AEA Astronomy Club Newsletter July 2021

Contents

AEA Astronomy Club News & Calendar p.1
Video(s) & Picture(s) of the Month p. 2
Astronomy News p. 11
General Calendar p. 15

Colloquia, lectures, mtgs. p. 15
Observing p. 18

Useful Links p. 20
About the Club p. 21

Club News & Calendar.

Club Calendar

Club Meeting Schedule: --

1 July

AEA

TBD

(A1/1735)

AEA Astronomy Club Meeting

TBD -- Great Courses video

Teams

5 Aug

AEA

TBD

(A1/1735)

AEA Astronomy Club Meeting

TBD -- Great Courses video

Teams

AEA Astronomy Club meetings are now on 1^st Thursdays at 11:30 am. For 2020: Jan. & Feb. in A1/1735, March 5 in A1/2906 and for the rest of 2020 (April to Dec.) virtual meetings on Teams.

Club News:

We have made reservations for a night on the Mt. Wilson 60” (Oct. 2) and 100” (Oct. 30). We will need to decide which. Those on the list for last year’s 100-inch night that was cancelled due to COVID have first priority if they’d like to do the 100-inch or 60-inch. There may be new openings, so we can take new names, at least for a wait list.

Contact Jason Fields if interested in joining him for an observing night with his 20” Dobs.

We need volunteers to help with:

· Assembling our new 16-inch Hubble Optics Dobs

· Installing our new software on our tablet & laptop

· Populating our club Sharepoint site with material & links to the club’s Aerowiki & Aerolink materials – Kaly Rangarajan has volunteered to help with this

· Arranging future club programs

· Managing club equipment & library (Kelly Gov volunteered to help with the library)

Astronomy Video(s) & Picture(s) of the Month

(generally from Astronomy Picture of the Day, APOD: http://apod.nasa.gov/apod/archivepix.html)

VIDEO: Simulation: Formation of the First Stars https://apod.nasa.gov/apod/ap210630.html
Video Credit: Harley Katz (U. Oxford) et al.

Explanation: How did the first stars form? To help find out, the SPHINX computer simulation of star formation in the very early universe was created, some results of which are shown in the featured video. Time since the Big Bang is shown in millions of years on the upper left. Even 100 million years after the Big Bang, matter was spread too uniformly across the cosmos for stars to be born. Besides background radiation, the universe was dark. Soon, slight matter clumps rich in hydrogen gas begin to coalesce into the first stars. In the time-lapse video, purple denotes gas, white denotes light, and gold shows radiation so energetic that it ionizes hydrogen, breaking it up into charged electrons and protons. The gold-colored regions also track the most massive stars that die with powerful supernovas. The inset circle highlights a central region that is becoming a galaxy. The simulation continues until the universe was about 550 million years old. To assess the accuracy of the SPHINX simulations and the assumptions that went into them, the results are not only being compared to current deep observations, but will also be compared with more direct observations of the early universe planned with NASA's pending James Webb Space Telescope.

VIDEO: STARFORGE: A Star Formation Simulation https://apod.nasa.gov/apod/ap210623.html
Video & Text Credit: Michael Y. Grudić (Northwestern U.) et al., STARFORGE Collaboration;
Music: Prelude, Op. 28, No. 4 in E Minor (Frédéric Chopin)

Explanation: How do stars form? Most form in giant molecular clouds located in the central disk of a galaxy. The process is started, influenced, and limited by the stellar winds, jets, high energy starlight, and supernova explosions of previously existing stars. The featured video shows these complex interactions as computed by the STARFORGE simulation of a gas cloud 20,000 times the mass of our Sun. In the time-lapse visualization, lighter regions indicate denser gas, color encodes the gas speed (purple is slow, orange is fast), while dots indicate the positions of newly formed stars. As the video begins, a gas cloud spanning about 50 light years begins to condense under its own gravity. Within 2 million years, the first stars form, while newly formed massive stars are seen to expel impressive jets. The simulation is frozen after 4.3 million years, and the volume then rotated to gain a three-dimensional perspective. Much remains unknown about star formation, including the effect of the jets in limiting the masses of subsequently formed stars

