Zitat Jasmine 🌌🔭 @astro_jaz WE ARE GETTING JWST OBSERVATIONS OF OUR SOLAR SYSTEM LATER THIS WEEK 😭😭😭 MY HEART CANT HANDLE THIS. 12:09 AM · Jul 13, 2022·Twitter for iPhone
AND OBSERVATIONS OF EVERY PLANET IN THE TRAPPIST SYSTEM OH MY GOD.
Zitat von ZRDie Galaxie, deren Spektrum jetzt das des am weitesten entfernte Objekt darstellt, bei dem eine solche Analyse vorliegt, liegt in einer Entfernung von 13,1 Milliarden Lichtjahren, wir sehen ihren Zustand also zu einem Zeitpunkt, als das Universum selbst erst ein Alter von einem halben bis knapp einer ganzen Milliarde von Jahren erreicht hatte. Solchen Analysen werden in Zukunft sehr hilfreich sein, die Frühzeit des Universums genauer zu bestimmen: die ersten Generationen von Sternen haben sich aus den Elementen gebildet, die beim Urknall, beim Big Bang, entstanden sind: Wasserstoff, schwerer Wasserstoff und Helium. Sämtliche Atome aller chemischen Elemente, deren Atomgewicht höher liegt, sind als Asche, als Ergebnis von Fusionsprozessen im Zentrum von Sternen entstanden. ... Über die Geschwindigkeit und den Zuwachs dieser „Metalle“ (wie die Astromomen solche Elemente nennen, sehr zum Leidwesen ihrer Kollegen aus dem Fachbereich Chemie) können spätere Meßreihen Aufschluß geben.
Zitat Molly Peeples @astronomolly At @stsci @alh_ast is presenting spectra of the #jwst deep field. SPECTRUM of a=8.5 galaxy! With super easy to measure metallicity indicators! 4:41 PM · Jul 12, 2022·Twitter for iPhone
MissKittyFantastico @grusthegorilla Replying to @astronomolly @stsci and @alh_ast Ahhhhhh was wondering what the redshift was. That is WILD. Spent part of my thesis looking for z=7.7 galaxies. Holy crap. 4:52 PM · Jul 12, 2022·Twitter for iPhone
Jetzt online: JWST, Carina-Nebel. Bild in voller Auflösung. 100 Megapixel. Draufklicken, Geduld mitbringen (es braucht ein bißchen, bis sich das vollständig aufgebaut hat). Und dann mit der linken Maustaste anklicken, um auf volle Vergrößerung zu schalten.
Zitat von ZREins davon, im linken oberen Quadranten gelegen, wurde zur Ermittlung des Spektrums ausgewählt. Die Galaxie, deren Spektrum jetzt das des am weitesten entfernte Objekt darstellt, bei dem eine solche Analyse vorliegt, liegt in einer Entfernung von 13,1 Milliarden Lichtjahren, wir sehen ihren Zustand also zu einem Zeitpunkt, als das Universum selbst erst ein Alter von einem halben bis knapp einer ganzen Milliarde von Jahren erreicht hatte.
Zitat JWST has found the oldest galaxy we have ever seen in the universe Discoveries from the James Webb Space Telescope are pouring in, with an analysis of the latest data revealing a galaxy that dates back to just 300 million years after the big bang – the oldest we have ever seen
SPACE 20 July 2022
Just weeks into its mission, the James Webb Space Telescope (JWST) has broken the record for the oldest galaxy ever observed by nearly 100 million years.
Seeing some of the first galaxies to form after the big bang 13.8 billion years ago is one of the key goals of the JWST. When these emerged is currently unknown: the previous oldest identified galaxy, found by the Hubble Space Telescope, is called GN-z11 and dates back to 400 million years after the birth of the universe.
Zitat Two Weeks In, the Webb Space Telescope Is Reshaping Astronomy
One of JWST’s much-touted abilities is the power to look back in time to the early universe and see some of the first galaxies and stars. Already, the telescope — which launched on Christmas Day 2021 and now sits 1.5 million kilometers from Earth — has spotted the most distant, earliest galaxy known.
wo teams found the galaxy when they separately analyzed JWST observations for the GLASS survey, one of more than 200 science programs scheduled for the telescope’s first year in space. Both teams, one led by Rohan Naidu at the Harvard-Smithsonian Center for Astrophysics in Massachusetts and the other by Marco Castellano at the Astronomical Observatory of Rome, identified two especially remote galaxies in the data: one so far away that JWST detects the light it emitted 400 million years after the Big Bang (a tie with the oldest galaxy ever seen by the Hubble Space Telescope), and the other, dubbed GLASS-z13, seen as it appeared 300 million years after the Big Bang. “It would be the most distant galaxy ever found,” said Castellano.
Both galaxies look extremely small, perhaps 100 times smaller than the Milky Way, yet they show surprising rates of star formation and already contain 1 billion times the mass of our sun — more than expected for galaxies this young. One of the young galaxies even shows evidence of a disklike structure. More studies will be done to break apart their light to glean their characteristics.
