Astronomy and Planetary Science Thread

WASP-127b: A misaligned planet with a partly cloudy atmosphere and tenuous sodium signature seen by ESPRESSO

The study of exoplanet atmospheres is essential to understand the formation, evolution and composition of exoplanets. The transmission spectroscopy technique is playing a significant role in this domain. In particular, the combination of state-of-the-art spectrographs at low- and high-spectral resolution is key to our understanding of atmospheric structure and composition. Two transits of the close-in sub Saturn-mass planet,WASP-127b, have been observed with ESPRESSO in the frame of the Guaranteed Time Observations Consortium. Transit observations allow us to study simultaneously the system architecture and the exoplanet atmosphere. We found that this planet is orbiting its slowly rotating host star (veq sin(i)=0.53+/-0.07 km/s) on a retrograde misaligned orbit (lambda=-128.41+/-5.60 deg). We detected the sodium line core at the 9-sigma confidence level with an excess absorption of 0.3+/-0.04%, a blueshift of 2.7+/-0.79 km/s and a FWHM of 15.18+/-1.75 km/s. However, we did not detect the presence of other atomic species but set upper-limits of only few scale heights. Finally, we put a 3-sigma upper limit, to the average depth of the 1600 strongest water lines at equilibrium temperature in the visible band, of 38 ppm. This constrains the cloud-deck pressure between 0.3 and 0.5 mbar by combining our data with low-resolution data in the near-infrared and models computed for this planet. To conclude, WASP-127b, with an age of about 10 Gyr, is an unexpected exoplanet by its orbital architecture but also by the small extension of its sodium atmosphere (~7 scale heights). ESPRESSO allows us to take a step forward in the detection of weak signals, thus bringing strong constraints on the presence of clouds in exoplanet atmospheres. The framework proposed in this work can be applied to search for molecular species and study cloud-decks in other exoplanets.

WASP-127b: A misaligned planet with a partly cloudy atmosphere and tenuous sodium signature seen by ESPRESSO

The study of exoplanet atmospheres is essential to understand the formation, evolution and composition of exoplanets. The transmission spectroscopy technique is playing a significant role in this domain. In particular, the combination of state-of-the-art spectrographs at low- and high-spectral...
arxiv.org
 
Better than a lava lamp.

Some hot exoplanets may develop strange sets of four colossal storms

Simulation of a modon on an exoplanet, with storms that rotate in opposite directions at opposite poles Some giant planets may have two enormous pairs of storms that stir up their atmospheres. These colossal couples, called modons, spin in opposite directions and are expected to completely...
www.newscientist.com

(Paywalled)

Preprint here:

Modons on Tidally Synchronised Extrasolar Planets

We investigate modons on tidally synchronised extrasolar planets. Modons are highly dynamic, coherent flow structures composed of a pair of storms with opposite signs of vorticity. They are important because they divert flows on the large-scale; and, powered by the intense irradiation from the...
arxiv.org

This is about hot Jupiters, but it's interesting because if there's an atmosphere, the climate models of tidally-locked planets being 'too hot on the day side, too cold on the night side, thin habitable ring in the twilight zone' are way too simplistic, so there might be some application to studies of hypothetical 'mearths' - earthlike planets around red dwarfs. Models I have seen for mearths generally show complementary polar vortices feeding a stream that whips around to the nightside, delivering warm air and possibly moisture there.
 

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Study Finds Photosynthesis in Venus’ Clouds Could Support Life

New data analysis has found that the sunlight filtering through Venus’ clouds could support Earth-like photosynthesis in the cloud layers and that chemical conditions are potentially amenable to the growth of microorganisms.
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Study Finds Photosynthesis in Venus’ Clouds Could Support Life | PolyCentric

