AEA Astronomy Club Newsletter February 2022
Contents
AEA Astronomy Club News & Calendar p.1
Video(s) & Picture(s) of the Month p. 1
Astronomy News p. 9
General Calendar p. 15
Colloquia, lectures, mtgs. p. 15
Observing p. 17
Useful
Links p. 18
About the Club p.
19
Club News &
Calendar.
AEA Astronomy Club
Newsletter February 2022
Contents
AEA Astronomy Club News & Calendar p.1
Video(s) & Picture(s) of the Month p. 1
Astronomy News p. 9
General Calendar p. 15
Colloquia, lectures, mtgs. p. 15
Observing p. 17
Useful Links p. 18
About the Club p. 19
Club News & Calendar.
Club Calendar
Club Meeting Schedule:
--
3 Feb AEA
Astronomy Club Meeting TBD – Great Courses
video Teams
3 Mar AEA
Astronomy Club Meeting TBD – Great Courses
video Teams
AEA
Astronomy Club meetings are now on 1st Thursdays at 11:30 am. Virtual meetings on Teams until further
notice. When live meetings resume, our
preferred room has been A1/1735, when we can reserve it.
Club
News:
Contact
Jason Fields if interested in joining him for an observing night with his 20”
Dobs.
We need volunteers to help with:
·
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, Sam has a fair chunk of the equipment)
Astronomy Video(s)
& Picture(s) of the Month
(generally from
Astronomy Picture of the Day, APOD: http://apod.nasa.gov/apod/archivepix.html)
Video: Comet Leonard over One Hour https://apod.nasa.gov/apod/ap220125.html
Video Credit & Copyright: Matipon Tangmatitham (NARIT); Text: Matipon Tangmatitham
Explanation: Which direction is this comet heading? Judging by the tail,
one might imagine that Comet Leonard is
traveling towards the bottom right, but a full 3D analysis shows it
traveling almost
directly away from the camera. With this perspective, the dust tail is
trailed towards the camera and can only be seen as a short yellow-white glow
near the head of the comet. The bluish ion tail, however, is
made up of escaping ions that are forced directly away from the Sun by
the solar
wind -- but channeled along the Sun's
magnetic field lines. The Sun's magnetic field is quite complex,
however, and occasionally solar
magnetic reconnection will break the ion tail into
knots that are pushed away from the Sun. One such knot is visible in the
featured one-hour time-lapse video captured in late December from Thailand. Comet Leonard is
now fading as it heads out of our
Solar System.
Video: Comet
Leonard's Tail Wag https://apod.nasa.gov/apod/ap220110.html
Image Credit: NASA, NRL, STEREO-A; Processing: B. Gallagher
Explanation: Why does Comet Leonard's tail wag? The featured time-lapse
video shows the ion tail of Comet C/2021 A1
(Leonard) as it changed over ten days early last month. The video was
taken by NASA's Solar
Terrestrial Relations Observatory-Ahead (STEREO-A) spacecraft that co-orbits the
Sun at roughly the same distance as the Earth. Each image in this
29-degree field was subtracted from following image to create frames that
highlight differences. The video clearly shows Comet Leonard's long ion tail
extending, wagging,
and otherwise being blown
around by the solar
wind -- a stream of fast-moving ions that stream out from
the Sun. Since the
video was taken, Comet
Leonard continued plunging toward the Sun, reached its closest
approach to the Sun between the orbits of Mercury and Venus, survived
this closest approach without breaking apart, and is now
fading as heads out of our Solar
System.
Hubble's Jupiter and the Shrinking Great Red Spot
Image Credit: NASA, ESA, Hubble, OPAL Program, STScI; Processing: Karol Masztalerz
Explanation: What will become of Jupiter's Great Red Spot? Gas
giant Jupiter is
the solar system's largest world with about 320 times the mass of
planet Earth. Jupiter is home to one of the largest and longest lasting
storm systems known, the Great
Red Spot (GRS), visible to the left. The GRS is so large it
could swallow Earth, although it has been shrinking. Comparison with historical
notes indicate that the
storm spans only about one third of the exposed surface area it had
150 years ago. NASA's Outer
Planets Atmospheres Legacy (OPAL) program has been monitoring the
storm more recently using the Hubble Space
Telescope. The featured
Hubble OPAL image shows Jupiter as it appeared
in 2016, processed in a way that makes red hues appear quite vibrant.
Modern GRS
data indicate that the storm continues to constrict its surface area,
but is also becoming slightly
taller, vertically. No one knows the future of the GRS, including the
possibility that if the shrinking trend continues, the GRS might one day even
do what smaller
spots on Jupiter have done -- disappear
completely.
