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Down the rabbit hole

Cassiopeia A (Cas A) is a supernova remnant located about 11 000 light-years from Earth in the constellation Cassiopeia. It spans approximately 10 light-years. This image, released in April 2023, uses data from Webb’s Mid-Infrared Instrument (MIRI) to reveal Cas A in a new light.

On the remnant’s exterior, particularly at the top and left, lie curtains of material, appearing orange and red, that are due to emission from warm dust. This marks where ejected material from the exploded star is ramming into surrounding circumstellar material.

Interior to this outer shell lie mottled filaments of bright pink studded with clumps and knots. This is material from the star itself, and likely shines due to a mix of various heavy elements and dust emission. The stellar material can also be seen as fainter wisps near the cavity’s interior.

A loop represented in green extends across the right side of the central cavity. Its shape and complexity are unexpected and challenging for scientists to understand.

[Image description: A roughly square image is rotated clockwise about 45 degrees. Within the image is a roughly circular nebula with a complex structure. On the circle’s exterior lie curtains of material glowing orange. Interior to this outer shell lies a ring of mottled filaments of bright pink studded with clumps and knots. At centre right, a greenish loop extends from the right side of the ring into the central cavity. Translucent wisps of blue, green, and red appear throughout the image.]

CREDIT

NASA, ESA, CSA, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (UGent), J. DePasquale (STScI)

This image from the NASA/ESA/CSA James Webb Space Telescope features an H II region in the Large Magellanic Cloud (LMC), a satellite galaxy of our Milky Way. This nebula, known as N79, is a region of interstellar atomic hydrogen that is ionised, captured here by Webb’s Mid-InfraRed Instrument (MIRI).

N79 is a massive star-forming complex spanning roughly 1630 light-years in the generally unexplored southwest region of the LMC. N79 is typically regarded as a younger version of 30 Doradus (also known as the Tarantula Nebula), another of Webb’s recent targets. Research suggests that N79 has a star formation efficiency exceeding that of 30 Doradus by a factor of two over the past 500 000 years.

This particular image centres on one of the three giant molecular cloud complexes, dubbed N79 South (S1 for short). The distinct ‘starburst’ pattern surrounding this bright object is a series of diffraction spikes. All telescopes which use a mirror to collect light, as Webb does, have this form of artifact which arises from the design of the telescope. In Webb's case, the six largest starburst spikes appear because of the hexagonal symmetry of Webb's 18 primary mirror segments. Patterns like these are only noticeable around very bright, compact objects, where all the light comes from the same place. Most galaxies, even though they appear very small to our eyes, are darker and more spread out than a single star, and therefore do not show this pattern.

At the longer wavelengths of light captured by MIRI, Webb’s view of N79 showcases the region’s glowing gas and dust. This is because mid-infrared light is able to reveal what is happening deeper inside the clouds (while shorter wavelengths of light would be absorbed or scattered by dust grains in the nebula). Some still-embedded protostars also appear in this field.

Star-forming regions such as this are of interest to astronomers because their chemical composition is similar to that of the gigantic star-forming regions observed when the Universe was only a few billion years old and star formation was at its peak. Star-forming regions in our Milky Way galaxy are not producing stars at the same furious rate as N79, and have a different chemical composition. Webb is now providing astronomers the opportunity to compare and contrast observations of star formation in N79 with the telescope’s deep observations of distant galaxies in the early Universe.

These observations of N79 are part of a Webb programme that is studying the evolution of the circumstellar discs and envelopes of forming stars over a wide range in mass and at different evolutionary stages. Webb’s sensitivity will enable scientists to detect for the first time the planet-forming dust discs around stars of similar mass to that of our Sun at the distance of the LMC.

This image includes 7.7-micron light shown in blue, 10 microns in cyan, 15 microns in yellow, and 21 microns in red (770W, 1000W, 1500W, and 2100W filters, respectively).

