** What’s Up: November 2022 Skywatching Tips from NASA – NASA JPL
What are some skywatching highlights in November 2022?
A total lunar eclipse brings some magic to the morning sky on November 8th, and the Leonid meteors peak after midnight on November 18th, with some glare from a 35% full moon. In addition, enjoy pretty views on other days in November when the Moon visits planets Mars and Saturn, and bright star Spica.
0:00 Intro 0:10 Total lunar eclipse 1:25 Moon & planet highlights 2:16 Leonid meteor shower 3:15 Nov ember Moon phases
Additional information about topics covered in this episode of What’s Up, along with still images from the video, and the video transcript, are available at https://solarsystem.nasa.gov/skywatch….
In November, hunt for the fainter constellations of fall, including Pisces, Aries, and Triangulum. They will guide you to find several galaxies and a pair of white stars. Stay tuned for space-based views of spiral galaxy M74 and the Triangulum Galaxy, which are shown in visible, infrared, and ultraviolet light
Pete Lawrence and Paul Abel reveal the best things to see in the night sky this month, including observing Mars as it approaches opposition, catching Jupiter’s Galilean moons, the Leonid meteor shower, the Orion constellation, the Winter Triangle asterism and the Crab Nebula.
Our monthly Sky Tour #astronomy #podcast provides an informative and entertaining 10-minute guided tour of the nighttime sky. Listen to the November episode and learn about the total #lunareclipse, check out three bright #planets in the evening sky, get the lowdown on a celestial queen, and get ready for three #meteor showers.
This image shows a spectacular view of the orange and pink clouds that make up what remains after the explosive death of a massive star — the Vela supernova remnant. This detailed image consists of 554 million pixels, and is a combined mosaic image of observations taken with the 268-million-pixel OmegaCAM camera at the VLT Survey Telescope, hosted at ESO’s Paranal Observatory. OmegaCAM can take images through several filters that each let the telescope see the light emitted in a distinct colour. To capture this image, four filters have been used, represented here by a combination of magenta, blue, green and red. The result is an extremely detailed and stunning view of both the gaseous filaments in the remnant and the foreground bright blue stars that add sparkle to the image.
A spooky spider web, magical dragons or wispy trails of ghosts? What do you see in this image of the Vela supernova remnant? This beautiful tapestry of colours shows the ghostly remains of a gigantic star, and was captured here in incredible detail with the VLT Survey Telescope, hosted at the European Southern Observatory’s (ESO’s) Paranal site in Chile.
The wispy structure of pink and orange clouds is all that remains of a massive star that ended its life in a powerful explosion around 11 000 years ago. When the most massive stars reach the end of their life, they often go out with a bang, in an outburst called a supernova. These explosions cause shock waves that move through the surrounding gas, compressing it and creating intricate thread-like structures. The energy released heats the gaseous tendrils, making them shine brightly, as seen in this image.
In this 554-million-pixel image, we get an extremely detailed view of the Vela supernova remnant, named after the southern constellation Vela (The Sails). You could fit nine full Moons in this entire image, and the whole cloud is even larger. At only 800 light-years away from Earth, this dramatic supernova remnant is one of the closest known to us.
As it exploded, the outermost layers of the progenitor star were ejected into the surrounding gas, producing the spectacular filaments that we observe here. What remains of the star is an ultra-dense ball in which the protons and electrons are forced together into neutrons — a neutron star. The neutron star in the Vela remnant, placed slightly outside of this image to the upper left, happens to be a pulsar that spins on its own axis at an incredible speed of more than 10 times per second.
Dive into the details of the Vela supernova remnant with these 12 highlights, each showing a different intricate part of the beautiful pink and orange gaseous clouds and the bright stars in the foreground and background.
This image is a mosaic of observations taken with the wide-field camera OmegaCAM at the VLT Survey Telescope (VST), hosted at ESO’s Paranal Observatory in Chile. The 268-million-pixel camera can take images through several filters that let through light of different colours. In this particular image of the Vela remnant, four different filters were used, represented here by a combination of magenta, blue, green and red.