A Year of Sunrises
Image Credit & Copyright: Luca Vanzella
Explanation: Does the Sun always rise in the same direction? No. As the
months change, the direction toward the rising Sun changes, too. The featured image shows
the direction of sunrise every month during 2021 as seen from the city of Edmonton, Alberta, Canada. The camera in the image
is always facing due east, with north toward the left and south toward the
right. As shown in an accompanying
video, the top image was taken in 2020 December, while the bottom image was
captured in 2021 December, making 13 images in total. Although the Sun
always rises in the east in general, it rises furthest to the south of
east near the December
solstice, and furthest north of east near the June solstice. In many
countries, the December
Solstice is considered an official change in season: for example the
first day of winter
in the North. Solar
heating and stored energy in the Earth's surface and atmosphere
are near their lowest during
winter, making the winter season the
coldest of the year.
Saturn, Tethys, Rings, and Shadows
Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation: Seen from ice
moon Tethys, rings and shadows would display fantastic views of the
Saturnian system. Haven't dropped in on Tethys
lately? Then this
gorgeous ringscape from the Cassini spacecraft will have to do for
now. Caught in sunlight just
below and left of picture center in 2005, Tethys itself is about 1,000
kilometers in diameter and orbits not quite five
saturn-radii from the center of the gas giant planet. At that distance
(around 300,000 kilometers) it is well outside Saturn's main bright rings, but
Tethys is still one of five
major moons that find themselves within the boundaries of the faint and tenuous
outer E ring.
Discovered in the 1980s, two very small moons Telesto and Calypso are
locked in stable along Tethys'
orbit. Telesto precedes and Calypso follows Tethys
as the trio circles
Saturn.
Image Credit & Copyright: Soumyadeep Mukherjee
Explanation: Every Full Moon of 2021 shines in this year-spanning astrophoto project, a composite portrait of the familiar lunar nearside at each brightest lunar phase. Arranged by moonth, the year progresses in stripes beginning at the top. Taken with the same camera and lens the stripes are from Full Moon images all combined at the same pixel scale. The stripes still look mismatched, but they show that the Full Moon's angular size changes throughout the year depending on its distance from Kolkata, India, planet Earth. The calendar month, a full moon name, distance in kilometers, and angular size is indicated for each stripe. Angular size is given in minutes of arc corresponding to 1/60th of a degree. The largest Full Moon is near a perigee or closest approach in May. The smallest is near an apogee, the most distant Full Moon in December. Of course the full moons of May and November also slid into Earth's shadow during 2021's two lunar eclipses.
Stars, Dust, and Gas Near Antares
Image Credit & Copyright: Mario Cogo (Galax Lux)
Explanation: Why is the sky near Antares and Rho Ophiuchi so
dusty yet colorful? The colors result from a mixture of objects and processes.
Fine dust -- illuminated from the front by starlight -- produces blue reflection nebulae.
Gaseous clouds whose atoms are excited by ultraviolet starlight
produce reddish emission
nebulae. Backlit dust clouds
block starlight and so appear
dark. Antares,
a red
supergiant and one of the brighter
stars in the night sky, lights up the yellow-red clouds on the lower right
of the featured
image. The Rho
Ophiuchi star system lies at the center of the blue reflection nebula on
the top left. The distant globular cluster of
stars M4 is
visible above and to the right of Antares. These star clouds are even
more colorful than humans can see,
emitting light across the electromagnetic
spectrum.
Young Star Jet MHO 2147
Image Credit & License: International
Gemini Observatory / NOIRLab /
NSF / AURA
Acknowledgments: L. Ferrero (Universidad Nacional de Córdoba)
Explanation: Laser guide
stars and adaptive optics
sharpened this stunning ground-based image of stellar jets from the Gemini South Observatory, Chilean Andes,
planet Earth. These twin
outflows of MHO 2147 are from a young star in formation. It
lies toward the central Milky Way and the boundary of the constellations
Sagittarius and Ophiuchus at an estimated distance of some 10,000 light-years.
At center, the star itself is obscured by a dense region of cold dust. But the
infrared image still traces the sinuous jets across a frame that would span about
5 light-years at the system's estimated distance. Driven outward by the young
rotating star, the apparent wandering direction of the jets is likely due to
precession. Part of a multiple star system, the young star's rotational axis
would slowly precess or wobble like a top under the gravitation influence of
its nearby companions.
