** What’s Up: July 2023 Skywatching Tips from NASA – NASA JPL
What are some skywatching highlights in July 2023?
Mars and Venus start the month close together, but part ways and head lower as July goes on. Mars appears very near Regulus in Leo on the 9th and 10th. Saturn and Jupiter rule the night, along with bright star Fomalhaut. And July is prime time for viewing the Milky Way core from dark sky locations.
0:00 Intro 0:12 Mars & Venus in the evening 0:31 Mars close to Regulus 1:07 Saturn & Jupiter in the morning 1:49 Fomalhaut’s debris disk 2:38 Viewing the Milky Way 3:17 July 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 July, find the Scorpius constellation to identify the reddish supergiant Antares, which will lead you to discover a trio of globular star clusters. Keep watching for space-based views of these densely packed, spherical collections of ancient stars, as well as three nebulas: the Swan Nebula, the Lagoon Nebula, and the Trifid Nebula.
Pete Lawrence and Paul Abel reveal what’s visible in the night sky this month, including Mercury and Venus, a (somewhat) brightening Jupiter, the Perseid meteor shower, minor planet Vesta, and Comet C/2020 V2 (ZTF).
Our monthly Sky Tour #astronomy #podcast provides an informative and entertaining 10-minute guided tour of the nighttime sky. Listen to the July episode and take the measure of #Earth’s orbit; track down #mars, #mercury, and #venus, and take a poke at the celestial scorpion, #scorpious.
Listen and subscribe to this podcast at https://skyandtelescope.org/observing/ and don’t forget to subscribe to S&T’s YouTube channel to get alerts about new videos, including this monthly podcast.
** What’s Up: June 2023 Skywatching Tips from NASA – NASA JPL
What are some skywatching highlights in June 2023? Mars and Venus draw closer throughout the month, while Saturn leads Jupiter into the morning sky. Bright stars Spica and Arcturus shine brightly overhead on June evenings, along with the Summer Triangle. And the June solstice, on the 21st, has a special claim to fame.
0:00 Intro 0:13 Mars & Venus in the evening 1:00 Saturn & Jupiter in the morning 1:19 Bright stars of June 2:22 June solstice 3:42 June 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….
Though the nights are shorter in June, they are filled with fine sights. Look for the Hercules constellation, which will lead you to a globular star cluster with hundreds of thousands of densely packed stars. You can also spot Draco the dragon, which will point you to the Cat’s Eye Nebula. Keep watching for space-based views of globular star clusters and the nebula.
Pete Lawrence and Paul Abel reveal what you can see in the night sky this month, including Mars, Venus and the Beehive Cluster, the Summer Solstice and the Summer Triangle.
Our monthly Sky Tour #astronomy #podcast provides an informative and entertaining 10-minute guided tour of the nighttime sky. Listen to the June episode and mark the Sun’s #solstice; follow the #Moon through its phases; watch #Venus and #Mars dance in the evening sky; track down a couple of faint #constellations; and shine a spotlight on the #star #Arcturus.
Using ESO’s Very Large Telescope (VLT), researchers have found for the first time the fingerprints left by the explosion of the first stars in the Universe. They detected three distant gas clouds whose chemical composition matches what we expect from the first stellar explosions. These findings bring us one step closer to understanding the nature of the first stars that formed after the Big Bang.
“For the first time ever, we were able to identify the chemical traces of the explosions of the first stars in very distant gas clouds,”
says Andrea Saccardi, a PhD student at the Observatoire de Paris – PSL, who led this study during his master’s thesis at the University of Florence.
Researchers think that the first stars that formed in the Universe were very different from the ones we see today. When they appeared 13.5 billion years ago, they contained just hydrogen and helium, the simplest chemical elements in nature [1]. These stars, thought to be tens or hundreds of times more massive than our Sun, quickly died in powerful explosions known as supernovae, enriching the surrounding gas with heavier elements for the first time. Later generations of stars were born out of that enriched gas, and in turn ejected heavier elements as they too died. But the very first stars are now long gone, so how can researchers learn more about them?
“Primordial stars can be studied indirectly by detecting the chemical elements they dispersed in their environment after their death,”
says Stefania Salvadori, Associate Professor at the University of Florence and co-author of the study published today in the Astrophysical Journal.
Using data taken with ESO’s VLT in Chile, the team found three very distant gas clouds, seen when the Universe was just 10–15% of its current age, and with a chemical fingerprint matching what we expect from the explosions of the first stars. Depending on the mass of these early stars and the energy of their explosions, these first supernovae released different chemical elements such as carbon, oxygen and magnesium, which are present in the outer layers of stars. But some of these explosions were not energetic enough to expel heavier elements like iron, which is found only in the cores of stars. To search for the telltale sign of these very first stars that exploded as low energy supernovae, the team therefore looked for distant gas clouds poor in iron but rich in the other elements. And they found just that: three faraway clouds in the early Universe with very little iron but plenty of carbon and other elements — the fingerprint of the explosions of the very first stars.