Another early-universe program has also turned up “incredibly distant galaxies,” said Rebecca Larson, an astronomer at the University of Texas, Austin and a member of the Cosmic Evolution Early Release Science (CEERS) survey. Just weeks into the survey, the team has bagged a handful of galaxies from the universe’s first 500 million years, although Larson and her colleagues haven’t released their exact findings yet. “It’s better than I imagined and it’s only the beginning,” she said.
For scientists seeking to understand the structure of galaxies and how stars form within them, JWST has already provided impactful data.
One observing program, led by Janice Lee at the National Science Foundation’s NOIRLab in Arizona, looks for young sites of star formation in galaxies. On behalf of Lee’s team, JWST observed a galaxy 24 million light-years away called NGC 7496, whose young star-forming regions have until now been shrouded in darkness; Hubble’s instruments were unable to penetrate the thick dust and gas that surrounds these regions. JWST, though, can see infrared light that bounces off the dust, allowing the telescope to probe close to the moments when the stars switched on and nuclear fusion ignited in their cores. “The dust is actually lighting up,” said Lee.
What’s most remarkable, she said, is that NGC 7496 is a normal galaxy, “not a poster-child galaxy.” Yet under the watchful eye of JWST, it suddenly comes to life and reveals channels where stars are forming. “It’s just phenomenal,” she said.
Smaller targets are in JWST’s crosshairs, too, including the planets of our own solar system. Jupiter appeared in magnificent fashion as part of the first batch of images, captured in an exposure lasting just 75 seconds.
Astronomers know that Jupiter’s upper atmosphere is hundreds of degrees hotter than the lower atmosphere, but they aren’t sure why. By detecting infrared light, JWST could see the heated upper atmosphere shining; it appears as a red ring around the planet. “We have this layer a few hundred kilometers above the cloud decks, and it’s glowing because it’s hot,” said Henrik Melin, a planetary scientist at the University of Leicester. “We’ve never seen it like this before on a global scale. That’s an extraordinary thing to see.”
Hiding in JWST’s image of Jupiter is the volcanic moon Io interacting with Jupiter’s aurora — creating a small bump in the aurora low in the planet’s sky. The image reveals “material coming from Io streaming down the magnetic field lines,” said Melin. The effect has been seen before, but it was easily picked out by JWST with barely a glance at the planet.
JWST is probing planets in other star systems too. Already, the telescope has taken a peek at the famous TRAPPIST-1 system, a red dwarf star with seven Earth-size worlds (some potentially habitable), though the data is still being analyzed. Early observations have been released of a less hospitable planet, a “hot Jupiter” called WASP-96 b, in a tight 3.4-day orbit around its star.
JWST found water vapor in the planet’s atmosphere, confirming evidence of water reported days earlier by Chima McGruder of the Harvard-Smithsonian Center and colleagues, who used a ground-based telescope. But JWST can go further; by observing WASP-96 b’s ratio of carbon to oxygen, it may be able to solve a confounding mystery about hot Jupiters: how they attain such close orbits around their stars. More oxygen would suggest that the gas giant initially formed far from the star where water could condense, while a higher carbon ratio would suggest that it’s always been close in.
Zitat von Ulrich Elkmann im Beitrag #5Die Galaxie, deren Spektrum jetzt das des am weitesten entfernte Objekt darstellt, bei dem eine solche Analyse vorliegt
Tempi passati.
Zitat Jonathan Amos@BBCAmos It seems @NASAWebb can’t help itself. A candidate galaxy with a redshift of 14 in the ongoing @ceers_jwst survey. Corresponds to an age for the Universe of about 280 million years after the BB. It’s been dubbed Maisie’s Galaxy. 7:57 AM · Jul 26, 2022·Twitter for iPhone
Zitat von Draft version July 25, 2022A Long Time Ago in a Galaxy Far, Far Away: A Candidate z ∼ 14 Galaxy in Early JWST CEERS Imaging
ABSTRACT 27 We report the discovery of a candidate galaxy with a photo-z of z ∼ 14 in the first epoch of the 28 JWST Cosmic Evolution Early Release Science (CEERS) Survey. Following conservative selection criteria we identify a robust source at zphot = 14.3+0.4 −1.1 29 (1σ uncertainty) with mF 277W = 27.8, and 30 >5σ detections in five filters. This object (Maisie’s Galaxy) exhibits F150W−F200W>2.5 mag with 31 a blue continuum slope, resulting in 99.99% (87%) of the photo-z PDF favoring z > 10 (13). All data 32 quality images show no artifacts at the candidate’s position, and independent analyses consistently 33 find a strong preference for z > 13. The source may be marginally detected in HST F160W, which if 34 included would widen the lower-redshift bound to z ∼12.5, and would require very strong Lyα emission 35 (& 300˚A rest-EW) indicating an early ionized bubble. Its colors are inconsistent with Galactic stars, 36 and it is resolved (rh =330+/−30 pc). Maisie’s Galaxy appears modestly massive (log M∗/M ∼8.5) and highly star-forming (log sSFR∼−7.9 yr−1 37 ), with a blue rest-UV color (β ∼ −2.3) indicating 38 little dust though not extremely low metallicities. While the presence of this source is in tension with 39 most predictions, it agrees with empirical extrapolations assuming a smoothly declining SFR density. 40 Should followup spectroscopy validate this redshift, our Universe was already aglow with galaxies less 41 than 300 Myr after the Big Bang.