NGC 7822 in Cepheus
Image Credit & Copyright: Mark Carter
Explanation: Hot, young stars and cosmic pillars of gas
and dust seem to crowd into NGC 7822. At the edge of a giant molecular cloud
toward the northern constellation Cepheus, the glowing star forming region lies
about 3,000 light-years away. Within the nebula, bright edges and dark shapes
stand out in this colorful telescopic skyscape. The
image includes data from narrowband filters,
mapping emission from atomic oxygen, hydrogen, and sulfur into blue, green, and
red hues. The emission line and color combination has become well-known as
the Hubble
palette. The atomic emission is powered by energetic
radiation from the central hot stars. Their powerful winds and radiation sculpt
and erode the denser pillar shapes and clear out a characteristic cavity
light-years across the center of the natal cloud. Stars could still be forming
inside the pillars by gravitational
collapse but as the pillars are eroded away, any forming stars will
ultimately be cutoff from their reservoir of star
stuff. This field of view spans about 40 light-years at the estimated
distance of NGC 7822.
Astronomy
News:
From
ScienceNews.org
The James
Webb Space Telescope has reached its new home at last
Next
on the to-do list: Cool down. Straighten out. Turn everything on. Take a look
around
The James Webb Space Telescope launched in a
compact, folded position, gradually unfurling in space. This artist’s
illustration shows the fully deployed spacecraft as it will look when it’s
ready to start observing the universe.
ADRIANA MANRIQUE GUTIERREZ/CIL/NASA GSFC
JaNUARY 24, 2022 AT 2:28 PM
The James Webb
Space Telescope has finally arrived at its new home. After a Christmas launch and
a month of unfolding and assembling itself in space, the new space observatory
reached its final destination, a spot known as L2.
There are
still several months’ worth of tasks on Webb’s to-do list before the telescope is ready to peep at the earliest
light in the universe or spy on exoplanets’ alien atmospheres (SN: 10/6/21).
“That doesn’t
mean there’s anything wrong,” says astronomer Scott Friedman of the Space
Telescope Science Institute in Baltimore, who is managing this next phase of
Webb’s journey. “Everything could go perfectly, and it would still take six
months” from launch for the telescope’s science instruments to be ready for
action, he says.
Here’s what to
expect next.
Life at L2
L2,
technically known as the second Earth-sun Lagrange point, is a spot about 1.5
million kilometers from Earth in the direction of Mars, where the sun and
Earth’s gravity balance out the inward-pulling centripetal force that keeps a
smaller object on a curved path. That lets objects at Lagrange points stay put
without much effort. Pairs of massive objects in space have five such Lagrange points.
The telescope, also known as JWST, isn’t just sitting tight, though. It’s orbiting L2, even as L2 orbits the sun. That’s because L2 is not precisely stable, Friedman says. It’s like trying to stay balanced directly on top of a basketball. If you nudged an object sitting exactly at that point, it would be easy to make it wander off. Circling L2 in 180 days as L2 circles the sun in a “halo orbit” is much more stable — it’s harder to fall off the basketball when in constant motion. But it takes some effort to stay there.
Webb
has one more feature that helps it stay stable. The telescope’s gigantic
kitelike sunshield, which protects the delicate instruments from the heat and
light of the sun, Earth and the moon, could pick up momentum from the stream of
charged particles that constantly flows from the sun, like a solar sail. If so,
that could push Webb off course. To prevent this, the telescope has a flap that
acts as a rudder, said Webb sunshield manager Jim Flynn of Northrup Grumman in
a January 4 news conference.
Cooling down
Webb sees in
infrared light, wavelengths longer than what the human eye can see. But humans
do experience infrared radiation as heat. “We’re essentially looking at the
universe in heat vision,” says astrophysicist Erin Smith of Goddard Space
Flight Center and a project scientist on Webb.
That means
that the parts of the telescope that observe the sky have to be at about 40
kelvins (–233° Celsius), which nearly matches the cold of space. That way, Webb
avoids emitting more heat than the distant sources in the universe that the
telescope will be observing, preventing it from obscuring them from view.
Most of Webb
has been cooling down ever since the telescope’s sunshield unfurled on January 4.
The observatory’s five-layer sunshield blocks and deflects heat and light,
letting the telescope’s mirrors and scientific instruments cool off from their
temperature at launch. The sunshield layer closest to the sun will warm to
about 85° Celsius, but the cold side will be about –233° Celsius, Parrish said
in a January 4 webcast.
“You could
boil water on the front side of us, and on the backside of us, you’re almost
down to absolute zero,” Parrish said.
One of the
instruments, MIRI, the Mid-Infrared Instrument, has extra coolant to bring it
down to 6.7 kelvins (–266° Celsius) to enable it to see even dimmer and cooler
objects than the rest of the telescope. For MIRI, “space isn’t cold enough,”
Smith says.
