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Two images showing swirls and eddies in the atmospheres of a hot jupiter; the left represents the planet's nightside, and the right represents the planet's dayside.

Hot Jupiters are giant exoplanets that orbit very close to their host stars, generally in a 1:1 spin–orbit ratio that ensures they always present the same face to their host. How does the atmosphere of a hot Jupiter respond to the bombardment of radiation on only one side of the planet? In a new study led by James Cho (CCA, Flatiron Institute), a team of scientists has conducted detailed simulations to find out. The delicate vorticity maps above (click for a closer look) show the nightside (left) and dayside (right) of a simulated hot Jupiter atmosphere. Cho and collaborators’ high-resolution simulations are designed to accurately capture small-scale eddies and waves that arise in the atmosphere as the unequal heating drives flows. The authors show that intense storms result across the hot Jupiter on both small and large scales, leading to global variability and chaotic mixture of the atmosphere. To learn more about the authors’ results, check out the original article below.

Citation

“Storms, Variability, and Multiple Equilibria on Hot Jupiters,” James Y-K. Cho et al 2021 ApJL 913 L32. doi:10.3847/2041-8213/abfd37

Photograph of the Sun during an eclipse reveals large-scale stalks extending through the sun's corona. Two are labeled "streamer" and one is labeled "pseudostreamer".

This stunning image of the Sun during a total solar eclipse, included in today’s article with permission from astrophotographer Nicolas Lefaudeux, illustrates an intriguing structure in the solar corona: a pseudostreamer. Streamers and pseudostreamers structure the Sun’s outer atmosphere — the corona — on enormous scales. True streamers, which are long-lived and relate to the global dipole magnetic field of the Sun, separate regions of opposite magnetic field in the corona. Pseudostreamers, on the other hand, are transient structures that separate regions of the same polarity. Can you tell which is which in the image above? Click on the image to see the labels. A team of scientists led by Roger Scott (US Naval Research Laboratory) has now created the first detailed 3D numerical simulations of the formation of a pseudostreamer and explored the implications for the origins of the extremely variable slow solar wind, a stream of magnetized particles that flows from the Sun. To learn more about the team’s results, check out the original article below.

Citation

“The Dynamic Formation of Pseudostreamers,” Roger B. Scott et al 2021 ApJ 913 64. doi:10.3847/1538-4357/abec4f

Six panels show different magnetic field line configurations where reconnection may occur.

Magnetic reconnection — when magnetic fields rearrange themselves, breaking neighboring field lines and rejoining them in a new configuration — is a critical process in astrophysical plasmas. This rearrangement converts energy stored in the magnetic fields into kinetic and thermal energy, playing a major role in phenomena like solar flares or the Earth’s aurora. But reconnection is not yet well understood — especially when operating in three dimensions! In particular, it’s notoriously difficult to identify the sites where reconnection occurs in 3D. In a recent study, scientist Giovanni Lapenta (Space Science Institute; KU Leuven University, Belgium) presents a new indicator that can be used to detect reconnection sites in both observations and simulations of 3D plasmas. The images above, adapted from figures in the study, show the magnetic field configurations for six different probable reconnection sites identified via Lapenta’s process in a 3D simulation of a turbulent outflow. To learn more, check out the original article below.

Citation

“Detecting Reconnection Sites Using the Lorentz Transformations for Electromagnetic Fields,” Giovanni Lapenta 2021 ApJ 911 147. doi:10.3847/1538-4357/abeb74

Compilation of 12 images of the sun taken during a solar eclipse, so the extended solar corona and streams of solar wind are visible.

