Starship Asterisk*

bystander wrote: ↑Thu Jun 22, 2023 3:27 pm Dark Shrouds in Orion
NOIRLab Image of the Week | KPNO | 2023 Jun 21

Credit: KPNO/NOIRLab/NSF/AURA/T.A. Rector; Processing: T.A. Rector (Univ of Alaska, Anchorage/NOIRLab), M. Zamani (NOIRLab) & D. de Martin (NOIRLab)

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The shadowy clouds of LDN 1622 are pictured in this observation from the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. This image was captured in 2018 by the Mosaic-3 instrument, a wide-field camera used to capture large swaths of the night sky from Kitt Peak in Arizona.

Mosaic-3 has since been retired to make way for the Dark Energy Spectroscopic Instrument (DESI), the most powerful multi-object survey spectrograph in the world. This swap highlights one of the benefits of ground-based astronomy: the ability to upgrade and replace instruments as new technologies become available.

LDN 1622 is a dark nebula, so called because these dense interstellar clouds of gas and dust blot out light from background objects, appearing as ink-dark clouds against a backdrop of stars. This enigmatic cosmic cloud lies 1300 light-years from Earth in the nearby Orion complex, a star-forming region thronging with young stars and other dark nebulae. ...

The Sh2-284 Nebula ~ Image Credit: ESO/VPHAS+ team. Acknowledgement: CASU

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This cloud of orange and red, part of the Sh2-284 nebula, is shown here in spectacular detail using data from the VLT Survey Telescope (VST), hosted by the European Southern Observatory (ESO). This nebula is teeming with young stars, as gas and dust within it clumps together to form new suns. If you take a look at the cloud as a whole, you might be able to make out the face of a cat, smiling down from the sky.

The Sh2-284 stellar nursery is a vast region of dust and gas and its brightest part, visible in this image, is about 150 light-years (over 1400 trillion kilometers) across. It’s located some 15 000 light-years away from Earth in the constellation Monoceros.

Nestled in the centre of the brightest part of the nebula — right under the ‘cat’s nose’ — is a cluster of young stars known as Dolidze 25, which produces large amounts of strong radiation and winds. The radiation is powerful enough to ionise the hydrogen gas in the cloud, thereby producing its bright orange and red colours. It’s in clouds like this that the building blocks for new stars reside.

The winds from the central cluster of stars push away the gas and dust in the nebula, hollowing out its centre. As the winds encounter denser pockets of material, these offer more resistance meaning that the areas around them are eroded away first. This creates several pillars that can be seen along the edges of Sh2-284 pointing at the centre of the nebula, such as the one on the right-hand side of the frame. While these pillars might look small in the image, they are in fact several light-years wide and contain vast amounts of gas and dust out of which new stars form. ...

A galaxy, large and occupying most of the view from the centre. The whole galaxy is made of smooth, diffuse light. In the centre it is brighter and bluer, fading to a pale grey halo that is faint and see-through. The light forms an arm on one side that curls around the top. A couple threads of dark dust cross the centre. Many stars shine around the galaxy, on a black background. (Image Credit: ESA/Hubble & NASA, R. Tully)

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The highly irregular galaxy ESO 174-1, which resembles a lonely, hazy cloud against a backdrop of bright stars, dominates this image from the NASA/ESA Hubble Space Telescope. ESO 174-1 lies around 11 million light-years from Earth and consists of a bright cloud of stars and a faint, meandering tendril of dark gas and dust.

This image is part of a collection of Hubble observations that aims to get to know our nearby galactic neighbours. To be more precise, the observations aim to resolve the brightest stars and basic properties of every known galaxy within 10 megaparsecs. A parsec is a unit used by astronomers to measure the vast distances to other galaxies — 10 megaparsecs translates to 32 million light-years — and makes astronomical distances easier to handle. For example, the nearest star to the Sun, Proxima Centauri, is about 1.3 parsecs away. In everyday units this is a staggering 40 million million kilometres!

The programme to capture all of our neighbouring galaxies was designed to use the 2-3% of Hubble time that absolutely no other observing programme can use. Many of the myriad objects that Hubble observes can only be seen at certain times of year, which makes filling out the observatory’s schedule a daunting logistical challenge. Observing programmes such as the one which captured ESO 174-1 help Hubble’s operators get the most out of every last minute of observing time.

