earth in 2023 for detailed analysis. The mission team closely examined four potential sample sites on Bennu to determine their safety and science value before making a final selection in December 2019. DellaGiustina and Kaplan’s team thinks they might find smaller pieces of Vesta in images from these close-up studies.

The research was funded by the NASA New Frontiers Program. The primary authors acknowledge significant collaboration with the French space agency CNES and Japan Society for the Promotion of Science Core-to-core Program on this paper. NASA’s Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. The late Michael Drake of the University of Arizona pioneered the study of vestoid meteorites and was the first principal investigator for OSIRIS-REx. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. NASA is exploring our Solar System and beyond, uncovering worlds, stars, and cosmic mysteries near and far with our powerful fleet of space and ground-based missions.

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