Es gibt einen ersten Kandidaten für die beliebte Kategorie "das wird die Astronomie revolutionieren."
Zitat James Bullock @jbprime Massive z~10 galaxy candidates from JWST violate integral constraint of available baryons in LCDM. Either stellar mass (or something in data) is wrong or LCDM is wrong. Nice short, clear paper by @MBKplus https://arxiv.org/abs/2208.01611 2:18 PM · Aug 3, 2022·Twitter for iPhone
LCDM steht für Lambda-CDM; "CDM" für "Cold Dark Matter," dem vermuteten 96%igen Anteil "dunkler Materie" (die sich nur durch gravitationelle Wechselwirkung bemerkbar macht; wer nachweisen kann, um WAS es sich handelt, bekommt einen Nobelpreis geschenkt) an der Gesamtmasse des Universums.
Zitat [Submitted on 2 Aug 2022] Stress Testing ΛCDM with High-redshift Galaxy Candidates Michael Boylan-Kolchin (The University of Texas at Austin)
"Early data from JWST have revealed a bevy of high-redshift galaxy candidates with unexpectedly high stellar masses. I examine these candidates in the context of the most massive galaxies expected in ΛCDM-like models, wherein the stellar mass of a galaxy is limited by the available baryonic reservoir of its host dark matter halo. For a given cosmology, the abundance of dark matter halos as function of mass and redshift sets an absolute upper limit on the number density n(>M⋆,z) and stellar mass density ρ⋆(>M⋆,z) of galaxies above a stellar mass limit of M⋆ at any epoch z. The reported masses of the most massive galaxy candidates at z∼10 in JWST observations are in tension with these limits, indicating an issue with well-developed techniques for photometric selection of galaxies, galaxy stellar mass or effective survey volume estimates, or the ΛCDM model. That the strongest tension appears at z∼10, and not (yet?) at the highest redshifts probed by JWST galaxy candidates (z∼16−20), is promising for tests of the ΛCDM model using forthcoming wider-area JWST surveys."
Zitat Webb directly images its 1st exoplanet September 1, 2022
This article was originally published by NASA on September 1, 2022.
For the first time, astronomers have used NASA’s James Webb Space Telescope to take a direct image of a planet outside our solar system. The exoplanet is a gas giant, meaning it has no rocky surface and could not be habitable.
The image, as seen through four different light filters, shows how Webb’s infrared gaze can capture worlds beyond our solar system.
Sasha Hinkley, associate professor of physics and astronomy at the University of Exeter in the United Kingdom, led these observations with a large international collaboration. Hinkley said:
This is a transformative moment, not only for Webb but also for astronomy generally.
Webb images exoplanet HIP 65426 b
The exoplanet in Webb’s image, called HIP 65426 b, is about six to 12 times the mass of Jupiter. These observations could help narrow that down even further. It is young as planets go – about 15 to 20 million years old – compared to our 4.5-billion-year-old Earth.
Astronomers discovered the planet in 2017 using the SPHERE instrument on the European Southern Observatory’s Very Large Telescope in Chile. They took images of it using short infrared wavelengths of light. Webb’s view, at longer infrared wavelengths, reveals new details that ground-based telescopes would not be able to detect because of the intrinsic infrared glow of Earth’s atmosphere.
Researchers have been analyzing the data from these observations and are preparing a paper they will submit to journals for peer review. But Webb’s first capture of an exoplanet already hints at future possibilities for studying distant worlds.
NIRCam and MIRI
Since HIP 65426 b is about 100 times farther from its host star than Earth is from the sun, it is sufficiently distant from the star so Webb can easily separate the planet from the star in the image.
Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) are both equipped with coronagraphs. Coronagraphs are sets of tiny masks that block out starlight, which enable Webb to take direct images of exoplanets like this one. NASA’s Nancy Grace Roman Space Telescope, slated to launch later this decade, will demonstrate an even more advanced coronagraph.
Taking direct images of exoplanets is challenging because stars are so much brighter than planets. The HIP 65426 b planet is more than 10,000 times fainter than its host star in the near-infrared. And it’s a few thousand times fainter in the mid-infrared.
In each filter image, the planet appears as a slightly differently shaped blob of light. That is because of the particulars of Webb’s optical system and how it translates light through the different optics.