[Image description: A bright young star within a colourful nebula. The star is identifiable as the brightest spot in the image, surrounded by six large spokes of light that cross the image. A number of other bright spots can also be seen in the clouds, which are shown in great detail as layers of colourful wisps.]

CREDIT

ESA/Webb, NASA & CSA, M. Meixner

http://www.esa.int/ESA_Multimedia/Images/2024/01/A_massive_cluster_is_born

A beautiful but skewed spiral galaxy dazzles in today’s NASA/ESA Hubble Space Telescope Picture of the Week. This galaxy, called Arp 184 or NGC 1961, sits about 190 million light-years away from Earth in the constellation Camelopardalis (The Giraffe).

The name Arp 184 comes from the Atlas of Peculiar Galaxies, which was compiled by astronomer Halton Arp in 1966. The 338 galaxies in the atlas are oddly shaped, tending to be neither entirely elliptical nor entirely spiral-shaped. Many of the galaxies are in the process of interacting with other galaxies, while others are dwarf galaxies without well-defined structures. Arp 184 earned its spot in the catalogue thanks to its single broad, star-speckled spiral arm that appears to stretch toward us. The galaxy’s far side sports a few wisps of gas and stars but lacks a similarly impressive spiral arm.

This Hubble image combines data from three Snapshot observing programmes, which are composed of short observations that can be slotted into time gaps between other proposals. One of the three programmes targeted Arp 184 for its peculiar appearance. This programme surveyed galaxies listed in the Atlas of Peculiar Galaxies as well as A Catalogue of Southern Peculiar Galaxies and Associations, a similar catalogue compiled by Halton Arp and Barry Madore.

The remaining two programmes were designed to check up on the aftermath of fleeting astronomical events like supernovae and tidal disruption events — when a star is ripped apart after wandering too close to a supermassive black hole. Since Arp 184 has hosted four known supernovae in the past three decades, it’s a rich target for a supernova hunt.

[Image Description: A spiral galaxy seen at a skewed angle. Its centre is a bright spot radiating light. A thick, stormy disc of material surrounds this, with swirling strands of dark dust and bright spots of star formation strewn through the disc. A large spiral arm extends from the disc towards the viewer. Some foreg

CREDIT

ESA/Hubble & NASA, J. Dalcanton, R. J. Foley

(UC Santa Cruz), C. Kilpatrick

http://www.esa.int/About_Us/Week_in_images/Week_in_images_28_April_-_02_May_2025

Comment: I do not know why the last sentence in their description ends with an incomplete sentence.

Telescopes, including Hubble, have monitored the Eta Carinae star system for more than two decades. It has been prone to violent outbursts, including an episode in the 1840s during which ejected material formed the bipolar bubbles seen here.

Now, using Hubble’s Wide Field Camera 3 to probe the nebula in ultraviolet light, astronomers have uncovered the glow of magnesium embedded in warm gas (shown in blue) in places they had not seen it before. The luminous magnesium resides in the space between the dusty bipolar bubbles and the outer shock-heated nitrogen-rich filaments (shown in red). The streaks visible in the blue region outside the lower-left lobe are a striking feature of the image. These streaks are created when the star’s light rays poke through the dust clumps scattered along the bubble’s surface. Wherever the ultraviolet light strikes the dense dust, it leaves a long, thin shadow that extends beyond the lobe into the surrounding gas.

Eta Carinae resides 7500 light-years away.

CREDIT

NASA, ESA, N. Smith (University of Arizona, >Tucson), and J. Morse (BoldlyGo Institute, New York); CC BY 4.0

http://www.esa.int/ESA_Multimedia/Search?SearchText=carina&amp%3Bresult_type=images

Source: http://khc.qcc.cuny.edu/camps/charts/

cross-posted from: http://beehaw.org/post/19763859

At the capitol building before the march

cross-posted from: http://beehaw.org/post/19763859

At the capitol building before the march