Image Credit: ESO

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Take a look at this aerial photo of the Atacama Pathfinder Experiment, or APEX for short, sat stoically atop the Chajnator plateau in Chile’s Atacama Desert. This remote, dry location, some 5100 metres above sea level, is the perfect location to uncover the secrets of the so-called “cold universe”, the regions in space only a few tens of degrees above absolute zero.

APEX is a 12-metre telescope hosted and operated by ESO on behalf of the Max Planck Institute for Radio Astronomy (MPIfR). It observes at millimetre and submillimetre wavelengths — between infrared and radio waves — where vast cold clouds of interstellar dust and gas glow. These clouds act as the birthplace for new stars and would be obscured in the visible light range.

Light collected by APEX is then recorded by different instruments. One of these, known as the Large APEX Bolometer Camera (LABOCA), has an array of 295 “pixels” known as bolometers (highly sensitive thermometers) which are used to detect tiny fluctuations in the faint radiation coming from astronomical objects. To do this, each bolometer must be cooled to less than 0.3 degrees above absolute zero — that’s a very chilly -272.85 degrees Celsius! With this advanced equipment, APEX peers into remote clouds of cold gas from the chilly solitude of the Atacama Desert.

Credit: KPNO/NOIRLab/NSF/AURA/T.A. Rector; Processing: T.A. Rector (Univ of Alaska, Anchorage/NOIRLab), M. Zamani (NOIRLab) & D. de Martin (NOIRLab)

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The shadowy clouds of LDN 1622 are pictured in this observation from the Nicholas U. Mayall 4-meter Telescope at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab. This image was captured in 2018 by the Mosaic-3 instrument, a wide-field camera used to capture large swaths of the night sky from Kitt Peak in Arizona.

Mosaic-3 has since been retired to make way for the Dark Energy Spectroscopic Instrument (DESI), the most powerful multi-object survey spectrograph in the world. This swap highlights one of the benefits of ground-based astronomy: the ability to upgrade and replace instruments as new technologies become available.

LDN 1622 is a dark nebula, so called because these dense interstellar clouds of gas and dust blot out light from background objects, appearing as ink-dark clouds against a backdrop of stars. This enigmatic cosmic cloud lies 1300 light-years from Earth in the nearby Orion complex, a star-forming region thronging with young stars and other dark nebulae. ...

A cluster of stars in warm and cool colours. The whole view is filled with small stars,
which become much denser and brighter around a core just right of centre. Most of
the stars are small, but some are larger with a round, brightly-coloured glow and
four sharp diffraction spikes. Behind the stars, a dark background can be seen.
(Image Credit: ESA/Hubble & NASA, W. Lewin, F. R. Ferraro)

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The teeming stars of the globular cluster NGC 6544 glisten in this image from the NASA/ESA Hubble Space Telescope. This cluster of tightly bound stars lies more than 8000 light-years away from Earth and is — like all globular clusters — a densely populated region of tens of thousands of stars.

This image of NGC 6544 combines data from two of Hubble’s instruments — the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) — as well as two separate astronomical observations. The first observation was designed to find a visible counterpart to the radio pulsar discovered in NGC 6544. A pulsar is the rapidly spinning remnant of a dead star, emitting twin beams of electromagnetic radiation like a vast astronomical lighthouse. This pulsar rotates particularly quickly, and astronomers turned to Hubble to help determine how this object evolved in NGC 6544.

The second observation which contributed data to this image was also designed to find the visible counterparts of objects detected at other electromagnetic wavelengths. Instead of matching up sources to a pulsar, however, astronomers used Hubble to search for the counterparts of faint X-ray sources. Their observations could help explain how clusters like NGC 6544 change over time.