Zitat von September 19, 2022Mars Is Mighty in First Webb Observations of Red Planet
NASA’s James Webb Space Telescope captured its first images and spectra of Mars Sept. 5. The telescope, an international collaboration with ESA (European Space Agency) and CSA (Canadian Space Agency), provides a unique perspective with its infrared sensitivity on our neighboring planet, complementing data being collected by orbiters, rovers, and other telescopes.
Webb’s unique observation post nearly a million miles away at the Sun-Earth Lagrange point 2 (L2) provides a view of Mars’ observable disk (the portion of the sunlit side that is facing the telescope). As a result, Webb can capture images and spectra with the spectral resolution needed to study short-term phenomena like dust storms, weather patterns, seasonal changes, and, in a single observation, processes that occur at different times (daytime, sunset, and nighttime) of a Martian day.
Because it is so close, the Red Planet is one of the brightest objects in the night sky in terms of both visible light (which human eyes can see) and the infrared light that Webb is designed to detect. This poses special challenges to the observatory, which was built to detect the extremely faint light of the most distant galaxies in the universe. Webb’s instruments are so sensitive that without special observing techniques, the bright infrared light from Mars is blinding, causing a phenomenon known as “detector saturation.” Astronomers adjusted for Mars’ extreme brightness by using very short exposures, measuring only some of the light that hit the detectors, and applying special data analysis techniques.
Webb’s first images of Mars, captured by the Near-Infrared Camera (NIRCam), show a region of the planet’s eastern hemisphere at two different wavelengths, or colors of infrared light. This image shows a surface reference map from NASA and the Mars Orbiter Laser Altimeter (MOLA) on the left, with the two Webb NIRCam instrument field of views overlaid. The near-infrared images from Webb are on shown on the right.
Zitat A glitch has been detected in one of Webb's seventeen observation modes.
It's unclear at this time how severe the problem is.
The specific mode, known as the Medium-Resolution Spectroscopy (MRS) had experienced an issue characterized as 'increased friction'
Here is the Operations Update from NASA:
The James Webb Space Telescope’s Mid-Infrared Instrument (MIRI) has four observing modes. On Aug. 24, a mechanism that supports one of these modes, known as medium-resolution spectroscopy (MRS), exhibited what appears to be increased friction during setup for a science observation. This mechanism is a grating wheel that allows scientists to select between short, medium, and longer wavelengths when making observations using the MRS mode. Following preliminary health checks and investigations into the issue, an anomaly review board was convened Sept. 6 to assess the best path forward.
The Webb team has paused in scheduling observations using this particular observing mode while they continue to analyze its behavior and are currently developing strategies to resume MRS observations as soon as possible. The observatory is in good health, and MIRI’s other three observing modes – imaging, low-resolution spectroscopy, and coronagraphy – are operating normally and remain available for science observations. Cresit Thaddeus Cesari, NASA.
Zitat Dr Becky Smethurst@drbecky_ Good news! JWST’s observing mode that was suspended (MIRI’s Medium Resolution Spectroscopy mode) is back up and running again! 🥳 @NASAWebb @ESA_Webb 8:47 PM · Nov 8, 2022·Twitter for iPhone
Zitat NASA Webb Telescope @NASAWebb Webb's mirrors were built to withstand micrometeoroids, which are unavoidable in space. In May, a dust-sized hit was larger than tested for. After careful analysis, we've found it to be a rare statistical event. Webb’s optical performance remains twice as good as requirements.
Our team is taking steps to make this rare event even more unlikely. Webb will still see the full sky over the course of its orbit, but observations that face micrometeoroid “zones” will be rescheduled to when Webb can more safely make them from a different location in its orbit.
Thanks to @Arianespace’s precise launch, Webb has fuel for 20+ years of science. With projected mission time significantly extended, our engineers want to optimize Webb for long-term performance. 4:32 PM · Nov 15, 2022·Sprinklr
Zitat News | November 22, 2022 - More Firsts from Webb
NASA's James Webb Space Telescope has just provided the most detailed analysis of an exoplanet atmosphere yet. Researchers were also able to identify sulfur dioxide in the atmosphere, which can only be explained by photocemistry (reactions triggered by starlight). The exoplanet WASP-39 b is also known as Bocaprins, a name bestowed by the International Astronomical Union for a scenic beach in Aruba.
NASA’s James Webb Space Telescope just scored another first: a molecular and chemical profile of a distant world’s skies.
While Webb and other space telescopes, including NASA's Hubble and Spitzer, previously have revealed isolated ingredients of this broiling planet’s atmosphere, the new readings from Webb provide a full menu of atoms, molecules, and even signs of active chemistry and clouds.
The latest data also give a hint of how these clouds might look up close: broken up rather than a single, uniform blanket over the planet.
The telescope’s array of highly sensitive instruments was trained on the atmosphere of WASP-39 b, a “hot Saturn” (a planet about as massive as Saturn but in an orbit tighter than Mercury) orbiting a star some 700 light-years away.