This peculiar chemical composition has also been observed in many old stars in our own galaxy, which researchers consider to be second-generation stars that formed directly from the ‘ashes’ of the first ones. This new study has found such ashes in the early Universe, thus adding a missing piece to this puzzle.
“Our discovery opens new avenues to indirectly study the nature of the first stars, fully complementing studies of stars in our galaxy,”
explains Salvadori.
To detect and study these distant gas clouds, the team used light beacons known as quasars — very bright sources powered by supermassive black holes at the centres of faraway galaxies. As the light from a quasar travels through the Universe, it passes through gas clouds where different chemical elements leave an imprint on the light.
To find these chemical imprints, the team analysed data on several quasars observed with the X-shooter instrument on ESO’s VLT. X-shooter splits light into an extremely wide range of wavelengths, or colours, which makes it a unique instrument with which to identify many different chemical elements in these distant clouds.
This study opens new windows for next generation telescopes and instruments, like ESO’s upcoming Extremely Large Telescope (ELT) and its high-resolution ArmazoNes high Dispersion Echelle Spectrograph (ANDES).
“With ANDES at the ELT we will be able to study many of these rare gas clouds in greater detail, and we will be able to finally uncover the mysterious nature of the first stars,”
concludes Valentina D’Odorico, a researcher at the National Institute of Astrophysics in Italy and co-author of the study.
Notes
[1] Minutes after the Big Bang the only elements present in the Universe were the three lightest ones: hydrogen, helium and very small traces of lithium. Heavier elements were formed much later on in stars.
** What’s Up: May 2023 Skywatching Tips from NASA – NASA JPL
What are some skywatching highlights in May 2023?
Venus reaches its highest point in the evening sky for the year, while Jupiter disappears behind the Moon for some U.S. observers. Plus, some key differences in the Southern Hemisphere’s skies compared to those of the North.
0:00 Intro 0:12 Moon & planet pairings 1:16 Venus at its highest 1:38 Skies of the Southern Hemisphere 3:48 May 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 May, we are looking away from the crowded, dusty plane of our own galaxy toward a region where the sky is brimming with distant galaxies. Locate Virgo to find a concentration of roughly 2,000 galaxies and search for Coma Berenices to identify many more. Keep watching for space-based views of galaxies like the Sombrero Galaxy, M87, and M64.
Astronomers Pete Lawrence and Paul Abel reveal the best things to see in the night sky this month, including catching Venus before it disappears, the daytime lunar occultation of Jupiter, the Moon and the tongue-twisting stars of Libra!
Our monthly Sky Tour #astronomy #podcast provides an informative and entertaining 10-minute guided tour of the nighttime sky. Listen to the May episode and look for tiny bits of #halleyscomet; watch the #Moon cover up #Jupiter; track down a couple of evening #planets; and take stock of bright #stars in the late-spring sky.
** What’s Up: April 2023 Skywatching Tips from NASA – NASA JPL
Mercury reaches its highest in the evening sky for the year for Northern Hemisphere observers. The Moon makes its monthly rounds to pair up beautifully with several planets. And viewing conditions may be ideal for the annual Lyrid meteor shower, thanks to no interference from the Moon.
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….
Clear April nights are filled with starry creatures. Near the Big Dipper, you will find several interesting binary stars. You can also spot galaxies like the Pinwheel Galaxy, M82, and M96—the last of which is an asymmetric galaxy that may have been gravitationally disrupted by encounters with its neighbors. Keep watching for space-based views of these celestial objects.
… “Tonight’s Sky” is a monthly video of constellations you can observe in the night sky. The series is produced by the Space Telescope Science Institute, home of science operations for the Hubble Space Telescope, in partnership with NASA’s Universe of Learning. This is a recurring show, and you can find more episodes—and other astronomy videos—at https://hubblesite.org/resource-galle….
What’s in the night sky tonight? Astronomers Pete Lawrence and Paul Abel guide us through April’s night-sky highlights, including Mercury’s favourable position in the evening sky, a wonderful encounter between Venus and the Pleiades, Mars in Gemini and the Lyrid meteor shower.
Our monthly Sky Tour #astronomy #podcast provides an informative and entertaining 10-minute guided tour of the nighttime sky. Listen to the April episode and follow the #Moon around the sky; spot #Venus and #Mercury soon after #sunset; track down a hunter, a lion, a bear, a snake, and a crow; and watch for the #Lyrids, a modest meteor shower toward month’s end.