Satellites over Orion
Image Credit: Amir H. Abolfath

Explanation: What are those streaks across Orion? They are reflections of sunlight from numerous Earth-orbiting satellites. Appearing by eye as a series of successive points floating across a twilight sky, the increasing number of communications satellites, including SpaceX Starlink satellites, are causing concern among many astronomers. On the positive side, Starlink and similar constellations make the post-sunset sky more dynamic, satellite-based global communications faster, and help provide digital services to currently underserved rural areas. On the negative side, though, these low Earth-orbit satellites make some deep astronomical imaging programs more difficult, in particular observing programs that need images taken just after sunset and just before dawn. Planned future satellite arrays that function in higher orbits may impact investigations of the deep universe planned for large ground-based telescopes at any time during the night. The streaks across Orion are not from Starlink but rather satellites in high geosynchronous orbit. The featured picture, taken in 2019 December, is a digital combination of over 65 3-minutes exposures, with some images taken to highlight the background Orion Nebula, while others to feature the passing satellites.

Orion Nebula: The Hubble View
Image Credit: NASA, ESA, Hubble Legacy Archive; Processing: Francisco Javier Pobes Serrano

Explanation: Few cosmic vistas excite the imagination like the Orion Nebula. Also known as M42, the nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. The Orion Nebula offers one of the best opportunities to study how stars are born partly because it is the nearest large star-forming region, but also because the nebula's energetic stars have blown away obscuring gas and dust clouds that would otherwise block our view - providing an intimate look at a range of ongoing stages of starbirth and evolution. The featured image of the Orion Nebula is among the sharpest ever, constructed using data from the Hubble Space Telescope. The entire Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun.

HD 163296: Jet from a Star in Formation
Image Credit: Visible: VLT/MUSE (ESO); Radio: ALMA (ESO/NAOJ/NRAO)

Explanation: How are jets created during star formation? No one is sure, although recent images of the young star system HD 163296 are quite illuminating. The central star in the featured image is still forming but seen already surrounded by a rotating disk and an outward moving jet. The disk is shown in radio waves taken by the Atacama Large Millimeter Array (ALMA) in Chile, and show gaps likely created by the gravity of very-young planets. The jet, shown in visible light taken by the Very Large Telescope (VLT, also in Chile), expels fast-moving gas -- mostly hydrogen -- from the disk center. The system spans hundreds of times the Earth-Sun distance (au). Details of these new observations are being interpreted to bolster conjectures that the jets are generated and shaped, at least in part, by magnetic fields in the rotating disk. Future observations of HD 163296 and other similar star-forming systems may help fill in details.

Sunrise Solstice over Stonehenge
Image Credit & Copyright: Max Alexander, STFC, SPL

Explanation: Today the Sun reaches its northernmost point in planet Earth's sky. Called a solstice, many cultures mark this date as a change of seasons -- from spring to summer in Earth's Northern Hemisphere and from fall to winter in Earth's Southern Hemisphere. Precisely, the single time of solstice occurs today for some parts of the world, but tomorrow for other regions. The featured image was taken during the week of the 2008 summer solstice at Stonehenge in United Kingdom, and captures a picturesque sunrise involving fog, trees, clouds, stones placed about 4,500 years ago, and a 4.5 billion year old large glowing orb. Even given the precession of the Earth's rotational axis over the millennia, the Sun continues to rise over Stonehenge in an astronomically significant way.

Zhurong: New Rover on Mars
Image Credit: China National Space Administration

Explanation: There's a new rover on Mars. In mid-May, China's Tianwen-1 mission delivered the Zhurong rover onto the red planet. As Mars means Planet of Fire in Chinese, the Zhurong rover's name means, roughly, God of Fire in Chinese mythology. Zhurong landed in northern Utopia Planitia, the largest known impact basin in the Solar System, and an area reported to have much underground ice. Among many other scientific instruments, Zhurong carries ground-penetrating radar that can detect ice buried even 100-meters deep. Car-sized Zhurong is pictured here next to its landing base. The image was snapped by a remote camera deployed by the rolling rover. Zhurong's planned 90-day mission includes studying the geology, soil, and atmosphere of Mars in Utopia Planitia.