The findings bode well for the capability of Webb’s instruments to conduct the broad range of investigations of all types of exoplanets – planets around other stars – hoped for by the science community. That includes probing the atmospheres of smaller, rocky planets like those in the TRAPPIST-1 system.
“We observed the exoplanet with multiple instruments that, together, provide a broad swath of the infrared spectrum and a panoply of chemical fingerprints inaccessible until [this mission],” said Natalie Batalha, an astronomer at the University of California, Santa Cruz, who contributed to and helped coordinate the new research. “Data like these are a game changer.”
The suite of discoveries is detailed in a set of five new scientific papers, three of which are in press and two of which are under review.
Among the unprecedented revelations is the first detection in an exoplanet atmosphere of sulfur dioxide (SO2), a molecule produced from chemical reactions triggered by high-energy light from the planet’s parent star. On Earth, the protective ozone layer in the upper atmosphere is created in a similar way.
This is the first time we see concrete evidence of photochemistry – chemical reactions initiated by energetic stellar light – on exoplanets,” said Shang-Min Tsai, a researcher at the University of Oxford in the United Kingdom and lead author of the paper explaining the origin of sulfur dioxide in WASP-39 b’s atmosphere. “I see this as a really promising outlook for advancing our understanding of exoplanet atmospheres with [this mission].”
This led to another first: scientists applying computer models of photochemistry to data that requires such physics to be fully explained. The resulting improvements in modeling will help build the technological know-how to interpret potential signs of habitability in the future.
___________________ Verbote sind Freiheit. Meinungen sind Terror. Quoten sind Leistung. Linke Regierung ist Familie. (c) Rot-Grüne Allianz Prophezeiung: 2022, das Jahr in dem in Deutschland der Schleier für alle eingeführt wird. Nennt sich dann "Maske". "Warum halten sie Begriffe wie 'Zigeunersoße' für rassistisch, aber 'Schei** Juden' für harmlos?", Hamed Abdel-Samad
Noch nicht. Da ist nicht von "Photosynthese", sondern nur von "Photochemie" die Rede, die als Ursache der Signatur für Schwefeldioxid im Spektrum nötig ist. Alles andere wäre nach dem Stand der Erkenntnisse auch weit überzogen. Erst wenn sich a-biotische Prozesse mit Sicherheit als Ursache ausschließen lassen, wird sich jemand so weit aus dem Fenster lehnen. Es geht jetzt eher darum, daß man überhaupt in der Lage ist, solche möglichen "Biosignaturen" überhaupt nachzuweisen; auch wenn die Erklärung sich am Ende als prosaischer erweist. Mittlerweile ist es auch um die mgliche Biosignatur in den Wolken der Venus, über die ich vor einiger Zeit geschrieben habe, ziemlich still geworden. Das ist "das Übliche" in diesem Metier: sowohl beim LGM-Signal (für "Little Green Men") aus dem Jahr 1967, als die ersten regelmäßigen Radio-Pulse eines Neutronensterns registriert wurden, über die "fossilen Lebensspuren" im Marsmeteoriten ALH 84001, die im Sommer 1996 per PK auf dem Rasen vor dem Weißen Haus verkündet wurden.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat JWSTObservations @JWSTObservation I am now observing TRAPPIST-1 using MIRI Imaging for 3 hours and 21 minutes. Keywords: M dwarfs, M stars. Proposal: https://stsci.edu/jwst/phase2-public/2304.pdf 2:1 1:17 PM · Nov 30, 2022·JWSTObservation
Zitat JWST Proposal 2304 (Created: Friday, October 21, 2022 at 3:02:21 PM Eastern Standard Time) - Overview
2304 - Hot Take on a Cool World: Does Trappist 1c Have an Atmosphere?
Rocky exoplanets are abundant in the Galaxy. However, it is still unknown how often, and under what conditions, these small worlds can maintain atmospheres. Here we propose to measure thermal emisssion from the dayside of TRAPPIST-1c, a terrestrial exoplanet with temperature similar to that of Venus. This planet is the coolest rocky world with thermal emission that can be detected with JWST. Our observations will constrain the planet's surface pressure and the atmospheric carbon dioxide abundance, and distinguish at 4 sigma confidence between a bare rock planet and a Venus-like composition. The presence of a thick atmosphere would be a positive indicator that the TRAPPIST-1 planets formed in a volatile-rich environment, motivating an aggressive observing program for the cooler, potentially habitable planets in this remarkable system.
OBSERVING DESCRIPTION Our observations consist of time series photometry during four eclipses of the planet TRAPPIST-1c. For each eclipse, the observations will be performed with the MIRI F1500W filter and must be executed in a continuous sequence. Each of the four visits must be timed to coincide with eclipses of the planet (which occur approximately every 2.4 days.)