The VST is owned by The National Institute for Astrophysics in Italy, INAF, and with its 2.6-metre mirror it is one of the largest telescopes dedicated to surveying the night sky in visible light. This image is an example from such a survey: the VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+). For over seven years, this survey has mapped a considerable portion of our home galaxy, allowing astronomers to better understand how stars form, evolve and eventually die.
This image shows the process of going from the raw data captured by a telescope to a stunning astronomical image like the one featured here, showing the Vela supernova remnant as seen with the VLT Survey Telescope (VST). The detector registers the light collected by the telescope. OmegaCAM, the camera attached to the VST, has an array of 32 detectors covering a large field of view. The raw images contain artefacts and instrumental signatures such as dead pixels, shadows, or luminosity variations among detectors. These need to be corrected before the images can be used for scientific purposes. Astronomers correct these effects using calibration data. This process of going from raw to science-ready data is called ‘data reduction’. When an astronomical object is larger than the field of view one needs to stitch together different images, typically called a mosaic. This also allows us to fill in the gaps in between the detectors. The brightness of the background can vary among different parts of the mosaic, especially if they were observed on different nights, because of changes in the phase of the Moon and other effects. For instance, the upper-left corner of image 4 is darker than the rest of the image. By comparing overlapping areas between different images this can be corrected for. The mosaiced image is visually inspected, and any residual artefacts are corrected for. This includes, for example, imperfect seams between adjacent images. Astronomical detectors don’t capture colour images. Instead, several images are taken separately through filters that let through light of different wavelengths. These images are then assigned different colours and combined into a final colour image. The final colour image.
This artist’s impression shows an ultra-hot exoplanet, a planet beyond our Solar System, as it is about to transit in front of its host star. When the light from the star passes through the planet’s atmosphere, it is filtered by the chemical elements and molecules in the gaseous layer. With sensitive instruments, the signatures of those elements and molecules can be observed from Earth. Using the ESPRESSO instrument of ESO’s Very Large Telescope, astronomers have found the heaviest element yet in an exoplanet’s atmosphere, barium, in the two ultra-hot Jupiters WASP-76 b and WASP-121 b.
Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered the heaviest element ever found in an exoplanet atmosphere — barium. They were surprised to discover barium at high altitudes in the atmospheres of the ultra-hot gas giants WASP-76 b and WASP-121 b — two exoplanets, planets which orbit stars outside our Solar System. This unexpected discovery raises questions about what these exotic atmospheres may be like.
“The puzzling and counterintuitive part is: why is there such a heavy element in the upper layers of the atmosphere of these planets?”
says Tomás Azevedo Silva, a PhD student at the University of Porto and the Instituto de Astrofísica e Ciências do Espaço (IA) in Portugal who led the study published today in Astronomy & Astrophysics.
WASP-76 b and WASP-121 b are no ordinary exoplanets. Both are known as ultra-hot Jupiters as they are comparable in size to Jupiter whilst having extremely high surface temperatures soaring above 1000°C. This is due to their close proximity to their host stars, which also means an orbit around each star takes only one to two days. This gives these planets rather exotic features; in WASP-76 b, for example, astronomers suspect it rains iron.
But even so, the scientists were surprised to find barium, which is 2.5 times heavier than iron, in the upper atmospheres of WASP-76 b and WASP-121 b.
“Given the high gravity of the planets, we would expect heavy elements like barium to quickly fall into the lower layers of the atmosphere,”
explains co-author Olivier Demangeon, a researcher also from the University of Porto and IA.
“This was in a way an ‘accidental’ discovery,” says Azevedo Silva. “We were not expecting or looking for barium in particular and had to cross-check that this was actually coming from the planet since it had never been seen in any exoplanet before.”
The fact that barium was detected in the atmospheres of both of these ultra-hot Jupiters suggests that this category of planets might be even stranger than previously thought. Although we do occasionally see barium in our own skies, as the brilliant green colour in fireworks, the question for scientists is what natural process could cause this heavy element to be at such high altitudes in these exoplanets.
