Starship Asterisk*

Image Credit: ESO/Fred Kamphues

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Images such as this one really highlight the movement of our planet through space. As well as travelling on an elliptical path around the Sun, the Earth spins on its axis — and it is this rotational motion that’s responsible for this eye-catching view.

As the Earth rotates, the stars above appear to change position and move through the sky on long arches, creating these eye-catching star trails centred on the south celestial pole. To successfully capture the apparent motion of the stars, photographer Fred Kamphues took multiple long-exposure shots and stacked them together, creating this remarkable photograph.

The illuminated road below leads up to Paranal Observatory, home to ESO’s Very Large Telescope (VLT). In this image, two of the four main Unit Telescopes (UTs) and the VST can be seen atop the mountain (Cerro Paranal). It is the laser beams from one of these UTs, emphasised by the long exposure photograph, that have created the orange beacon sweeping through the night sky.

Credit: ESA/Hubble & NASA, J. Lee and PHANGS-HST Team

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At around 60 million light-years from Earth, the Great Barred Spiral Galaxy NGC 1365 is captured beautifully in this image by the NASA/ESA Hubble Space Telescope. Located in the constellation of Fornax (The Furnace), the blue and fiery orange swirls show us where stars have just formed and the dusty sites of future stellar nurseries.

At the outer edge of the image, enormous star-forming regions within NGC 1365 can be seen. The bright, light-blue regions indicate the presence of hundreds of baby stars that formed from coalescing gas and dust within the galaxy's outer arms.

This Hubble image was captured as part of a joint survey with the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. The survey will help scientists understand how the diversity of galaxy environments observed in the nearby Universe, including NGC 1365 and previous ESA/Hubble Pictures of the Week such as NGC 2835 and NGC 2775, influence the formation of stars and star clusters. Expected to image over 100 000 gas clouds and star-forming regions beyond our Milky Way, the PHANGS survey is expected to uncover and clarify many of the links between cold gas clouds, star formation and the overall shape and morphology of galaxies.

Image Credit: ESO/Babak Tafreshi (TWAN)

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In this eye-catching Picture of the Week, bright star trails fill the sky above ESO’s La Silla Observatory in Chile. Such trails are formed by the Earth spinning on its axis — our planet’s rotation causes the stars to seemingly move through the sky, slowly tracing out perfect concentric arcs and circles as they do so. A photograph like this therefore requires a long exposure to capture the passage of time.

At the centre of this image is the decommissioned Swedish-ESO Submillimetre Telescope , and the ESO 3.6-metre telescope sits atop the mountain to the left, aglow with activity. This telescope hosts HARPS (the High Accuracy Radial velocity Planet Searcher), which searches for exoplanets by measuring the tiny “wobbling” motions of their host stars as the planets sweep around in their orbits.

Image Credit: ESA/Hubble & NASA, R. Sahai

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This image, taken with the NASA/ESA Hubble Space Telescope, depicts a special class of star-forming nursery known as Free-floating Evaporating Gaseous Globules, or frEGGs for short. This object is formally known as J025157.5+600606.

When a massive new star starts to shine while still within the cool molecular cloud from which it formed, its energetic radiation can ionise the cloud’s hydrogen and create a large, hot bubble of ionised gas. Amazingly, located within this bubble of hot gas around a nearby massive star are the frEGGs: dark compact globules of dust and gas, some of which are giving birth to low-mass stars. The boundary between the cool, dusty frEGG and the hot gas bubble is seen as the glowing purple/blue edges in this fascinating image.

In July 2020 a previous ESA/Hubble Picture of the Week, of J025027.7+600849, featured another frEEG.

Susanna Kohler wrote:

SDO AIA 211 Å ~ Credit: NASA/GSFC/SDO

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How can we tell how much energy is leaking out of active regions on the Sun like the one shown in this Solar Dynamics Observatory (SDO) image above? Active regions are areas with especially strong magnetic fields, and they’re often associated with solar activity. But even when the Sun is generally quiet, these regions radiate energy away — and it’s important to understand how much.

To answer this question, scientists Maria Kazachenko (University of Colorado Boulder; National Solar Observatory) and Hugh Hudson (UC Berkeley; University of Glasgow, UK) used the Extreme Ultraviolet Variability Experiment on board SDO to measure unresolved spectra of the Sun as though it were a distant star. Kazachenko and Hudson compared data from periods when the Sun had no active regions to data from when only one active region was present, allowing them to identify the radiation specifically associated with the active region. ...

• Astrophysical Journal 901(1):64 (2020 Sep 20) DOI: 10.3847/1538-4357/abada6
• arXiv.org > astro-ph > arXiv:2008.02702 > 06 Aug 2020

bystander wrote: ↑Mon Oct 12, 2020 5:50 pm A frEGGS-plosion of Star Formation
ESA Hubble Picture of the Week | 2020 Oct 12

Image Credit: ESA/Hubble & NASA, R. Sahai

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This image, taken with the NASA/ESA Hubble Space Telescope, depicts a special class of star-forming nursery known as Free-floating Evaporating Gaseous Globules, or frEGGs for short. This object is formally known as J025157.5+600606.

When a massive new star starts to shine while still within the cool molecular cloud from which it formed, its energetic radiation can ionise the cloud’s hydrogen and create a large, hot bubble of ionised gas. Amazingly, located within this bubble of hot gas around a nearby massive star are the frEGGs: dark compact globules of dust and gas, some of which are giving birth to low-mass stars. The boundary between the cool, dusty frEGG and the hot gas bubble is seen as the glowing purple/blue edges in this fascinating image.

In July 2020 a previous ESA/Hubble Picture of the Week, of J025027.7+600849, featured another frEEG.