Zitat NEWS 14 December 2022 - JWST gets first glimpse of 7-planet system with potentially habitable worlds
The James Webb Space Telescope (JWST) has gotten its first look at a hotly anticipated set of targets — the atmospheres of some of the seven Earth-sized planets circling the star TRAPPIST-1, just 12 parsecs (39 light-years) from Earth. All seven lie in or near their star’s habitable zone, where liquid water could exist, and astronomers consider them the best known laboratory for studying what makes planets beyond the Solar System suitable for life.
What researchers have seen so far is preliminary and doesn’t yet indicate what sorts of atmospheres these planets might actually have. But if they have dense atmospheres with intriguing molecules such as carbon dioxide or methane, the US$10-billion telescope will be able to detect them in the coming months and years. No other observatory has been powerful enough to spot these atmospheres.
“We’re in business,” Björn Benneke, an astronomer at the University of Montreal, said during a symposium on first results from JWST in Baltimore, Maryland, on 13 December.
Benneke showed the first JWST studies of TRAPPIST-1g. So far, the telescope has been able to make out that it probably doesn’t have a hydrogen-rich atmosphere — which would be relatively easy to spot because it is so physically large. That could mean that the planet has a denser atmosphere, made of heavier molecules, such as carbon dioxide, or no atmosphere at all.
JWST studies planetary atmospheres primarily by watching how they filter starlight shining through them as they pass in front of the star. Which molecules make up a planet’s atmosphere can indicate how it evolved and whether it might have life on its surface. It will take more observations and time to analyse the data so far collected, before researchers will know if TRAPPIST-1g has an atmosphere, and if so what it is made of.
The TRAPPIST-1 data are much harder to analyse than those gathered from larger exoplanets, including WASP-39b, a planet closer to the size of Jupiter that JWST has studied in detail. TRAPPIST-1’s planets are much smaller, and the signal from their atmospheres more difficult to tease out. Magnetic disturbances in TRAPPIST-1 can also induce signals that confound interpretations of the data.
In a poster presentation at the conference, Olivia Lim of the University of Montreal showed two JWST observations of the innermost planet in the system, TRAPPIST-1b. She, too, has not been able to tease out a signal indicating the planet’s atmosphere just yet. But preliminary studies suggest that it, like planet 1g, probably doesn’t have a puffy, hydrogen-rich atmosphere.
Lim has several more observations of other TRAPPIST-1 planets already in-hand, including one taken last week that she hasn’t had time to look at yet in the crush of JWST results. “It’s hectic,” she says.
But more results on the extraordinary planetary system are on the way, Colón says: “Within the next year we’ll have a family portrait.”
Kleine Adnote noch zu TRAPPIST-1 aus anderer Schiene.
Zitat von October 27, 2022SOLAR FLARES MIGHT ACTUALLY INCREASE HABITABILITY OF TRAPPIST-1 EXOPLANETS
A new study claims solar flares may actually make the planets in Trappist-1’s habitability zone even more habitable than first thought.
According to the new study published in the journal Astronomy and Astrophysics, Trappist-1 periodically emits massive solar flares that blast the planets within the system with high-energy particles and solar radiation. Many researchers have suggested that the intense types of solar flares that are common to red dwarf stars may eventually strip away an exoplanet’s atmosphere, leaving it ill-equipped to sustain life as we know it.
However, the authors of this study suggest that these flares may actually aid the habitability of the planets within the Trappist-1 system by offering the planets more energy to fuel the pre-biotic soup of amino acids, peptides, and other chemicals most believe to be the precursors to the first, most primitive forms of life that first formed on Earth over 3 billion years ago.
Ein Problem, das ich immer mit dem Begriff "habitable Zone" habe ist, dass implizit damit immer gemeint ist "habital im Erd-Sinne".
Die Suche nach außerirdischem Leben wird so durch die eigenen Prämissen ggf. viel zu stark beschränkt.
Es wäre ja schließlich auch Leben vorstellbar auf Planeten, die für uns nicht habitabel wären. Der Saturn-Mond Titan befindet sich z.B. außerhalb der "habitablen Zone" der Sonne. Trotzdem hat er unterirdische Ozeane aus flüssigem Wasser. (die durch Gzeiten-Kräfte erwärmt werden). Und es sind auch Lebensformen vorstellbar, die nicht auf Wasser angewiesen sind, sondern in einem anderen flüssigen Medium existieren können. Zudem wird die Temperatur eines Planeten ja nicht nur von der Entfernung zur Sonne bestimmt, sondern auch von anderen Faktoren wie Gezeitenkräfte (siehe Titan) oder Dichte der Atmosphäre (siehe z.B. Venus). Das sind aber Faktoren, die man aber Stand heute für Exoplaneten nicht von der Erde aus bestimmen kann.
Jetzt mal abgesehen davon, dass u.U. ja auch gar nicht ein Exoplanet lebenstragend sein muss, sondern vielleicht auch nur einer seiner Monde. Viele der frühen Exoplanet-Entdeckungen waren ja große Gasplaneten, für die Leben (wie wir es kennen) eher unwahrscheinlich ist. Aber in vielen Fällen werden diese Gasplaneten Monde haben, die wir mit unseren bisherigen Mitteln nicht entdecken können.