“At the moment, we are not sure what the mechanisms are,”
explains Demangeon.
This illustration shows a night-side view of the exoplanet WASP-76 b. The ultra-hot giant exoplanet has a day side where temperatures climb above 2400 degrees Celsius, high enough to vaporise metals. Strong winds carry iron vapour to the cooler night side where it condenses into iron droplets. To the left of the image, we see the evening border of the exoplanet, where it transitions from day to night.
In the study of exoplanet atmospheres ultra-hot Jupiters are extremely useful. As Demangeon explains:
“Being gaseous and hot, their atmospheres are very extended and are thus easier to observe and study than those of smaller or cooler planets”.
Determining the composition of an exoplanet’s atmosphere requires very specialised equipment. The team used the ESPRESSO instrument on ESO’s VLT in Chile to analyse starlight that had been filtered through the atmospheres of WASP-76 b and WASP-121 b. This made it possible to clearly detect several elements in them, including barium.
These new results show that we have only scratched the surface of the mysteries of exoplanets. With future instruments such as the high-resolution ArmazoNes high Dispersion Echelle Spectrograph (ANDES), which will operate on ESO’s upcoming Extremely Large Telescope (ELT), astronomers will be able to study the atmospheres of exoplanets large and small, including those of rocky planets similar to Earth, in much greater depth and to gather more clues as to the nature of these strange worlds.
** What’s Up: October 2022 Skywatching Tips from NASA – NASA JPL
What are some skywatching highlights in October 2022? Enjoy giant planets Jupiter and Saturn all night throughout the month. Then watch as Mars begins its retrograde motion, moving westward each night instead of eastward, for the next few months. Finally, check out the Orionid meteors overnight on Oct. 20.
0:00 Intro 0:11 Evenings with Jupiter & Saturn 0:37 Mars’ retrograde motion 2:07 Orionid meteor shower 3:04 October Moon phases
Additional information about topics covered in this episode of What’s Up, along with still images from the video, and the video transcript, are available at https://solarsystem.nasa.gov/skywatch…
Crisp, clear October nights are full of celestial showpieces. Find Pegasus, the flying horse of Greek myth, to pinpoint dense globular star clusters and galaxies, and keep watching for space-based views of M15, NGC 7331, and the Andromeda Galaxy.
What’s in the night sky tonight? Get ready for Mars opposition, make the most of Uranus (and prepare for a lunar occultation at the end of the year), observe Neptune following its September opposition, see Jupiter’s Galilean moons, take in the Orionid meteor shower and admire the Summer Triangle asterism.
Our monthly Sky Tour #astronomy #podcast provides an informative and entertaining 10-minute guided tour of the nighttime sky. Listen to the October episode and give #Jupiter a really close look, learn what #Andromeda and #Pegasus have in common, circle around the pole #star #Polaris, and watch for #meteors shed by #Halley’s #Comet
This shows a still image of the supermassive black hole Sagittarius A*, as seen by the Event Horizon Collaboration (EHT), with an artist’s illustration indicating where the modelling of the ALMA data predicts the hot spot to be and its orbit around the black hole. Credits: ESO
Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have spotted signs of a ‘hot spot’ orbiting Sagittarius A*, the black hole at the centre of our galaxy. The finding helps us better understand the enigmatic and dynamic environment of our supermassive black hole.
“We think we’re looking at a hot bubble of gas zipping around Sagittarius A* on an orbit similar in size to that of the planet Mercury, but making a full loop in just around 70 minutes. This requires a mind blowing velocity of about 30% of the speed of light!”
says Maciek Wielgus of the Max Planck Institute for Radio Astronomy in Bonn, Germany, who led the study published today in Astronomy & Astrophysics.