polycentric.cpp.edu

Potential for Phototrophy in Venus' Clouds

Abstract

We show that solar irradiances calculated across Venus' clouds support the potential for Earth-like phototrophy and that treatment of Venus' aerosols containing neutralized sulfuric acid favor a habitable zone. The phototrophic potential of Venus' atmosphere was assessed by calculating irradiances (200–2000 nm, 15° solar zenith angle, local noon) using a radiative transfer model that accounted for absorption and scattering by the major and minor atmospheric constituents. Comparisons to Earth's surface (46 W m−2, 280–400 nm) suggest that Venus' middle and lower clouds receive ∼87% less normalized UV flux (6–7 W m−2) across 200–400 nm, yet similar normalized photon flux densities (∼4400–6200 μmol m−2 s−1) across 350–1200 nm. Further, Venus' signature phototrophic windows and subwindows overlap with the absorption profiles of several photosynthetic pigments, especially bacteriochlorophyll b from intact cells and phycocyanin. Therefore, Venus' light, with limited UV flux in the middle and lower clouds, is likely quite favorable for phototrophy. We additionally present interpretations to refractive index and radio occultation measures for Venus' aerosols that suggest the presence of lower sulfuric abundances and/or neutralized forms of sulfuric acid, such as ammonium bisulfate. Under these considerations, the aerosols in Venus' middle clouds could harbor water activities (≥0.6) and buffered acidities (Hammett acidity factor, H0 -0.1 to -1.5) that lie within the limits of acidic cultivation (≥H0 -0.4) and are tantalizingly close to the limits of oxygenic photosynthesis (≥H0 0.1). Together, these photophysical and chemical considerations support a potential for phototrophy in Venus' clouds.

 
GW Ori: circumtriple rings and planets

ABSTRACT
GW Ori is a hierarchical triple star system with a misaligned circumtriple protoplanetary disc. Recent Atacama Large Millimeter/submillimeter Array observations have identified three dust rings with a prominent gap at 100au
and misalignments between each of the rings. A break in the gas disc may be driven by the torque from either the triple star system or a planet that is massive enough to carve a gap in the disc. Once the disc is broken, the rings nodally precess on different time-scales and become misaligned. We investigate the origins of the dust rings by means of N-body integrations and 3D hydrodynamic simulations. We find that for observationally motivated parameters of protoplanetary discs, the disc does not break due to the torque from the star system. We suggest that the presence of a massive planet (or planets) in the disc separates the inner and outer discs. We conclude that the disc breaking in GW Ori is likely caused by undetected planets – the first planet(s) in a circumtriple orbit.

GW Ori: circumtriple rings and planets

ABSTRACT. GW Ori is a hierarchical triple star system with a misaligned circumtriple protoplanetary disc. Recent Atacama Large Millimeter/submillimeter Arr
academic.oup.com
 
View: https://twitter.com/SpcPlcyOnline/status/1442908742635298818


Hertz [NASA astrophysics division director Paul Hertz] says everyone is "eagerly" awaiting the astrophysics Decadal Survey, but NASA had to move on w/o it. Had to formulate FY2023 budget req already, so it obviously doesn't contain $ for anything it. Hope it's out in time to guide next call for tech proposals in mid-Dec.

Q-if Decadal recommends new flagship can it launch in 2030s?
Hertz-priority is launching the 2 flagships we already have, JWST and Roman, & demonstrate to stakeholders we can do these missions. Then will decide right time to start a new one. Don't know what'll be recommended.
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Energy burst from most distant known galaxy might have been a satellite orbiting Earth

Gamma rays are one of the most energetic forms of light, and gamma ray bursts release almost unimaginable quantities of them. First discovered during the cold war – by military satellites searching for the signs of nuclear tests in the upper atmosphere – gamma ray bursts are now thought to be caused by massive stars undergoing huge explosions when they run out of fuel. These events are rare, but so energetic they can be seen in galaxies many billions of light years away.

Recently, astronomers thought they had seen evidence for one of these explosions from the most distant galaxy every seen. But a recently published paper casts doubt on these claims, suggesting it might have been caused by a more mundane source much closer to home.
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Around the time that the original team were studying the sky, a Russian proton rocket reached low Earth orbit and released its upper stages (dubbed Breeze-M), which then became space junk, orbiting the Earth. By looking at the orbit of the space debris and matching with the observations taken in the original study, the new team found the flash could be simply explained by the upper stage falling past the part of the sky the telescope was observing.
Click to expand...

Energy burst from most distant known galaxy might have been a satellite orbiting Earth

Did we observe the most distant gamma ray burst yet seen, or was it something closer to home?
theconversation.com

Related paper:

GN-z11-flash from a man-made satellite not a gamma-ray burst at redshift 11

GN-z11-flash from a man-made satellite not a gamma-ray burst at redshift 11 - Nature Astronomy

www.nature.com
 
Astronomers discover 'extraordinary' unknown radio signal from heart of Milky Way

Across the vast desert plains of Western Australia, on the lands of the Wajarri Yamatji people, lies one of the most capable radio telescope arrays in the world. Containing 36 dish antennas, the Australian Square Kilometre Array Pathfinder, ASKAP, is an eye to the universe. The three dozen antennas watch for radio waves that crash over the Earth.