NGC 6544 lies in the constellation Sagittarius, close to the vast Lagoon Nebula, a hazy labyrinth of gas and dust sculpted by the fierce winds of newly born stars. The Lagoon Nebula is truly colossal — even by astronomical standards — and measures 55 light-years across and 20 light-years from top to bottom. Previous Hubble images of the nebula incorporated infrared observations to reveal young stars and intricate structures that would be obscured at visible wavelengths by clouds of gas and dust.

bystander wrote: ↑Thu Jun 15, 2023 1:53 pm A Dishevelled Irregular Galaxy
ESA Hubble Picture of the Week | 2023 Jun 12

A galaxy fills up most of the frame from the right. It is fuzzy and diffuse, but made up of numerous tiny stars. In the core, the stars merge into a glowing bar shape. The gas and stars in the galaxy vary between warm and cool colours. They are spread over a large area, the colours mixing like clouds. The glow of the galaxy fades into a black background, with a few stars and small, distant galaxies. (Credit: ESA/Hubble & NASA, C. Kilpatrick)

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The galaxy NGC 7292 billows across this image from the NASA/ESA Hubble Space Telescope, accompanied by a handful of bright stars and the indistinct smudges of extremely distant galaxies in the background. It lies around 44 million light-years from Earth in the constellation Pegasus.

This slightly dishevelled galaxy is irregular, meaning that it lacks the distinct spiral arms of galaxies like the Whirlpool Galaxy or the smooth elliptical shape of galaxies like Messier 59. Unusually, its core is stretched out into a distinct bar, a feature seen in many spiral galaxies. Alongside its hazy shape, NGC 7292 is remarkably faint. As a result, astronomers classify NGC 7292 as a low surface brightness galaxy, barely distinguishable against the backdrop of the night sky. Such galaxies are typically dominated by gas and dark matter rather than stars.

Astronomers directed Hubble to inspect NGC 7292 during an observational campaign studying the aftermath of Type II supernovae. These colossal explosions happen when a massive star collapses and then violently rebounds in a catastrophic explosion that tears the star apart. Astronomers hope to learn more about the diversity of Type II supernovae they have observed by scrutinising the aftermath and remaining nearby stars of a large sample of historical Type II supernovae.

NGC 7292’s supernova was observed in 1964 and accordingly given the identifier SN 1964H. Studying the stellar neighbourhood of SN 1964H helps astronomers estimate the initial mass of the star that went supernova, and could uncover surviving stellar companions that once shared a system with the star that would become SN 1964H.

Credit: CTIO/NOIRLab/NSF/AURA/T. Slovinský

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Below the southern skies, the telescopes of Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, bask in the starlight of the brilliant Milky Way. Speckled with multi-colored stars, our home galaxy in this image stretches down into the city-lit horizon, just grazing past the Víctor M. Blanco 4-meter Telescope (left) and SMARTS 1.5-meter Telescope (right). The Small and Large Magellanic Clouds that accompany our home galaxy are seen to the left of the Blanco telescope. In between the telescopes blooms a deep shade of red that permeates through the tendrils of the Milky Way. This is the Gum Nebula, an emission nebula that blazes with the light of gas ionized by its host stars. From our perspective it holds a bountiful number of cosmic objects, from globular clusters, to the Vela Pulsar, and even to an 11,000-year-old supernova remnant.

A galaxy fills up most of the frame from the right. It is fuzzy and diffuse, but made up of numerous tiny stars. In the core, the stars merge into a glowing bar shape. The gas and stars in the galaxy vary between warm and cool colours. They are spread over a large area, the colours mixing like clouds. The glow of the galaxy fades into a black background, with a few stars and small, distant galaxies. (Credit: ESA/Hubble & NASA, C. Kilpatrick)

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The galaxy NGC 7292 billows across this image from the NASA/ESA Hubble Space Telescope, accompanied by a handful of bright stars and the indistinct smudges of extremely distant galaxies in the background. It lies around 44 million light-years from Earth in the constellation Pegasus.

This slightly dishevelled galaxy is irregular, meaning that it lacks the distinct spiral arms of galaxies like the Whirlpool Galaxy or the smooth elliptical shape of galaxies like Messier 59. Unusually, its core is stretched out into a distinct bar, a feature seen in many spiral galaxies. Alongside its hazy shape, NGC 7292 is remarkably faint. As a result, astronomers classify NGC 7292 as a low surface brightness galaxy, barely distinguishable against the backdrop of the night sky. Such galaxies are typically dominated by gas and dark matter rather than stars.