The figure above (click for the full view) contains 6 pairs of images of the Sun captured during different total solar eclipses between 2008 and 2020. During an eclipse, the Moon blocks the bright light of the solar disk and reveals the complex structure of the Sun’s corona. Each beautifully detailed pair of images above shows a white-light picture (left), and an overlay of white light with Fe XI 789.2 nm (red) and Fe XIV 530.3 nm (green) emission (right). A team of scientists led by Shadia Habbal (Institute for Astronomy, University of Hawaii) has used these images and complementary in situ observations from NASA’s Advanced Composition Explorer — a spacecraft that measures the properties of solar wind particles — to explore the source regions of different solar wind streams. By studying where solar wind streams arise, the authors are able to better understand the physical processes that shape these flows of energetic particles from our host star. To learn more about their work (and to see more spectacular images!), check out the article below.

Citation

“Identifying the Coronal Source Regions of Solar Wind Streams from Total Solar Eclipse Observations and in situ Measurements Extending over a Solar Cycle,” Shadia R. Habbal et al 2021 ApJL 911 L4. doi:10.3847/2041-8213/abe775

Photograph of radio emission from a jet composited with a cluster of bright galaxies.

This stunning composite image (click for the full view!) reveals the radio emission (shown in red) from a bent jet that was launched from the galaxy NGC 1272, the bright source just to the right of the image center. The 12’ x 12’ image of the Perseus galaxy cluster is captured by the Sloan Digital Sky Survey; the brightest central galaxy of the cluster, NGC 1275, can be seen to NGC 1272’s left. A new publication led by Marie-Lou Gendron-Marsolais (European Southern Observatory) presents high-resolution Very Large Array images of the detailed radio structures in the Perseus cluster. The authors use these new data to study how the galaxy’s movement as it falls into the cluster, as well as the bulk motions of the intracluster gas, shape the powerful radio jet into the dramatic shapes we see here. For more information, check out the original article below.

Citation

“VLA Resolves Unexpected Radio Structures in the Perseus Cluster of Galaxies,” M.-L. Gendron-Marsolais et al 2021 ApJ 911 56. doi:10.3847/1538-4357/abddbb

mosaic of small images of newly discovered gravitational lens systems

You’re looking at just a handful (click here to see a few more!) of the 1,210 strong gravitational lens candidates newly discovered in a recent study that analyzed data from the Dark Energy Spectroscopic Instrument (DESI) Legacy Surveys. Strong gravitational lensing occurs when light from a background source bends around a massive foreground object (like a galaxy). This bending smears the light from the background source into arcs, rings, and multiple images. In a study led by Xiaosheng Huang (University of San Francisco), scientists have now used trained neural networks to search the DESI data for new strong gravitational lensing systems, finding a treasure trove of candidates. The new discoveries dramatically extend our set of known strong lens systems — in 2018, when the first iteration of this project began, there were only a few hundred confirmed strong lenses. To read more about the project and its results, check out the original article below.

Citation

“Discovering New Strong Gravitational Lenses in the DESI Legacy Imaging Surveys,” X. Huang et al 2021 ApJ 909 27. doi:10.3847/1538-4357/abd62b

Diagram illustrating formation of icy exomoons in the radiation belt surrounding a giant planet.

This schematic shows one possible solution to an intriguing white-dwarf mystery, in which two white dwarfs have been observed to contain an overabundance of the rare element beryllium. Unlike many heavy elements, beryllium isn’t formed in stars; instead, it’s produced by spallation, in which larger atomic nuclei break up after being bombarded by high-energy protons. So how did this unexpected element end up in the atmospheres of white dwarfs? A new publication led by Alexandra Doyle (UC Los Angeles) proposes a path: white dwarfs may become polluted by beryllium after accreting the icy exomoons of giant planets orbiting the dwarf. If these exomoons formed within the radiation belts of their planets, their composition could include spallogenic nuclides like beryllium. When the moons accrete onto the white dwarf, that beryllium then pollutes the white dwarf’s atmosphere. Doyle and collaborators illustrate the extreme environment in which these beryllium-enriched ices form in the image above. To learn more, check out the original article below.