Over the last two years the antennas have, on occasion, been pointed toward the heart of the Milky Way, our home galaxy. And, on occasion, they've detected a highly unusual radio signal -- one that does not seem to fit with any object we currently know is lurking in the cosmos.

The detection of the signal appears in the Astrophysical Journal on Oct. 12. It was first published as a preprint on arXiv in September.

The name of the strange signal is a mouthful: ASKAP J173608.2-321635. We're going to call it the Ghost. Between April 2019 and August 2020, the Ghost was spotted 13 times but without any consistent timing.
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'Extraordinary' unknown radio signal from heart of Milky Way puzzles astronomers

What buzzed Earth from the center of the galaxy? Scientists are trying to work that out.
www.cnet.com

Here’s the related paper:

 
The population of M dwarfs observed at low radio frequencies

Abstract
Coherent low-frequency (≲200 MHz) radio emission from stars encodes the conditions of the outer corona, mass-ejection events and space weather1,2,3,4,5. Previous low-frequency searches for radio-emitting stellar systems have lacked the sensitivity to detect the general population, instead largely focusing on targeted studies of anomalously active stars5,6,7,8,9. Here we present 19 detections of coherent radio emission associated with known M dwarfs from a blind flux-limited low-frequency survey. Our detections show that coherent radio emission is ubiquitous across the M dwarf main sequence, and that the radio luminosity is independent of known coronal and chromospheric activity indicators. While plasma emission can generate the low-frequency emission from the most chromospherically active stars of our sample1,10, the origin of the radio emission from the most quiescent sources is yet to be ascertained. Large-scale analogues of the magnetospheric processes seen in gas giant planets3,11,12 probably drive the radio emission associated with these quiescent stars. The slowest-rotating stars of this sample are candidate systems to search for star–planet interaction signatures.

The population of M dwarfs observed at low radio frequencies - Nature Astronomy

The authors present 19 detections of coherent low-frequency radio emission from M dwarfs using the Low Frequency Array. The sample includes both chromospherically active and quiescent stars, but radio luminosities are independent of coronal and chromospheric activity indicators.
www.nature.com

Source: https://www.popsci.com/space/radio-signals-exoplanets/
 
Probably stretching the terms of this thread but I thought this was interesting.

In A.D. 993, a storm on the sun released an enormous pulse of radiation that was absorbed and stored by trees all over the Earth. Now, that solar event has proved a critical tool in pinpointing an exact year the Vikings were present in the Americas.
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There was one more thing that stood out: Three of the wood samples were from trees alive during the solar event of 993, when the cosmic storm released a pulse of radiation so powerful that it was recorded in the rings of the world’s trees. Referred to by researchers as a “cosmogenic radiocarbon event,” the phenomenon has only happened twice in the last 2,000 years.
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Ancient solar storm pinpoints Viking settlement in Americas exactly 1,000 years ago

An analysis of wood from L’Anse aux Meadows zeroes in on a cosmic event to reveal that the European seafarers were felling trees in Newfoundland in A.D. 1021.
www.nationalgeographic.com
 
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A Stable H2O Atmosphere on Europa’s Trailing Hemisphere From HST Images

Abstract​

Previous studies of the global intensities of the oxygen emissions at 1,356 Å and 1,304 Å revealed molecular oxygen (O2) in Europa's atmosphere. Here we investigate the relative changes of the two oxygen emissions when Europa emerges from eclipse as well as the radial profiles of the relative emissions across the sunlit disk in Hubble Space Telescope observations taken in 1999, 2012, 2014, and 2015 while the moon was at various orbital positions. The eclipse observation constrains the atomic oxygen (O) column density to
urn:x-wiley:00948276:media:grl63016:grl63016-math-0001
urn:x-wiley:00948276:media:grl63016:grl63016-math-0002
or lower. We then find that the OI1356-Å/OI1304-Å ratio systematically decreases towards the disk center on the trailing hemisphere. The observed emission ratio pattern and the persistence of it from 1999 to 2015 imply a stable H2O abundance in the central sunlit trailing hemisphere with an H2O/O2 ratio of 12–22. On the leading hemisphere, the emissions are consistent with a pure O2 atmosphere everywhere across the moon disk.