Astronomers directed Hubble to inspect NGC 7292 during an observational campaign studying the aftermath of Type II supernovae. These colossal explosions happen when a massive star collapses and then violently rebounds in a catastrophic explosion that tears the star apart. Astronomers hope to learn more about the diversity of Type II supernovae they have observed by scrutinising the aftermath and remaining nearby stars of a large sample of historical Type II supernovae.

NGC 7292’s supernova was observed in 1964 and accordingly given the identifier SN 1964H. Studying the stellar neighbourhood of SN 1964H helps astronomers estimate the initial mass of the star that went supernova, and could uncover surviving stellar companions that once shared a system with the star that would become SN 1964H.

Credit: ESO

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It might look like there’s not a lot going on in this Picture of the Week, but looks can be deceiving. Far off in the distance, huddled together like penguins in an Antarctic storm, sit the 66 high-precision antennas of the Atacama Large Millimeter/submillimeter Array (ALMA). Operated by ESO together with international partners, ALMA is designed to study the light emitted by the coldest objects in the Universe, such as vast cold clouds in interstellar space.

Stretching out either side of the antennas is the empty landscape of the Chajnantor plateau. Sitting at 5,000 m above sea level in the Chilean Andes, this remote location is one of the driest places on Earth. It’s this dryness that makes it the perfect place for observing the signals from the cold Universe which would otherwise be heavily absorbed by water vapour in our atmosphere.

ALMA is what’s known as an interferometer, meaning that its individual antennas work together, acting to form a more powerful telescope that can discern details smaller than what can be seen with the individual antennas. Depending on what observations are being carried out, the antennas are arranged in different configurations. The further away they are, the finer the details they can see; more compact configurations, on the other side, offer better sensitivity and are ideal when observing diffuse extended objects. Here the antennas are in one of the most compact configurations, but the distance between them can be as great as 16 kilometres!

Image Credit: KPNO/NOIRLab/NSF/AURA/T. Slovinský

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The eighteen-story Nicholas U. Mayall 4-meter Telescope is located at Kitt Peak National Observatory (KPNO), a Program of NSF’s NOIRLab, and is seen here against the backdrop of two celestial landmarks of the northern hemisphere: The constellation Ursa Major (the Great Bear), with its seven bright stars that make the Big Dipper, on the right side of Mayall and the North Star Polaris on the left.

The stars of the Big Dipper asterism are notable even on their own. The second star in the Big Dipper’s handle is Mizar and together with its fainter companion star Alcor they are known as the Horse and Rider. Their pairing is a naked-eye double since they appear to observers to be right next to each other. Because of their close proximity, trying to resolve the pair with only the naked eye has been a traditional sight test in many countries. The stars Merak (blue) and Dubhe (white), that form the front of the Big Dipper’s cup, are often used for celestial navigation. By connecting the two with an imaginary line and extending it across the sky, the North Star Polaris can easily be located, seen here the brightest star to the far left of the Mayall telescope. Polaris’s stable position has made it useful for northern hemisphere navigation since the 5th century. ...

A close-in image of a spiral galaxy, showing its core and part of a spiral arm. Thousands upon thousands of tiny stars that make it up can be seen, most dense in a whitish bar that forms its core. Clumps and filaments of dust form an almost skeletal structure that follows the twist of the galaxy and its spiral arm. Large, glowing bubbles of red gas are hidden in the dust. ~ Credit: ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST Team

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A delicate tracery of dust and bright star clusters threads across this image from the NASA/ESA/CSA James Webb Space Telescope. The bright tendrils of gas and stars belong to the barred spiral galaxy NGC 5068, whose bright central bar is visible in the upper left of this image. NGC 5068 lies around 17 million light-years from Earth in the constellation Virgo.

This portrait of NGC 5068 is part of a campaign to create an astronomical treasure trove, a repository of observations of star formation in nearby galaxies. Previous gems from this collection can be seen here and here. These observations are particularly valuable to astronomers for two reasons. The first is because star formation underpins so many fields in astronomy, from the physics of the tenuous plasma that lies between stars to the evolution of entire galaxies. By observing the formation of stars in nearby galaxies, astronomers hope to kick-start major scientific advances with some of the first available data from Webb. ...

This image is a composite of image data from two of Webb's instruments, MIRI and NIRCam.