This week’s image comes from NASA’s Juno mission during a flyby back in March. It shows Jupiter’s smallest moon Amalthea orbiting Jupiter with the Great Red Spot in the background. The potato-shaped moon has a radius of 52 miles and completes an orbit of the giant planet in about half an Earth day.
You can read more about the photograph at this NASA site.
This week’s image comes from the NASA/European Space Agency’s Hubble Space Telescope. It shows what is called the Little Dumbbell Nebula, more formally called Messier 76, M76, or NGC 650/651, which is about 3,400 light-years away. The image is being shared as part of the celebration of Hubble’s 34th anniversary, which is discussed in this video.
Here is more on the nebula from NASA:
M76 is classified as a planetary nebula, an expanding shell of glowing gases that were ejected from a dying red giant star. The star eventually collapses to an ultra-dense and hot white dwarf. A planetary nebula is unrelated to planets, but have that name because astronomers in the 1700s using low-power telescopes thought this type of object resembled a planet.
M76 is composed of a ring, seen edge-on as the central bar structure, and two lobes on either opening of the ring. Before the star burned out, it ejected the ring of gas and dust. The ring was probably sculpted by the effects of the star that once had a binary companion star. This sloughed off material created a thick disk of dust and gas along the plane of the companion’s orbit. The hypothetical companion star isn’t seen in the Hubble image, and so it could have been later swallowed by the central star. The disk would be forensic evidence for that stellar cannibalism.
The primary star is collapsing to form a white dwarf. It is one of the hottest stellar remnants known at a scorching 250,000 degrees Fahrenheit, 24 times our Sun’s surface temperature. The sizzling white dwarf can be seen as a pinpoint in the center of the nebula. A star visible in projection beneath it is not part of the nebula.
Pinched off by the disk, two lobes of hot gas are escaping from the top and bottom of the “belt,” along the star’s rotation axis that is perpendicular to the disk. They are being propelled by the hurricane-like outflow of material from the dying star, tearing across space at two million miles per hour. That’s fast enough to travel from Earth to the Moon in a little over seven minutes! This torrential “stellar wind” is plowing into cooler, slower-moving gas that was ejected at an earlier stage in the star’s life, when it was a red giant. Ferocious ultraviolet radiation from the super-hot star is causing the gases to glow. The red color is from nitrogen, and blue is from oxygen.
Given our solar system is 4.6 billion years old, the entire nebula is a flash in the pan by cosmological timekeeping. It will vanish in about 15,000 years.
This week’s image comes from the James Webb Space Telescope (JWST). It shows a close-up of the well known Horsehead Nebula, which is about 1,375 light years from Earth. The clarity of the many galaxies in the distance makes this an even more amazing image.
Here is more about the image from the Webb Space Telescope site:
This image of the Horsehead Nebula from NASA’s James Webb Space Telescope focuses on a portion of the horse’s “mane” that is about 0.8 light-years in width. It was taken with Webb’s NIRCam (Near-infrared Camera). The ethereal clouds that appear blue at the bottom of the image are filled with a variety of materials including hydrogen, methane, and water ice. Red-colored wisps extending above the main nebula represent both atomic and molecular hydrogen. In this area, known as a photodissociation region, ultraviolet light from nearby young, massive stars creates a mostly neutral, warm area of gas and dust between the fully ionized gas above and the nebula below. As with many Webb images, distant galaxies are sprinkled in the background.
This week’s image is a circular nebula that first appears more than 800 years ago, shocking those observing it on Earth at the time and lasting for about 185 days. The circular nebula, called Pa 30, is shown above as a composite of multiple telescopes, including the Chandar X-ray Observatory, which is now facing a threat to its funding.
Hear is more from NASA concerning this image:
X-ray observations by ESA’s XMM-Newton (blue) show the full extent of the nebula and NASA’s Chandra X-ray Observatory (cyan) pinpoints its central source. The nebula is barely visible in optical light but shines bright in infrared light, collected by NASA’s Wide-field Infrared Space Explorer (red and pink). Interestingly, the radial structure in the image consists of heated sulfur that glows in visible light, observed with the ground-based Hiltner 2.4 m telescope at the MDM Observatory (green) in Arizona, USA, as do the stars in the background by Pan-STARRS (white) in Hawaii, USA.
Studies of the composition of the different parts of the remnant have led scientists to believe that it was formed in a thermonuclear explosion, and more precisely a special kind of supernova called a sub-luminous Type Iax event. During this event two white dwarf stars merged, and typically no remnant is expected for this kind of explosion. But incomplete explosions can leave a kind of ‘zombie’ star, such as the massive white dwarf star in this system. This very hot star, one of the hottest stars in the Milky Way (about 200 000 degrees Celsius), has a fast stellar wind with speeds up to 16,000 km/h. The combination of the star and the nebula makes it a unique opportunity for studying such rare explosions.
The image of the week relates to the Total Solar Eclipse that captured the nation’s attention. Goofy glasses like the ones shown in The Chicago Tribune (above) and Wired magazine (below) were worn across the country to watch this rare event.
Our Awesome Universe 