Aligning the mirrors
Webb finished
unfolding its 6.5-meter-wide golden mirror on January 8, turning the spacecraft
into a true telescope. But it’s not done yet. That mirror, which collects and
focuses light from the distant universe, is made up of 18 hexagonal segments.
And each of those segments has to line up with a precision of about 10 or 20
nanometers so that the whole apparatus mimics a single, wide mirror.
Webb will
train each of its 18 mirror segments on a single bright star called HD 84406,
in the constellation Ursa Major. It’s “just near the bowl of the big dipper.
You can’t quite see it with your naked eye but I’m told you can see it with
binoculars,” Lee Feinberg, Webb optical telescope element manager at Goddard
said at the January 24 news conference.
Starting on January 12, 126 tiny
motors on the back of the 18 segments started moving and reshaping them to make
sure they all match up. Another six motors went to work on the secondary
mirror, which is supported on a boom in front of the primary mirror.
This
alignment process will take until at least April to finish. In part, that’s
because the movements are happening while the mirror is cooling. The changing
temperature changes the shape of the mirrors, so they can’t be put in their
final alignment until after the telescope’s suite of scientific instruments are
fully chilled.
Once the initial
alignment is done, light from distant space will first bounce off the primary
mirror, then the secondary mirror and finally reach the instruments that will
analyze the cosmic signals. But the alignment of the mirror segments is “not
just right now, it’s a continuous process, just to make sure that they’re
always perfectly aligned,” Scarlin Hernandez, a flight systems engineer at the
Space Telescope Science Institute in Baltimore said at a NASA Science Live
event on January 24. The process will continue for the telescope’s lifetime.
Calibrating the science instruments
While the
mirrors are aligning, Webb’s science instruments will turn on. Technically,
this is when Webb will take its first pictures, says astronomer Klaus
Pontoppidan, also of the Space Telescope Science Institute. “But they’re not
going to be pretty,” Pontoppidan says. The telescope will first test its focus
on a single bright star, bringing 18 separate bright dots into one by tilting
the mirrors.
After a few
final adjustments, the telescope will be “performing as we want it to and
presenting beautiful images of the sky to all the instruments,” Friedman says.
“Then they can start doing their work.”
These
instruments include NIRCam, the primary
near-infrared camera that will cover the range of wavelengths from 0.6 to 5
micrometers. NIRCam will be able to image the earliest stars and galaxies as
they were when they formed at least 12 billion years ago, as well as young
stars in the Milky Way. The camera will also be able to see objects in the
Kuiper Belt at the edge of the solar system and is equipped with a coronagraph,
which can block light from a star to reveal details of dimmer exoplanets
orbiting it.
Next up is NIRSpec, the
near-infrared spectrograph, which will cover the same range of light
wavelengths as NIRCam. But instead of collecting light and turning it into an
image, NIRSpec will split the light into a spectrum to figure out an object’s
properties, such as temperature, mass and composition. The spectrograph is
designed to observe 100 objects at the same time.
MIRI, the
mid-infrared instrument, is kept the coldest to observe in the longest
wavelengths, from 5 to 28 micrometers. MIRI has both a camera and a
spectrograph that, like NIRCam and NIRSpec, will still be sensitive to distant
galaxies and newborn stars, but it will also be able to spot planets, comets
and asteroids.
And the fourth
instrument, called the FGS/NIRISS, is a
two-parter. FGS is a camera that will help the telescope point precisely. And
NIRISS, which stands for near-infrared imager and slitless spectrograph, will
be specifically used to detect and characterize exoplanets.
First science targets
It will take
at least another five months after arriving at L2 to finish calibrating all of
those science instruments, Pontoppidan says. When that’s all done, the Webb
science team has a top secret plan for the first full color images to be
released.
“These are
images that are meant to demonstrate to the world that the observatory is
working and ready for science,” Pontoppidan says. “Exactly what will be in that
package, that’s a secret.”
Partly the
secrecy is because there’s still some uncertainty in what the telescope will be
able to look at when the time comes. If setting up the instruments takes longer
than expected, Webb will be in a different part of its orbit and certain parts
of the sky will be out of view for a while. The team doesn’t want to promise
something specific and then be wrong, Pontoppidan says.
But also,
“it’s meant to be a surprise,” he says. “We don’t want to spoil that surprise.”
Webb’s first
science projects, however, are not under wraps. In the first five months of
observations, Webb will begin a series of Early Release Science projects.
These will use every feature of every instrument to look at a broad range of
space targets, including everything from Jupiter to distant galaxies and from
star formation to black holes and exoplanets.
Still, even
the scientists are eager for the pretty pictures.
“I’m just very
excited to get to see those first images, just because they will be
spectacular,” Smith says. “As much as I love the science, it’s also fun to ooh
and ahh.”
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