Wir sollten im Hinterkopf behalten, daß nicht einmal die Erde innerhalb der "Goldilocks-Zone" liegt. Ohne den kumulierten Treibhauseffekt (CO2, Wasserdampf, Methan) würden die globalen Temperaturen um gut 30 Grad niedriger liegen und sich auf -18°C belaufen. Nun sind in Gedankenexperimenten und in Weltentwürfen in der spekulativen Literatur ja schon so ziemlich alle Möglichkeiten ausgelotet worden, die das doch recht eng begrenzte Sortiment an chemischen Elementen anbietet, um Leben, so wie man es sinnvoll definieren kann, zu ermöglichen (reproduziert sich, interagiert mit seiner Umwelt, sollte so etwa wie einen Stoffwechsel haben, um sich im Disequilbrium zu halten & Reproduktion zu ermöglichen). Als Basis wird neben Kohlenstoff am meisten Silizium als chemische Basis postuliert; das hat aber den Nachteil, daß die resultierenden Molekülketten praktisch inelastisch sind; im Gegenteil zu den Benzolketten etwa. Als flüssiges Trägermedium ist Methan vorgeschlagen worden. Nur sind bei Temperaturen um -150°C die Bedingungen die die komplexe Chemie, die wir als organisch bezeichnen, eher nicht gegeben; bei höheren Temperaturen halten sich keine komplexen Verbindungen stabil. Zudem läßt sich aus den Entdeckungen von Exoplaneten der letzten 27 ableiten, daß solche Lebensbedingungen, wir sie für organisches Leben auf Kohlenstoffbasis benötigt werden, gar nicht so selten vorkommen, im galaktischen Maßstab gesehen. Bei Planeten von TRAPPIST-1 a-h oder Monden von Gasriesen kommt ein anderes Problem hinzu: diese Umgebung STRAHLT förchterlich, die Mutterkörper, um die das rotiert, haben Magnetsphären, die alles andere als gesund sind. Dort könnte sich Leben nach allem, was wir wissen, nur unter dicken Eispanzern entwickeln. Die haben wir zwar bei zahlreichen Monden unserer Gasriesen im Solsystem; aber ist aber eine völlig ungeklärte Frage, ob eine mit Salzen gesättigte Lake unter hunderten Atmosphären Druck in ewiger Finsternis eine gute Wiege ist. (In den irdischen Tiefseebruchzonen dient dort Schwefel als Treibstoff statt Sonnenlicht; aber bei diesen lebensformen handelt es sich nicht um dort entstandene, sondern evolutiv Reingeschmeckte von außen.)
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Vielleicht hatten die Astrologen ja doch recht: ferne Gestirne haben doch Einfluß auf irdisches Geschehen.
Zitat Google shares fall sharply after AI chatbot debut stumbles - Ad error draws scrutiny as tech group tries to regain edge in search technology
Shares of Google parent Alphabet were down more than 8 per cent on Wednesday, wiping billions of dollars off its market value, as Wall Street digested the potential damage to its search dominance and profits from a new artificial intelligence battle with Microsoft. The knock to its stock price came as a result of a glitch in a Google AI demonstration, highlighting the challenges the company faces in bringing a new style of chat-based search to a mass market.
On Monday Google said it would launch its own chatbot named Bard in an attempt to make up ground lost to rival ChatGPT, though it has not said when the service will be made public. Experts pointed out that Bard had made a factual error in the first video demo of the product online. An animation shared by Google showed Bard answering a question about new discoveries made through the James Webb Space Telescope, saying it “took the very first pictures of a planet outside of our own solar system”. Astronomers said this was incorrect, highlighting a larger issue with search powered by AI known as large language models: that they can confidently make factual mistakes and spread misinformation. One astronomer pointed out the problem could stem from AI misinterpreting “ambiguous Nasa press releases that underplayed past history”.
The glitch highlighted a common flaw with so-called generative AI systems such as Bard, which do not “understand” the information they regurgitate but make guesses based on probability. Microsoft admitted to similar challenges with its chat-based service.
Zitat Aayush Saxena @aaysaxena GN-z11, the record holder for the most distant galaxy for the longest time, now has a STUNNING JWST SPECTRUM full of BOOMING emission lines! Confirmed redshift of 10.6!!
9:19 AM · Feb 15, 2023 · LOOK AT ALL THOS EMISSION LINES, this is absolutely mind boggling stuff
What else? THERE IS LYMAN ALPHA EMISSION! At redshift beyond 10! And it is spatially extended!
The craziness never stops
This paper has been a tremendous team effort, and this spectrum is one of the most spectacular JWST results to date for me. The power of this telescope is immense.
Thanks to Pascal Oesch and team for this galaxy, we are truly standing on the shoulders of giants!
