The X-shaped bulge is even more evident in this image, wherein a simple exponential disk model has been subtracted off. [Adapted from Ness & Lang 2016]
Melissa Ness and Dustin Lang 2016 AJ 152 14. doi:10.3847/0004-6256/152/1/14
An image of GG Tau, a quadruple system, from the Gemini North telescope in Hawaii. The two white stars each mark a binary system; the bottom star marks the binary GG Tau A. [Daniel Potter/University of Hawaii Adaptive Optics Group/Gemini Observatory/AURA/NSF]
Andrew F. Nelson and F. Marzari 2016 ApJ 827 93. doi:10.3847/0004-637X/827/2/93
This beautiful 13’ x 13’ image (click for the full view!) holds more than meets the eye. Look closely at the small concentration of blue stars just to the left of center. This is Eridanus II, one of nine new ultra-faint galaxies discovered just last year around the Milky Way. Detected as part of the Dark Energy Survey (DES) and presented in a study led by Sergey E. Koposov (Institute of Astronomy, Cambridge), these new galaxies add to a growing list of very dim satellites that orbit within the Milky Way’s potential. Since their discovery, these DES satellites have been used to answer a number of astronomical questions. In particular, the large dark-matter fraction of these ultra-faint galaxies makes them excellent laboratories for testing models of dark matter in the universe. Check back with us on Wednesday to learn more about what Eridanus II has revealed about dark matter! And for more information on the nine DES-discovered ultra-faint satellites, check out the paper below.
Sergey E. Koposov et al 2015 ApJ 805 130. doi:10.1088/0004-637X/805/2/130
These vibrant images (click for the full view!) of supernova remnants in the Large Magellanic Cloud (LMC) were created by mapping data from the Chandra X-ray Telescope into three colors: red for 300–720 eV, green for 720–1100 eV, and blue for 1100–7000 eV. Three scientists at University of Texas at Arlington — Andrew Schenck, Sangwook Park, and Seth Post — created these maps in order to probe the composition of the LMC’s interstellar medium. The forward shocks of supernova remnants sweep up the interstellar medium as they expand, heating it and causing it to emit the X-rays that Chandra observes. Schenck, Park and Post used Chandra’s observations of these remnants to make new measurements of the interstellar metallicities in the LMC. To find out more, check out the paper below!
Andrew Schenck et al 2016 AJ 151 161. doi:10.3847/0004-6256/151/6/161
![Zonal wind profile for Jupiter, describing the speed and direction of its winds at each latitude. [Simon et al. 2015]](https://aasnova.org/wp-content/uploads/2016/07/fig2.jpg)
Zonal wind profile for Jupiter, describing the speed and direction of its winds at each latitude. [Simon et al. 2015]
In contrast to this study, the Juno mission (which will be captured into Jupiter’s orbit today after a 5-year journey to Jupiter!) will be focusing more on the features below Jupiter’s surface, studying its deep atmosphere and winds. Some of Juno’s primary goals are to learn about Jupiter’s composition, gravitational field, magnetic field, and polar magnetosphere. You can follow along with the NASATV livestream as Juno arrives at Jupiter tonight; orbit insertion coverage starts at 10:30 EDT.
Amy A. Simon et al 2015 ApJ 812 55. doi:10.1088/0004-637X/812/1/55
This beautiful mosaic of images of the Whirlpool galaxy (M51) and its companion was taken with the Advanced Camera for Surveys on the Hubble Space Telescope. This nearby, “grand-design spiral” galaxy has a rich population of star clusters, making it both a stunning target for imagery and an excellent resource for learning about stellar formation and evolution. In a recent study, Rupali Chandar (University of Toledo) and collaborators cataloged over 3,800 compact star clusters within this galaxy. They then used this catalog to determine the distributions for the clusters’ ages, masses, and sizes, which can provide important clues as to how star clusters form, evolve, and are eventually disrupted. You can read more about their study and what they discovered in the paper below.
Rupali Chandar et al 2016 ApJ 824 71. doi:10.3847/0004-637X/824/2/71
This image of a fireball was captured in the Czech Republic by cameras at a digital autonomous observatory in the village of Kunžak. This observatory is part of a network of stations known as the European Fireball Network, and this particular meteoroid detection, labeled EN130114, is notable because it has the lowest initial velocity of any natural object ever observed by the network. Led by David Clark (University of Western Ontario), the authors of a recent study speculate that before this meteoroid impacted Earth, it may have been a Temporarily Captured Orbiter (TCO). TCOs are near-Earth objects that make a few orbits of Earth before returning to heliocentric orbits. Only one has ever been observed to date, and though they are thought to make up 0.1% of all meteoroids, EN130114 is the first event ever detected that exhibits conclusive behavior of a TCO. For more information on EN130114 and why TCOs are important to study, check out the paper below!
David L. Clark et al 2016 AJ 151 135. doi:10.3847/0004-6256/151/6/135
This remarkable false-color, mid-infrared image (click for the full view!) was produced by the Wide-field Infrared Survey Explorer (WISE). It captures a tantalizing view of Sh 2-207 and Sh 2-208, the latter of which is one of the lowest-metallicity star-forming regions in the Galaxy. In a recent study led by Chikako Yasui (University of Tokyo and the Koyama Astronomical Observatory), a team of scientists has examined this region to better understand how star formation in low-metallicity environments differs from that in the solar neighborhood. The authors’ analysis suggests that sequential star formation is taking place in these low-metallicity regions, triggered by an expanding bubble (the large dashed oval indicated in the image) with a ~30 pc radius. You can find out more about their study by checking out the paper below!
Chikako Yasui et al 2016 AJ 151 115. doi:10.3847/0004-6256/151/5/115
This image shows a computer simulation of the hydrodynamics within a supernova remnant. The mixing between the outer layers (where color represents the log of density) is caused by turbulence from the Rayleigh-Taylor instability, an effect that arises when the expanding core gas of the supernova is accelerated into denser shell gas. The past standard for supernova-evolution simulations was to perform them in one dimension and then, in post-processing, manually smooth out regions that undergo Rayleigh-Taylor turbulence (an intrinsically multidimensional effect). But in a recent study, Paul Duffell (University of California, Berkeley) has explored how a 1D model could be used to reproduce the multidimensional dynamics that occur in turbulence from this instability. For more information, check out the paper below!
Paul C. Duffell 2016 ApJ 821 76. doi:10.3847/0004-637X/821/2/76
This remarkable image (click for the full view!) is a high-resolution map of the 870 µm light emitted by the protoplanetary disk surrounding the young solar analog TW Hydrae. A recent study led by Sean Andrews (Harvard-Smithsonian Center for Astrophysics) presents these observations, obtained with the long-baseline configuration of the Atacama Large Millimeter/submillimeter Array (ALMA) at an unprecedented spatial resolution of ~1 AU. The data represent the distribution of millimeter-sized dust grains in this disk, revealing a beautiful concentric ring structure out to a radial distance of 60 AU from the host star. The apparent gaps in the disk could have any of three origins:
For more information, check out the paper below!
Sean M. Andrews et al 2016 ApJ 820 L40. doi:10.3847/2041-8205/820/2/L40