Plain Language Summary​

Observations by the Hubble Space Telescope in far-ultraviolet light of Jupiter's icy moons were used in the past to detect their oxygen atmospheres. Results of a new analysis of images and spectra of the moon Ganymede have recently shown that the same observations also contain information that water vapor is abundant in the atmosphere in addition to oxygen. We use the same analysis here for Europa and find a water vapor atmosphere as well, but only above the orbital trailing hemisphere of the moon.

Error - Cookies Turned Off

agupubs.onlinelibrary.wiley.com
 
Unfortunately the link in this article to the related paper is broken.

Signs of an extreme planet found in another galaxy

In a study published today in the journal Nature Astronomy, researchers led by astrophysicist Rosanne Di Stefano argue that M51-ULS-1, the x-ray binary system within the Whirlpool Galaxy, may host a Saturn-size planet that orbits as far from the binary as Uranus does from our sun.

If this planet really exists, M51-ULS-1 would mark the first pinpointed star system in another galaxy that has an “extroplanet,” or a planet found outside of our home galaxy, the Milky Way.
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Signs of an extreme planet found in another galaxy

An odd x-ray signal hints that a Saturn-size world could be the first known planet lurking in the Whirlpool Galaxy 28 million light-years away.
www.nationalgeographic.com
 
Not so fast on those claims of having discovered the first exoplanet outside the Milky Way.

"Either this is a completely unexpected exoplanet discovered almost immediately in a small amount of data or it's something quite common or garden variety," says Benjamin Pope, an astrophysicist studying exoplanets at the University of Queensland in Australia.
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Pope is less convinced. "Personally, I wouldn't bet that this is a planet," he says. "In my view this is probably a stellar companion or something exotic happening in the disk."
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Pope notes that if we found analogous systems in the Milky Way, we'd be able to follow up with optical telescopes and get a better understanding of what might be happening at these types of systems.

We know there must be planets outside of the Milky Way and so, eventually, humans will discover them. For Galloway, the study is exciting not because of what caused the X-ray binary to dip in brightness, but what happens next.

"The really exciting thing is there might be additional events in other data, so now we have a motivation where we can go and look for them," he says.
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Have astronomers found the first planet outside of our galaxy? It's complicated

A new study claims to have detected evidence of a planet outside of the Milky Way. Not everyone is convinced.
www.cnet.com
 
While analyzing some of the world's oldest coloured gemstones, researchers from the University of Waterloo discovered carbon residue that was once ancient life, encased in a 2.5 billion-year-old ruby.
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Some of the world’s oldest rubies linked to early life

While analyzing some of the world's oldest colored gemstones, researchers discovered carbon residue that was once ancient life, encased in a 2.5 billion-year-old ruby.
www.sciencedaily.com
 

Juno Reveals Deep 3D Structure of Jupiter's Massive Storms - Slashdot

Nasa's Juno mission, the solar-powered robotic explorer of Jupiter, has completed its five-year prime mission to reveal the inner workings of the Solar System's biggest planet. The most recent findings from these measurements have now been published in a series of papers, revealing the...
science.slashdot.org
 
Science goals and new mission concepts for future exploration of Titan's atmosphere geology and habitability: Titan POlar Scout/orbitEr and In situ lake lander and DrONe explorer (POSEIDON)

In response to ESA Voyage 2050 announcement of opportunity, we propose an ambitious L-class mission to explore one of the most exciting bodies in the Solar System, Saturn largest moon Titan. Titan, a "world with two oceans", is an organic-rich body with interior-surface-atmosphere interactions that are comparable in complexity to the Earth. Titan is also one of the few places in the Solar System with habitability potential. Titan remarkable nature was only partly revealed by the Cassini-Huygens mission and still holds mysteries requiring a complete exploration using a variety of vehicles and instruments. The proposed mission concept POSEIDON (Titan POlar Scout/orbitEr and In situ lake lander DrONe explorer) would perform joint orbital and in situ investigations of Titan. It is designed to build on and exceed the scope and scientific/technological accomplishments of Cassini-Huygens, exploring Titan in ways that were not previously possible, in particular through full close-up and in situ coverage over long periods of time. In the proposed mission architecture, POSEIDON consists of two major elements: a spacecraft with a large set of instruments that would orbit Titan, preferably in a low-eccentricity polar orbit, and a suite of in situ investigation components, i.e. a lake lander, a "heavy" drone (possibly amphibious) and/or a fleet of mini-drones, dedicated to the exploration of the polar regions. The ideal arrival time at Titan would be slightly before the next northern Spring equinox (2039), as equinoxes are the most active periods to monitor still largely unknown atmospheric and surface seasonal changes. The exploration of Titan northern latitudes with an orbiter and in situ element(s) would be highly complementary with the upcoming NASA New Frontiers Dragonfly mission that will provide in situ exploration of Titan equatorial regions in the mid-2030s.
Click to expand...
 