Zitat Thomas Zurbuchen@Dr_ThomasZ This @nasawebb spectrum, perhaps the best I have seen in this field, is in every way as important - and perhaps more - than the beautiful images we have fallen in love with. It proves, by identifying specific atomic lines, how fast the galaxy is moving away from us. History made! 7:46 PM · Feb 15, 2023
Zitat [Submitted on 14 Feb 2023 "JADES NIRSpec Spectroscopy of GN-z11: Lyman-α emission and possible enhanced nitrogen abundance in a z=10.60 luminous galaxy"
We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate z>10 Lyman break galaxy in the GOODS-North field with MUV=−21.5. We derive a redshift of z=10.603 (lower than previous determinations) based on multiple emission lines in our low and medium resolution spectra over 0.8−5.3μm. We significantly detect the continuum and measure a blue rest-UV spectral slope of β=−2.4. Remarkably, we see spatially-extended Lyman-α in emission (despite the highly-neutral IGM expected at this early epoch), offset 555 km/s redward of the systemic redshift. From our measurements of collisionally-excited lines of both low- and high-ionization (including [O II] λ3727, [Ne III] λ3869 and C III] λ1909) we infer a high ionization parameter (logU∼−2). We detect the rarely-seen N IV] λ1486 and N III]λ1748 lines in both our low and medium resolution spectra, with other high ionization lines seen in low resolution spectrum such as He II (blended with O III]) and C IV (with a possible P-Cygni profile). Based on the observed rest-UV line ratios, we cannot conclusively rule out photoionization from AGN. The high C III]/He II ratios, however, suggest a likely star-formation explanation. If the observed emission lines are powered by star formation, then the strong N III] λ1748 observed may imply an unusually high N/O abundance. Balmer emission lines (Hγ, Hδ) are also detected, and if powered by star formation rather than an AGN we infer a star formation rate of ∼20−30M⊙yr−1 (depending on the IMF) and low dust attenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkable galaxy with extreme properties seen 430 Myr after the Big Bang.
Warum das wichtig ist? Abgesehen von einem hochaufgelösten Spektrum einer Galaxie aus einer Entfernung von 13,3 Milliarden Lichtjahren dürfte das wichtige Hinweise auf die Population III, also die erste Sterngeneration nach dem Urknall sein. Eins der großen Rätsel der Kosmologie ist zurzeit noch, wann es zu dieser Bildung gekommen ist und wie groß die waren. Da beim Urknall nur Wasserstoff + Helium entstanden sind, gibt es kaum einen Kühlmechanismus für die Gasmassen (bei den späteren hat der Staub diese Funktion); von daher wird angenommen, daß die Sternmassen dieser ersten Sterne immens gewesen sein müssen. Das wiederum führt zu einer extrem kurzen Lebenszeit dieser Sterne, bis sie als Supernovae explodieren und das umgebende interstellare Medium mit den dabei entstandene schweren Elementen anreichern. Sitckstoff (N) + Kohlenstoff (C) sind Endprodukte beim Schalenbrennen solcher schwerer Sterne. Wenn die also im Spektrum einer Galaxie von 430 Mio Jahren nach den Big Bang nachgewiesen werden können, muß es sehr früh zur Bildung der Population III gekommen sein. So mal aus der Lamäng angedacht.
"Les hommes seront toujours fous; et ceux qui croient les guérir sont les plus fous de la bande." - Voltaire
Zitat Andrew @Cosmic_Andrew1 Paper posted in Nature regarding JWST discovering massive early galaxies that previously were thought not possible to form that early in the universe. The biggest one in the study is TEN times bigger than the Milky Way. 11:11 PM · Feb 22, 2023
Zitat Published: 22 February 2023 "A population of red candidate massive galaxies ~600 Myr after the Big Bang" Ivo Labbé, Pieter van Dokkum, Erica Nelson, Rachel Bezanson, Katherine A. Suess, Joel Leja, Gabriel Brammer, Katherine Whitaker, Elijah Mathews, Mauro Stefanon & Bingjie Wang
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply
Abstract Galaxies with stellar masses as high as ~ 10^11 solar masses have been identified1–3 out to redshifts z ~ 6, approximately one billion years after the Big Bang. It has been difficult to find massive galaxies at even earlier times, as the Balmer break region, which is needed for accurate mass estimates, is redshifted to wavelengths beyond 2.5 μm. Here we make use of the 1-5 μm coverage of the JWST early release observations to search for intrinsically red galaxies in the first ≈ 750 million years of cosmic history. In the survey area, we find six candidate massive galaxies (stellar mass > 10^10 solar masses) at 7.4 ≤ z ≤ 9.1, 500–700 Myr after the Big Bang, including one galaxy with a possible stellar mass of ~10^11 solar masses. If verified with spectroscopy, the stellar mass density in massive galaxies would be much higher than anticipated from previous studies based on rest-frame ultraviolet-selected samples.
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