Citation

“Icy Exomoons Evidenced by Spallogenic Nuclides in Polluted White Dwarfs,” Alexandra E. Doyle et al 2021 ApJL 907 L35. doi:10.3847/2041-8213/abd9ba

Two photographs of the Stingray Nebula taken in 1996 and 2016. The more recent one shows a much dimmer, less crisp, smaller nebula.

These two Hubble Space Telescope images of the Stingray Nebula (click to enlarge), spaced 20 years apart, show the remarkably rapid evolution of this unique planetary nebula. Planetary nebulae are formed when the outer layers of a dying intermediate-mass star are expelled and subsequently ionized by radiation from the star’s hot core. This ionized gas then glows until it eventually recombines and fades. While typical planetary nebulae arise and decline on timescales of thousands of years, observations of the Stingray Nebula show this same evolution occurring over about 40 years — it first became visibly ionized in the 1980s, and it has already dramatically faded and changed shape, structure, and size. It will likely be barely detectable within a couple decades. The Hubble observations showing the rapid changes in this youngest known planetary nebula are reported on in a new publication led by Bruce Balick (University of Washington).

Citation

“The Decline and Fall of the Youngest Planetary Nebula,” Bruce Balick et al 2021 ApJ 907 104. doi:10.3847/1538-4357/abcc61

Direct image of a bright, blue swirl of material forming a spiral disk with long streamers.

You’re looking at a photograph of a swirling disk of gas and dust that surrounds a star more than 500 light-years away. This stunning image (click for the full view!) of SU Aurigae’s circumstellar disk was brought to you by the ESO Very Large Telescope’s SPHERE instrument, which is working to capture up-close looks at planetary birthplaces like this one as part of the DESTINYS program. The results for SU Aur are presented in a recent publication led by Christian Ginski (University of Amsterdam and Leiden Observatory, the Netherlands). Here, the disk of SU Aur is resolved down to scales of just ~7 au, showing the extended dust structures around the young star in unprecedented detail. The image reveals the spiral structure of the disk and a shadow lane cast by an inner, misaligned disk component. These observations provide evidence that accretion can shape the disks around stars even in later stages of a star’s formation, possibly leading to planetary systems that have their spins and orbits misaligned. For more information, check out the annotated image and the authors’ original article below.

annotated version of the cover image marks the shadowed region and tails of dust.

Annotated VLT/SPHERE image of SU Aur. [Ginski et al. 2021]

Citation

“Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Late Infall Causing Disk Misalignment and Dynamic Structures in SU Aur,” Christian Ginski et al 2021 ApJL 908 L25. doi:10.3847/2041-8213/abdf57

Two plots, one with a wireframe model overlaid, show a white-light image of a coronal mass ejection erupting from the sun.

Learning about enormous solar explosions requires both observations that span the electromagnetic spectrum and careful modeling. The figure above shows a white-light image taken during a radio burst that was accompanied by a coronal mass ejection — a rapid release of plasma and radiation from the Sun’s outer atmosphere — in 2015. A new study led by Sherry Chhabra (New Jersey Institute of Technology and NASA Goddard SFC) presents long-wavelength radio images of this burst captured with the Owens Valley Radio Observatory. The team then uses the radio observations and white-light images from SOHO/LASCO to reconstruct the coronal mass ejection as it is released from the Sun; the model is shown above in the right panel as the green wireframe overlaid on the LASCO image (which is roughly 3° x 3°). The combined information about this burst tells us more about its properties and emission mechanisms, helping us to understand how energy is released from the Sun. For more information, check out the original article below.

8 panel plot showing 4 stages of eruption in both white light and radio light.

The different stages of eruption can be seen from left to right in these white-light (top) and radio (contours and bottom) images tracking the radio burst and associated CME. [Chhabra et al. 2020]

Citation

“Imaging Spectroscopy of CME-associated Solar Radio Bursts using OVRO-LWA,” Sherry Chhabra et al 2021 ApJ 906 132. doi:10.3847/1538-4357/abc94b

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