Imagine that, the atmosphere itself condensing, falling as snow - and a couple of centuries hence that snow will boil away into air once more.

Pluto's atmosphere may be starting to condense

Beginning three years after New Horizons' historic flyby, Pluto's atmosphere appeared to be starting to condense and refreeze, according to scientists.
www.spaceflightinsider.com
 
Recent estimates of the characteristics of Planet Nine have suggested that it could be closer than originally assumed. Such a Planet Nine would also be brighter than originally assumed, suggesting the possibility that it has already been observed in wide-field moderate-depth surveys. We search for Planet Nine in the Zwicky Transient Facility public archive and find no candidates. Using known asteroids to calculate the magnitude limit of the survey, we find that we should have detected Planet Nine throughout most of the northern portion of its predicted orbit -- including within the galactic plane -- to a 95% detection efficiency of approximately V=20.5. To aid in understanding detection limits for this and future analyses, we present a full-sky synthetic Planet Nine population drawn from a statistical sampling of predicted Planet Nine orbits. We use this reference population to estimate that this survey rules out 56% of predicted Planet Nine phase space, and we demonstrate how future analyses can use the same synthetic population to continue to constrain the amount of parameter space effectively searched for Planet Nine.
Click to expand...

http://findplanetnine.blogspot.com/2021/10/the-hunt-is-on.html?m=1

Related paper:

https://arxiv.org/abs/2110.13117
 
Related Twitter thread by Mike Brown starting here:

View: https://twitter.com/plutokiller/status/1452842758767403009

And his response to being asked the chances of finding it by 2025:

View: https://twitter.com/plutokiller/status/1452845827127271424
 
The First Astronomers

For thousands of years indigenous Australians, the longest living culture on Earth, have been fascinated by the stars. In this episode Kamilaroi man and ANU astrophysics graduate Peter Swanton shines a light on the great depth of knowledge indigenous Australians associate with various constellations: from the multi-layered story about the Southern Cross to the unique study of the Dark Emu to how Torres Strait islanders used the phases of the Moon for weather predictions and seasons.

The First Astronomers | The Ancients

For thousands of years indigenous Australians, the longest living culture on Earth, have been fascinated by the stars. In this episode, Gamilaraay man and ANU astrophysics graduate Peter Swanton shines a light on Australian Indigenous Astronomy and the...
play.acast.com
 
Solar Foci ‘scopes should be a priority. The first more or less aimed at the galactic core. Target rich…allows us to learn how to aim. If we zoom in on Sagittarius A*, then an improved Solar Foci ‘scope #2 looks at Andromeda. The third dedicated to Gliese 710. The fourth Proxima. Save fast moving Barnard’s Star for last.
 
GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run

The third Gravitational-wave Transient Catalog (GWTC-3) describes signals detected with Advanced LIGO and Advanced Virgo up to the end of their third observing run. Updating the previous GWTC-2.1, we present candidate gravitational waves from compact binary coalescences during the second half of the third observing run (O3b) between 1 November 2019, 15:00 UTC and 27 March 2020, 17:00 UTC. There are 35 compact binary coalescence candidates identified by at least one of our search algorithms with a probability of astrophysical origin pastro>0.5. Of these, 18 were previously reported as low-latency public alerts, and 17 are reported here for the first time. Based upon estimates for the component masses, our O3b candidates with pastro>0.5 are consistent with gravitational-wave signals from binary black holes or neutron star-black hole binaries, and we identify none from binary neutron stars. However, from the gravitational-wave data alone, we are not able to measure matter effects that distinguish whether the binary components are neutron stars or black holes. The range of inferred component masses is similar to that found with previous catalogs, but the O3b candidates include the first confident observations of neutron star-black hole binaries. Including the 35 candidates from O3b in addition to those from GWTC-2.1, GWTC-3 contains 90 candidates found by our analysis with pastro>0.5 across the first three observing runs. These observations of compact binary coalescences present an unprecedented view of the properties of black holes and neutron stars.

GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo During the Second Part of the Third Observing Run

The third Gravitational-Wave Transient Catalog (GWTC-3) describes signals detected with Advanced LIGO and Advanced Virgo up to the end of their third observing run. Updating the previous GWTC-2.1, we present candidate gravitational waves from compact binary coalescences during the second half of...
arxiv.org

Source: https://phys.org/news/2021-11-scientists-tsunami-gravitational.html
 
NASA, USGS Release First Landsat 9 Images

Landsat 9, a joint mission between NASA and the U.S. Geological Survey (USGS) that launched Sept. 27, 2021, has collected its first light images of Earth.

The images, all acquired Oct. 31, are available online. They provide a preview of how the mission will help people manage vital natural resources and understand the impacts of climate change, adding to Landsat’s unparalleled data record that spans nearly 50 years of space-based Earth observation.

“Landsat 9’s first images capture critical observations about our changing planet and will advance this joint mission of NASA and the U.S. Geological Survey that provides critical data about Earth's landscapes and coastlines seen from space,” said NASA Administrator Bill Nelson. “This program has the proven power to not only improve lives but also save lives. NASA will continue to work with USGS to strengthen and improve accessibility to Landsat data so decision makers in America – and around the world – better understand the devastation of the climate crisis, manage agricultural practices, preserve precious resources and respond more effectively to natural disasters.”

These first light images shows Detroit, Michigan, with neighboring Lake St. Clair, the intersection of cities and beaches along a changing Florida coastline and images from Navajo Country in Arizona that will add to the wealth of data helping us monitor crop health and manage irrigation water. The new images also provided data about the changing landscapes of the Himalayas in High Mountain Asia and the coastal islands and shorelines of Northern Australia.

Landsat 9 is similar in design to its predecessor, Landsat 8, which was launched in 2013 and remains in orbit, but features several improvements. The new satellite transmits data with higher radiometric resolution back down to Earth, allowing it to detect more subtle differences, especially over darker areas like water or dense forests. For example, Landsat 9 can differentiate more than 16,000 shades of a given wavelength color; Landsat 7, the satellite being replaced, detects only 256 shades. This increased sensitivity will allow Landsat users to see much more subtle changes than ever before.

“First light is a big milestone for Landsat users – it’s the first chance to really see the kind of quality that Landsat 9 provides. And they look fantastic,” said Jeff Masek NASA’s Landsat 9 project scientist at Goddard Space Flight Center. “When we have Landsat 9 operating in coordination with Landsat 8, it’s going to be this wealth of data, allowing us to monitor changes to our home planet every eight days.”

Landsat 9 carries two instruments that capture imagery: the Operational Land Imager 2 (OLI-2), which detects visible, near-infrared and shortwave-infrared light in nine wavelengths, and the Thermal Infrared Sensor 2 (TIRS-2), which detects thermal radiation in two wavelengths to measure Earth’s surface temperatures and its changes.

These instruments will provide Landsat 9 users with essential information about crop health, irrigation use, water quality, wildfire severity, deforestation, glacial retreat, urban expansion, and more.

“The data and images from Landsat 9 are expanding our capability to see how Earth has changed over decades”, said Karen St. Germain, Earth Science Division director at NASA Headquarters in Washington. “In a changing climate, continuous and free access to Landsat data, and the other data in NASA’s Earth observing fleet, helps data users, including city planners, farmers and scientists, plan for the future.”

NASA’s Landsat 9 team is conducting a 100-day check-out period that involves testing the satellite’s systems and subsystems and calibrating its instruments in preparation for handing the mission over to USGS in January. USGS will operate Landsat 9 along with Landsat 8, and together the two satellites will collect approximately 1,500 images of Earth’s surface every day, covering the globe every eight days.

“The incredible first pictures from the Landsat 9 satellite are a glimpse into the data that will help us make science-based decisions on key issues including water use, wildfire impacts, coral reef degradation, glacier and ice-shelf retreat and tropical deforestation,” said USGS Acting Director Dr. David Applegate. “This historic moment is the culmination of our long partnership with NASA on Landsat 9’s development, launch and initial operations, which will better support environmental sustainability, climate change resiliency and economic growth – all while expanding an unparalleled record of Earth's changing landscapes.” 