The observations were made with ALMA in the Chilean Andes — a radio telescope co-owned by the European Southern Observatory (ESO) — during a campaign by the Event Horizon Telescope (EHT) Collaboration to image black holes. In April 2017 the EHT linked together eight existing radio telescopes worldwide, including ALMA, resulting in the recently released first ever image of Sagittarius A*. To calibrate the EHT data, Wielgus and his colleagues, who are members of the EHT Collaboration, used ALMA data recorded simultaneously with the EHT observations of Sagittarius A*. To the team’s surprise, there were more clues to the nature of the black hole hidden in the ALMA-only measurements.
By chance, some of the observations were done shortly after a burst or flare of X-ray energy was emitted from the centre of our galaxy, which was spotted by NASA’s Chandra Space Telescope. These kinds of flares, previously observed with X-ray and infrared telescopes, are thought to be associated with so-called ‘hot spots’, hot gas bubbles that orbit very fast and close to the black hole.
“What is really new and interesting is that such flares were so far only clearly present in X-ray and infrared observations of Sagittarius A*. Here we see for the first time a very strong indication that orbiting hot spots are also present in radio observations,”
says Wielgus, who is also affiliated with the Nicolaus Copernicus Astronomical Centre, Poland and the Black Hole Initiative at Harvard University, USA.
“Perhaps these hot spots detected at infrared wavelengths are a manifestation of the same physical phenomenon: as infrared-emitting hot spots cool down, they become visible at longer wavelengths, like the ones observed by ALMA and the EHT,”
adds Jesse Vos, a PhD student at Radboud University, the Netherlands, who was also involved in this study.
The flares were long thought to originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A*, and the new findings support this idea.
“Now we find strong evidence for a magnetic origin of these flares and our observations give us a clue about the geometry of the process. The new data are extremely helpful for building a theoretical interpretation of these events,”
says co-author Monika Mościbrodzka from Radboud University.
This visible light wide-field view shows the rich star clouds in the constellation of Sagittarius (the Archer) in the direction of the centre of our Milky Way galaxy. The entire image is filled with vast numbers of stars — but far more remain hidden behind clouds of dust and are only revealed in infrared images. This view was created from photographs in red and blue light and form part of the Digitized Sky Survey 2. The field of view is approximately 3.5 degrees x 3.6 degrees. Credits: ESO
ALMA allows astronomers to study polarised radio emission from Sagittarius A*, which can be used to unveil the black hole’s magnetic field. The team used these observations together with theoretical models to learn more about the formation of the hot spot and the environment it is embedded in, including the magnetic field around Sagittarius A*. Their research provides stronger constraints on the shape of this magnetic field than previous observations, helping astronomers uncover the nature of our black hole and its surroundings.
The observations confirm some of the previous discoveries made by the GRAVITY instrument at ESO’s Very Large Telescope (VLT), which observes in the infrared. The data from GRAVITY and ALMA both suggest the flare originates in a clump of gas swirling around the black hole at about 30% of the speed of light in a clockwise direction in the sky, with the orbit of the hot spot being nearly face-on.
“In the future we should be able to track hot spots across frequencies using coordinated multiwavelength observations with both GRAVITY and ALMA — the success of such an endeavour would be a true milestone for our understanding of the physics of flares in the Galactic centre,”
says Ivan Marti-Vidal of the University of València in Spain, co-author of the study.
The team is also hoping to be able to directly observe the orbiting gas clumps with the EHT, to probe ever closer to the black hole and learn more about it.
“Hopefully, one day, we will be comfortable saying that we ‘know’ what is going on in Sagittarius A*,”
Wielgus concludes.
This image shows the Atacama Large Millimeter/submillimeter Array (ALMA) looking up at the Milky Way as well as the location of Sagittarius A*, the supermassive black hole at our galactic centre. Highlighted in the box is the image of Sagittarius A* taken by the Event Horizon Telescope (EHT) Collaboration. Located in the Atacama Desert in Chile, ALMA is the most sensitive of all the observatories in the EHT array, and ESO is a co-owner of ALMA on behalf of its European Member States. Credits: ESO