Ganymede from Juno
Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Processing & License: Kevin M. Gill;

Explanation: What does the largest moon in the Solar System look like? Jupiter's moon Ganymede, larger than even Mercury and Pluto, has an icy surface speckled with bright young craters overlying a mixture of older, darker, more cratered terrain laced with grooves and ridges. The cause of the grooved terrain remains a topic of research, with a leading hypothesis relating it to shifting ice plates. Ganymede is thought to have an ocean layer that contains more water than Earth -- and might contain life. Like Earth's Moon, Ganymede keeps the same face towards its central planet, in this case Jupiter. The featured image was captured last week by NASA's robotic Juno spacecraft as it passed only about 1000 kilometers above the immense moon. The close pass reduced Juno's orbital period around Jupiter from 53 days to 43 days. Juno continues to study the giant planet's high gravity, unusual magnetic field, and complex cloud structures.

Millions of Stars in Omega Centauri
Image Credit & Copyright: Ignacio Diaz Bobillo

Explanation: Globular star cluster Omega Centauri, also known as NGC 5139, is some 15,000 light-years away. The cluster is packed with about 10 million stars much older than the Sun within a volume about 150 light-years in diameter. It's the largest and brightest of 200 or so known globular clusters that roam the halo of our Milky Way galaxy. Though most star clusters consist of stars with the same age and composition, the enigmatic Omega Cen exhibits the presence of different stellar populations with a spread of ages and chemical abundances. In fact, Omega Cen may be the remnant core of a small galaxy merging with the Milky Way. Omega Centauri's red giant stars (with a yellowish hue) are easy to pick out in this sharp, color telescopic view.

The Galactic Center in Stars, Gas, and Magnetism
Image Credit: X-ray: NASA/CXC/UMass/Q.D. Wang; Radio: NRF/SARAO/MeerKAT

Explanation: What's going on near the center of our galaxy? To help find out, a newly detailed panorama has been composed that explores regions just above and below the galactic plane in radio and X-ray light. X-ray light taken by the orbiting Chandra Observatory is shown in orange (hot), green (hotter), and purple (hottest) and superposed with a highly detailed image in radio waves, shown in gray, acquired by the MeerKAT array. Interactions are numerous and complex. Galactic beasts such as expanding supernova remnants, hot winds from newly formed stars, unusually strong and colliding magnetic fields, and a central supermassive black hole are all battling in a space only 1000 light years across. Thin bright stripes appear to result from twisting and newly connecting magnetic fields in colliding regions, creating an energetic type of inner galactic space weather with similarities to that created by our Sun. Continued observations and study hold promise to not only shed more light on the history and evolution of our own galaxy -- but all galaxies.

Astronomy News:

From ScienceNews.org

An arc of galaxies 3 billion light-years long may

challenge cosmology

The discovery is a “big deal” if true, but still needs to be confirmed

Observations of thousands of galaxies taken by the Sloan Digital Sky Survey (pictured) helped reveal a purported giant arc of galaxies, more than 3 billion light-years long.

PATRICK GAULME/SLOAN DIGITAL SKY SURVEY (CC BY 4.0)

By Lisa Grossman

JUNE 10, 2021 AT 2:01 PM

UPDATED JUNE 10, 2021 AT 4:15 PM

A giant arc of galaxies appears to stretch across more than 3 billion light-years in the distant universe. If the arc turns out to be real, it would challenge a bedrock assumption of cosmology: that on large scales, matter in the universe is evenly distributed no matter where you look.

“It would overturn cosmology as we know it,” said cosmologist Alexia Lopez at a June 7 news conference at the virtual American Astronomical Society meeting. “Our standard model, not to put it too heavily, kind of falls through.”

Lopez, of the University of Central Lancashire in Preston, England, and colleagues discovered the purported structure, which they call simply the Giant Arc, by studying the light of about 40,000 quasars captured by the Sloan Digital Sky Survey. Quasars are the luminous cores of giant galaxies so distant that they appear as points of light. While en route to Earth, some of that light gets absorbed by atoms in and around foreground galaxies, leaving specific signatures in the light that eventually reaches astronomers’ telescopes (SN: 7/12/18).