Landsat 9 data will be available to the public, for free, from USGS’s website once the satellite begins normal operations.

NASA manages the Landsat 9 mission development. Teams from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, also built and tested the TIRS-2 instrument. NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida, managed the mission’s launch. The USGS Earth Resources Observation and Science (EROS) Center will operate the mission and manage the ground system, including maintaining the Landsat archive. Ball Aerospace in Boulder, Colorado, built and tested the OLI-2 instrument. United Launch Alliance is the rocket provider for Landsat 9’s launch. Northrop Grumman in Gilbert, Arizona, built the Landsat 9 spacecraft, integrated it with instruments, and tested it.

For more information on Landsat 9 and the Landsat program, visit:



 

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Phys.org had an article on how dark matter can make more of itself by absorbing normal matter. I wonder if those two linear earthquakes SMU picket up were strangelets out of the Hyades, where something truly Lovecraftian does seem to be happening IRL.
 
A GeV-TeV particle component and the barrier of cosmic-ray sea in the Central Molecular Zone

Abstract
Cosmic rays are important probe of a number of fundamental physical problems such as the acceleration of high and very high energy particles in extreme astrophysical environments. The Galactic center is widely anticipated to be an important cosmic-ray source and the observations of some Imaging Atmospheric Cherenkov Telescopes did successfully reveal a component of TeV-PeV cosmic rays in the vicinity of the Galactic center. Here we report the identification of GeV-TeV cosmic rays in the central molecular zone with the γ-ray observations of the Fermi Large Area Telescope, whose spectrum and spatial gradient are consistent with that measured by the Imaging Atmospheric Cherenkov Telescopes but the corresponding cosmic-ray energy density is substantially lower than the so-called cosmic-ray sea component, suggesting the presence of a high energy particle accelerator at the Galactic center and the existence of a barrier that can effectively suppress the penetration of the particles from the cosmic-ray sea to the central molecular zone.

A GeV-TeV particle component and the barrier of cosmic-ray sea in the Central Molecular Zone - Nature Communications

Galactic center is one of the most important cosmic-ray sources. Here, the authors show GeV-TeV cosmic ray density in the central molecular zone is lower than the cosmic ray sea component, suggesting presence of high energy particle accelerator at the galactic center and existence of barrier.
www.nature.com

Source: https://phys.org/news/2021-11-fermi-large-area-telescope-particle.html
 
Fun paper out today on the search for Planet Nine using old IRAS data. Nothing too compelling, but there is one candidate that Rowan-Robinson mentions, before mostly dismissing it as unlikely-to-be real. Still, if is fun to ponder: what if it IS real?
Click to expand...
View: https://mobile.twitter.com/plutokiller/status/1458038427090178052
 
Here’s the paper:

A search for Planet 9 in the IRAS data

I have carried out a search for Planet 9 in the IRAS data. At the distance range proposed for Planet 9, the signature would be a 60 micron unidentified IRAS point source with an associated nearby source from the IRAS Reject File of sources which received only a single hours-confirmed (HCON) detection. The confirmed source should be detected on the first two HCON passes, but not on the third, while the single HCON should be detected only on the third HCON. I have examined the unidentified sources in three IRAS 60micron catalogues: some can be identified with 2MASS galaxies, Galactic sources or as cirrus. The remaining unidentified sources have been examined with the IRSA Scanpi tool to check for the signature missing HCONs, and for association with IRAS Reject File single HCONs. No matches of interest survive.
For a lower mass planet (< 5 earth masses) in the distance range 200-400 AU, we expect a pair or triplet of single HCONs with separations 2-35 arcmin. Several hundred candidate associations are found and have been examined with Scanpi. A single candidate for Planet 9 survives which satisfies the requirements for detected and non-detected HCON passes. A fitted orbit suggest a distance of 225+-15 AU and a mass of 3-5 earth masses. Dynamical simulations are needed to explore whether the candidate is consistent with existing planet ephemerides. If so, a search in an annulus of radius 2.5-4 deg centred on the 1983 position at visible and near infrared wavelengths would be worthwhile.

A search for Planet 9 in the IRAS data

I have carried out a search for Planet 9 in the IRAS data. At the distance range proposed for Planet 9, the signature would be a 60 micron unidentified IRAS point source with an associated nearby source from the IRAS Reject File of sources which received only a single hours-confirmed (HCON)...
arxiv.org
 


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