New Delhi: Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have, for the first time, discovered the heaviest element ever found within the atmosphere of an exoplanet — barium.
The element was discovered at high altitudes in the atmospheres of the ultra-hot gas giants WASP-76 b and WASP-121 b — two exoplanets, or planets that orbit stars outside our Solar System.
The scientists were surprised to find barium, which is 2.5 times heavier than iron, in the upper atmospheres of WASP-76 b and WASP-121 b.
This unexpected discovery raises questions about what these exotic atmospheres may be like.
The finding is counter intuitive because a heavy element like this is never detected in the upper layers of the atmosphere of planets with such high gravity. The heavier elements should ideally fall into the lower levels of the atmosphere.
WASP-76 b and WASP-121 b are both known as ultra-hot Jupiters as they are comparable in size to Jupiter whilst having extremely high surface temperatures, soaring above 1,000 degrees Celsius. This is due to their close proximity to their host stars, which also means an orbit around each star takes only one to two days.
This gives these planets rather exotic features. In WASP-76 b, for example, astronomers suspect it rains iron.
The fact that barium was detected in the atmospheres of both of these ultra-hot Jupiters suggests that this category of planets might be even stranger than previously thought. Read more.
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Asteroid develops new tail after NASA’s DART impact
Just a month after NASA successfully carried out an impact mission to knock the asteroid moonlet Dimorphos off its course, two tails of dust have been spotted being ejected from the asteroid system.
NASA’s Double Asteroid Redirection Test (DART) was carried out on 26 September on Dimorphos, a small moonlet of Didymos. Current data show that DART shortened Dimorphos’s original 11-hour-and 55-minute orbit around Didymos by about 32 minutes.
Over the past several weeks, observations from NASA’s Hubble Space Telescope have allowed scientists to present a more complete picture of how the system’s debris cloud has evolved over time.
The observations show that the ejected material, or “ejecta”, has expanded and faded in brightness with time after impact, largely as expected. The twin tail is an unexpected development, although similar behavior is commonly seen in comets and active asteroids.
The Hubble observations provide the best-quality image of the double tail to date.
The relationship between the comet-like tail and other ejecta features seen at various times in images from Hubble and other telescopes is still unclear, and is something the investigation team is currently working to understand. Read More.
Scientists discover extracts from a lost astronomical catalogue
Scientists, including those from the CNRS and Sorbonne Université, have found fragments of the Star Catalogue composed by the Greek astronomer Hipparchus during the 2nd century BC.
These texts, which had been erased from a manuscript in the medieval period in order to reuse the pages, were uncovered using multispectral imaging technologies.
Written between 170 and 120 BC by the Greek astronomer Hipparchus, it is the oldest known attempt to determine the precise position of fixed stars by associating them with numerical coordinates.
Until now, this text was known only through the writings of Claudius Ptolemy, another ancient astronomer who composed his own catalogue nearly 400 years after Hipparchus.
This discovery comes from the Codex Climaci Rescriptus — a book made up of parchments that were erased and then rewritten on, also known as a palimpsest. In the past, this Codex contained an astronomical poem in ancient Greek with, among elements of commentary on the poem, fragments of Hipparchus’ Catalogue. This palimpsest text, erased in medieval times, has been revealed through multispectral imaging by teams from the Early Manuscripts Electronic Library, the Lazarus Project and the Rochester Institute of Technology.
The fragments of the Star Catalogue are the oldest known to date and bring major advances in its reconstruction. Firstly, they refute a widespread idea that Claudius Ptolemy’s Star Catalogue is merely a “copy” of Hipparchus’ as the observations of the four constellations are different. Furthermore, Hipparchus’ data are verified to the nearest degree, which would make his catalogue much more accurate than Ptolemy’s, even though it was composed several centuries earlier.
For the research team, this major discovery sheds new light on the history of astronomy in antiquity and on the beginnings of the history of science. Read more.
Methane-eating microbes found assimilating microbes from other organisms
Researchers have found that a methane-consuming microbe called Methanoperedens has genes assimilated from many organisms that allows them to consume methane and greenhouse gases at an increased metabolic rate.
In a study published in Nature, the researchers describe the curious collection of genes within these microbes that they call Borgs
Methanoperedens are a type of archaea — unicellular organisms that resemble bacteria but represent a distinct branch of life — that break down methane in soils, groundwater, and the atmosphere to support cellular metabolism.
Along with other methane-consuming microbes, Methanoperedens live in diverse ecosystems around the world but are believed to be less common than microbes that use photosynthesis, oxygen, or fermentation for energy.
Yet they play an outsized role in Earth system processes by removing methane — the most potent greenhouse gas — from the atmosphere.
Methane traps 30 times more heat than carbon dioxide and is estimated to account for about 30 per cent of human-driven global warming.
The gas is emitted naturally through geological processes and by methane-generating archaea; however, industrial processes are releasing stored methane back into the atmosphere in worrying quantities. Read more.
Ostrich-like dinosaurs roamed in ancient North America
Scientists from North Carolina Museum of Natural Sciences have discovered fossils of an ostrich-like dinosaur called Ornithomimosaurs which grew to enormous sizes in ancient eastern North America.
During the Late Cretaceous Period, North America was split by a seaway into two landmasses: Laramidia to the west and Appalachia to the east. However, fossils from Appalachia are rare, and therefore ancient ecosystems from this region are poorly understood.
In this study, the team described new fossils of Ornithomimosaur dinosaurs from the late Cretaceous Eutaw Formation of Mississippi.
Ornithomimosaurs, the so-called “bird-mimic” dinosaurs, were superficially ostrich-shaped with small heads, long arms, and strong legs. The new fossils, including foot bones, are around 85 million years old, which makes them our rare glimpse into a poorly-known interval of North American dinosaur evolution.
By comparing the proportions of these fossils and the patterns of growth within the bones, the team determined that the fossils likely represent two different species of Ornithomimosaurs, one relatively small and one very large.
They estimate the larger species to have weighed over 800kg, and the individual examined was likely still growing when it died. This makes it among the largest Ornithomimosaurs known.
These fossils provide valuable insights into the otherwise poorly understood dinosaur ecosystems of Late Cretaceous eastern North America. They also shed light on Ornithomimosaur evolution. Giant body sizes and multiple species living side-by-side are recurring trends for these dinosaurs across North America and Asia. Read more.
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