Starship Asterisk*

Credit: ESO / VLT / FORS

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This beautiful image, captured with the FOcal Reducer and low dispersion Spectrograph (FORS) on ESO’s Very Large Telescope (VLT), shows a field of stars of all ages — some looming close in the foreground, and others lurking in the far distance. The distinct red and blue hues are thanks to the use of filters, which allow the selection of specific wavelength ranges of light. The images collected with different filters can be combined in order to create colourful composite images: by assigning a particular color to each filter; colouring the images according to the filter used; then combining the separate images. The result is a spectacular image which colourfully represents the various wavelengths of light.

This patch of sky is found in the constellation of Crux (The Southern Cross), an extremely bright section of the Milky Way. It was imaged as part of the ESO Cosmic Gems programme, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

Image Credit: ESA/Hubble & NASA, M. Stiavelli

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Captured by the NASA/ESA Hubble Space Telescope, this image shows NGC 7513, a barred spiral galaxy. Located approximately 60 million light-years away, NGC 7513 lies within the Sculptor constellation in the southern hemisphere.

This galaxy is moving at the astounding speed of 1564 kilometres per second, and it is heading away from us. For context, the Earth orbits the Sun at about 30 kilometres per second. Though NGC 7513’s apparent movement away from the Milky Way might seem strange, it is not that unusual.

While some galaxies, like the Milky Way and the Andromeda galaxy, are caught in each other’s gravitational pull and will eventually merge together, the vast majority of galaxies in our Universe appear to be moving away from each other. This phenomenon is due to the expansion of the Universe, and it is the space between galaxies that is stretching, rather than the galaxies themselves moving.

bystander wrote: ↑Mon Jul 06, 2020 2:24 pm The Sculpted Galaxy
ESA Hubble Picture of the Week | 2020 July 06

Image Credit: ESA/Hubble & NASA, M. Stiavelli

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Captured by the NASA/ESA Hubble Space Telescope, this image shows NGC 7513, a barred spiral galaxy. Located approximately 60 million light-years away, NGC 7513 lies within the Sculptor constellation in the southern hemisphere.

This galaxy is moving at the astounding speed of 1564 kilometres per second, and it is heading away from us. For context, the Earth orbits the Sun at about 30 kilometres per second. Though NGC 7513’s apparent movement away from the Milky Way might seem strange, it is not that unusual.

While some galaxies, like the Milky Way and the Andromeda galaxy, are caught in each other’s gravitational pull and will eventually merge together, the vast majority of galaxies in our Universe appear to be moving away from each other. This phenomenon is due to the expansion of the Universe, and it is the space between galaxies that is stretching, rather than the galaxies themselves moving.

starsurfer wrote: ↑Thu Jul 09, 2020 3:12 pm NGC 1501
https://www.hansonastronomy.com/ngc1501
Copyright: Mark Hanson
NGC1501.jpg

An unprocessed image from the WISPR instrument on board NASA’s Parker Solar Probe shows comet NEOWISE on July 5, 2020, shortly after its closest approach to the Sun. The Sun is out of frame to the left. The faint grid pattern near the center of the image is an artifact of the way the image is created. The small black structure near the lower left of the image is caused by a grain of dust resting on the imager’s lens. Credits: NASA/JHU APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher

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Processed data from the WISPR instrument on NASA’s Parker Solar Probe shows
greater detail in the twin tails of comet NEOWISE, as seen on July 5, 2020. The lower,
broader tail is the comet’s dust tail, while the thinner, upper tail is the comet’s ion tail.
Credits: NASA/JHU APL/Naval Research Lab/Parker Solar Probe/Guillermo Stenborg

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NASA’s Parker Solar Probe was at the right place at the right time to capture a unique view of comet NEOWISE on July 5, 2020. Parker Solar Probe’s position in space gave the spacecraft an unmatched view of the comet’s twin tails when it was particularly active just after its closest approach to the Sun, called perihelion.

The comet was discovered by NASA’s Near-Earth Object Wide-field Infrared Survey Explorer, or [urlhttps://www.nasa.gov/neowise]NEOWISE[/url], on March 27. Since then, the comet — called comet C/2020 F3 NEOWISE and nicknamed comet NEOWISE — has been spotted by several NASA spacecraft, including Parker Solar Probe, NASA’s Solar and Terrestrial Relations Observatory (STEREO), the ESA/NASA Solar and Heliospheric Observatory (SOHO), and astronauts aboard the International Space Station.

The image above is unprocessed data from Parker Solar Probe’s WISPR instrument, which takes images of the Sun’s outer atmosphere and solar wind in visible light. WISPR’s sensitivity also makes it well-suited to see fine detail in structures like comet tails. Parker Solar Probe collected science data through June 28 for its fifth solar flyby, but the availability of additional downlink time allowed the team to take extra images, including this image of comet NEOWISE.

The twin tails of comet NEOWISE are seen more clearly in this image from the WISPR instrument, which has been processed to increase contrast and remove excess brightness from scattered sunlight, revealing more detail in the comet tails.

The lower tail, which appears broad and fuzzy, is the dust tail of comet NEOWISE — created when dust lifts off the surface of the comet’s nucleus and trails behind the comet in its orbit. Scientists hope to use WISPR’s images to study the size of dust grains within the dust tail, as well as the rate at which the comet sheds dust.

The upper tail is the ion tail, which is made up of gases that have been ionized by losing electrons in the Sun’s intense light. These ionized gases are buffeted by the solar wind — the Sun’s constant outflow of magnetized material — creating the ion tail that extends directly away from the Sun. Parker Solar Probe’s images appear to show a divide in the ion tail. This could mean that comet NEOWISE has two ion tails, in addition to its dust tail, though scientists would need more data and analysis to confirm this possibility.

Susanna Kohler wrote:

Could TOI-700 d, an Earth-sized planet in the habitable zone of an early-type M-dwarf star, have held on to its atmosphere over long timescales? This question is crucial to understanding whether this recent discovery from the Transiting Exoplanet Survey Satellite (TESS) is likely to have a habitable surface. In a recent study led by Chuanfei Dong (Princeton University), a team of scientists conducted a series of state-of-the-art simulations to model the atmospheric escape from TOI-700 d as the planet is bombarded by its host’s stellar wind. The plots show the O+ ion density and magnetic field lines in various cases from the authors’ simulations (see the original image for scales and additional detail). Though TOI-700 d’s atmospheric ion escape rates could be a few orders of magnitude higher than the rates typical of the terrestrial planets in our own solar system, the authors show that TOI-700 d could still retain a substantial atmosphere for more than a billion years — so it may well be worth exploring this planet further in the future! For more information, check out the full article below.

• Astrophysical Journal Letters 896(2):L24 (2020 Jun 20) DOI: 10.3847/2041-8213/ab982f
• arXiv.org > astro-ph > arXiv:2005.13190 > 27 May 2020 (v1), 09 Jun 2020 (v2)