The Giant Arc’s signature is in magnesium atoms that have lost one electron, in the halos of galaxies about 9.2 billion light-years away. The quasar light absorbed by those atoms traces out a nearly symmetrical curve of dozens of galaxies spanning about one-fifteenth the radius of the observable universe, Lopez reported. The structure itself is invisible on the sky to human eyes, but if you could see it, the arc would span about 20 times the width of the full moon.

Astronomers discovered what they say is a giant arc of galaxies (smile-shaped curve in the middle of this image) by using the light from distant quasars (blue dots) to map out where in the sky that light got absorbed by magnesium atoms in the halos (dark spots) that surround foreground galaxies.A. LOPEZ

“This is a very fundamental test of the hypothesis that the universe is homogeneous on large scales,” says astrophysicist Subir Sarkar of the University of Oxford, who studies large-scale structures in the universe but was not involved in the new work. If the Giant Arc is real, “this is a very big deal.”

But Sarkar isn’t convinced it is real yet. “Our eye has a tendency to pick up patterns,” Sarkar says, noting that some people have claimed to see cosmologist Stephen Hawking’s initials written in fluctuations in the cosmic microwave background, the oldest light in the universe.

Lopez ran three statistical tests to figure out the odds that galaxies would line up in a giant arc by chance. All three suggest that the structure is real, with one test surpassing physicists’ gold standard that the odds of it being a statistical fluke are less than 0.00003 percent.

That sounds pretty good, but it may not be enough, Sarkar says. “Right now, I would say the evidence is tantalizing but not yet compelling,” he says. More observations, from Lopez’s group and others, could confirm or refute the Giant Arc.

If it is real, the Giant Arc would join a growing group of large-scale structures in the universe that, taken together, would break the standard model of cosmology. This model assumes that when you look at large enough volumes of space — above about 1 billion light-years — matter is distributed evenly. The Giant Arc appears about three times as long as that theoretical threshold. It joins other structures with similarly superlative names, like the Sloan Great Wall, the Giant Gamma-Ray Burst Ring and the Huge Large Quasar Group.

“We can have one large-scale structure that could just be a statistical fluke,” Lopez said. “That’s not the problem. All of them combined is what makes the problem even bigger.”

Questions or comments on this article? E-mail us at feedback@sciencenews.org

Editor's Note:

This story was updated June 10, 2021, to clarify the description of the statistical tests, and on June 11, 2021, to correct the description of Sarkar's opinion of the work.

CITATIONS

A. Lopez. A Giant Arc on the sky. American Astronomical Society meeting. June 7, 2021.

Souped-up supernovas may produce much of the universe’s heavy elements

Analysis of a rare, ancient star suggests a new birthplace for elements like uranium and silver

Explosions of massive, magnetized stars (similar to the one illustrated) may be the source of much of the universe’s heavy elements.

ANNA SERENA ESPOSITO

By Mara Johnson-Groh

JULY 7, 2021 AT 12:10 PM

Violent explosions of massive, magnetized stars may forge most of the universe’s heavy elements, such as silver and uranium.

These r-process elements, which include half of all elements heavier than iron, are also produced when neutron stars merge (SN: 10/16/17). But collisions of those dead stars alone can’t form all of the r-process elements seen in the universe. Now, scientists have pinpointed a type of energetic supernova called a magnetorotational hypernova as another potential birthplace of these elements.

The results, described July 7 in Nature, stem from the discovery of an elderly red giant star — possibly 13 billion years old — in the Milky Way’s halo (SN: 1/9/20). By analyzing the star’s elemental makeup, which is like a star’s genetic instruction book, astronomers peered back into the star’s family history. Forty-four different elements seen in the star suggest that it was formed from material left over “by a special explosion of one massive star soon after the Big Bang,” says astronomer David Yong of the Australian National University in Canberra.

The ancient star’s elements aren’t from the remnants of a neutron star merger, Yong and his colleagues say. Its abundances of certain heavy elements such as thorium and uranium were higher than would be expected from a neutron star merger. Additionally, the star also contains lighter elements such as zinc and nitrogen, which can’t be produced by those mergers. And since the star is extremely deficient in iron — an element that builds up over many stellar births and deaths — the scientists think that the red giant is a second-generation star whose heavy elements all came from one predecessor supernova-type event.

Magnetorotational hypernovas might be similar to collapsars — massive, spinning stars that collapse into black holes instead of exploding. Collapsars have previously been proposed as birthplaces of r-process elements, too (SN: 5/8/19).

The researchers think that magnetorotational hypernovas are rare, composing only 1 in 1,000 supernovas. Even so, such explosions would be 10 times as common as neutron star mergers today, and would produce similar amounts of heavy elements per event. Along with their less energetic counterparts, called magnetorotational supernovas, these hypernovas could be responsible for creating 90 percent of all r-process elements, coauthor Chiaki Kobayashi, an astrophysicist at the University of Hertfordshire in Hatfield, England, had previously calculated. In the early universe, when massive, rapidly rotating stars were more common, such explosions could have been even more influential.

The observations are impressive, says Stan Woosley, an astrophysicist at the University of California, Santa Cruz, who was not involved in the new study. But “there is no proof that the [elemental] abundances in this metal-deficient star were made in a single event. It could have been one. It could have been 10.” One of those events might even have been a neutron star merger, he says.

The scientists hope to find more stars like the elderly red giant, which could reveal how frequent magnetorotational hypernovas are. For now, the newly analyzed star remains “incredibly rare and demonstrates the need for … large surveys to find such objects,” Yong says.

General Calendar:

Colloquia, Lectures, Seminars, Meetings, Open Houses & Tours:

Colloquia: Carnegie (Tues. 4pm), UCLA, Caltech (Wed. 4pm), IPAC (Wed. 12:15pm) & other Pasadena

(daily 12-4pm): http://obs.carnegiescience.edu/seminars/

Carnegie Zoom Digital Series

Zoom Webinar Platform

A Virtual Conversation with Materials Physicist Sally Tracy

Friday, July 9, 2021 - 3:30pm to 4:30pm

Timezone:

Join us to learn about materials physics from Carnegie scientist Sally Tracy. Tracy uses cutting-edge experimental and analytical techniques to understand the fundamental physical behavior of materials at extreme conditions.

She uses dynamic compression techniques with high-flux X-ray sources to probe the structural changes and phase transitions in materials at conditions that mimic impacts and the interiors of terrestrial and exoplanets. She is also an expert in nuclear resonant scattering and synchrotron X-ray diffraction. She uses these techniques to understand novel behavior at the electronic level. Tracy received her Ph.D. from the California Institute of Technology in 2016 and was then a Postdoctoral Scholar at Princeton University prior to arriving at Carnegie's Geophysical Laboratory.

Zoom Digital Platform

United States

A Virtual Conversation with Cell Biologist Brittany Belin

Wednesday, July 21, 2021 - 3:00pm to 4:00pm

Timezone:

Join us to learn about cell biology from Carnegie scientist Brittany Belin.

Over-reliance on synthetic fertilizers for crop plants can have disastrous environmental consequences. A natural and sustainable alternative to this practice is the application of microbes that can help plants better access the nutrients in their environment. A major category of plant-fertilizing microbes contains the rhizobia, soil bacteria that can sustainably provide nitrogen fertilizer to legumes, including major commercial crops such as soybeans and peanuts, cover crops such as alfalfa and clovers, and leguminous trees such as acacias. Dr. Belin uses diverse quantitative microscopy and modeling approaches to understand the cell biology of rhizobia and other nitrogen-fixing bacteria, and the genetic factors that drive their productive interactions with plant hosts.

Zoom Webinar Platform,

July Night Sky Network Clubs & Events https://nightsky.jpl.nasa.gov/clubs-and-events.cfm

1 July

AEA

TBD

(A1/1735)

AEA Astronomy Club Meeting

TBD -- Great Courses video

Teams

Cancelled for now

Friday Night 7:30PM SBAS Monthly General Meeting

in the Planetarium at El Camino College (16007 Crenshaw Bl. In Torrance)

July 22 The von Kármán Lecture Series: 2021

Science + Art: Picturing Discovery

Time: 7 p.m. PDT (10 p.m. EDT; 0300 UTC)

A scientist and an artist walk into a room… In this STEAM inspired chat, we’ll discuss how science influences art and art, in turn, influences science. We’ll discuss how JPL artists collaborate with scientists to create artistic renderings of scientific discoveries and how artists take information and enhance it through data visualization.

Speaker(s):
Morgan Cable, Ocean World Astrochemist, NASA/JPL
Joby Harris, Visual Strategist, NASA/JPL

Host:
Brian White, Public Services Office, NASA/JPL

Co-Host:
Nikki Wyrick, Public Services Office, NASA/JPL

Webcast:
Click here to watch the event live on YouTube
Click here to watch the event live on Ustream

Past shows are archived on YouTube.

Click here for the YouTube playlist of past shows

12 July

LAAS General Mtg. 7:30pm Griffith Observatory (private)

June 20

UCLA METEORITE SCIENTISTS

No event shown this month, but see their 2021 poetry contest for some good stuff – I liked the 3^rd place “Ballad of Meteorite John” – reminded me of “The Cremation of Sam McGee.”

https://meteorites.ucla.edu/events/

5 Aug

AEA Astronomy Club Meeting

TBD -- Great Courses video

(Teams)

Observing:

The following data are from the 2021 Observer’s Handbook, and Sky & Telescope’s 2021 Skygazer’s Almanac & monthly Sky at a Glance.

Current sun & moon rise/set/phase data for L.A.: http://www.timeanddate.com/astronomy/usa/los-angeles

Sun, Moon & Planets for July:

Moon: July 1 last quarter, July 10 new, July 17 1^st quarter, July 24 Full, July 31 last quarter

Planets (June): Venus is shines brightly at dusk all month. Mars is visible at dusk and sets in the late evening. Jupiter and Saturn rise in the evening and are visible through dawn, Mercury is visible at dawn until the 23rd.

Other Events:

LAAS Event Calendar (incl. various other virtual events):

https://www.laas.org/laas-bulletin/#calendar

Cancelled

LAAS The Garvey Ranch Observatory is open to the public every Wednesday evening from 7:30 PM to 10 PM. Go into the dome to use the 8 Inch Refractor or observe through one of our telescopes on the lawn. Visit our workshop to learn how you can build your own telescope, grind your own mirror, or sign up for our free seasonal astronomy classes.

Call 213-673-7355 for further information.

Time: 7:30 PM - 10:00 PM

Location: Garvey Ranch Obs. , 781 Orange Ave., Monterey Park, CA 91755

3 July

SBAS In-town observing session – In Town Dark Sky Observing Session at Ridgecrest Middle School– 28915 NortbBay Rd. RPV, Weather Permitting: Please contact Ken Munson to confirm that the gate will be opened. http://www.sbastro.net/. Only if we get permission to use the school grounds again and CDC guidelines are reduced

4 July Mercury greatest elongation W (22deg)

10 July	SBAS out-of-town Dark Sky observing – contact Ken Munson to coordinate a location. http://www.sbastro.net/.
10 July	LAAS Private dark sky Star Party

12 July Venus 3deg S of Moon

13 July Venus 0.5deg N of Mars

Cancelled

LAAS Public Star Party: Griffith Observatory Grounds 2-10pm See http://www.griffithobservatory.org/programs/publictelescopes.html#starparties for more information.

29 July Southern Delta Aquariids Meteor Shower Peak The Southern Delta Aquariids are a meteor shower visible from mid-July to midAugust each year with peak activity on 28 or 29 July. The Comet of origin is not known with certainty. Suspected candidate is Comet 96P Machholz. Earlier, it was thought to have originated from the Marsden and Kracht Sungrazing comets. Zenithal Hourly Rate is nominally about 16.

Internet Links: