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Astronomers investigate disappearance of massive star

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June 30 (UPI) — An unstable massive star in the Kinman Dwarf galaxy, located 75 million light-years away, has disappeared, but scientists aren’t sure why or how.

The Kinman Dwarf galaxy, located in the Aquarius constellation, is too far away for astronomers to observe individual stars, but between 2001 and 2011, scientists detected the signatures of a massive, unstable star in the latter stages of its evolution.

In 2019, when astronomers at the European Southern Observatory’s Very Large Telescope and its ESPRESSO instrument focused on the faraway galaxy, there was no sign of a massive star.

Early observations of the star suggest it was a “luminous blue variable” star, measuring some 2.5 million times brighter than the sun at it brightest.

Luminous blue variable stars are known to fluctuate dramatically in their luminosity, but even when they dim, the stars produce spectrographic signatures that can be identified by astronomers. No such signatures were found in the 2019 VLT observations.

“It would be highly unusual for such a massive star to disappear without producing a bright supernova explosion,” lead researcher Andrew Allan, a doctoral student Trinity College Dublin in Ireland, said in a news release.

It’s possible the star dimmed before becoming obscured by thick intergalactic dust, but scientists suggest it’s also possible the star died an unusually quiet death.

“We may have detected one of the most massive stars of the local Universe going gently into the night,” said Jose Groh, an astronomer at Trinity College Dublin. “Our discovery would not have been made without using the powerful ESO 8-metre telescopes, their unique instrumentation, and the prompt access to those capabilities following the recent agreement of Ireland to join ESO.”

To determine the likely fate of the massive star, scientists returned to data collected by the Very Large Telescope’s UVES instrument between 2002 and 2009.

“The comparison of the 2002 high-resolution UVES spectra with our observations obtained in 2019 with ESO’s newest high-resolution spectrograph ESPRESSO was especially revealing, from both an astronomical and an instrumentation point of view,” said Andrea Mehner, staff astronomer at ESO.

The data showed the massive star brightened dramatically during the initial observation period. Luminous blue variable stars are known to shed large amounts of mass during outbursts.

It’s possible the star became a much less luminous version of itself after a period of outbursts — dim enough to be easily obscured by dust.

“Alternatively, the LBV could have collapsed to a massive black hole without the production of a bright supernova,” researchers wrote in the Monthly Notices of the Royal Astronomical Society.

To solve the cosmic mystery, scientists may have to wait until the next generation of powerful new telescopes come online — like the ESO’s Extremely Large Telescope, due to be unveiled in 2025. The ELT will be capable to imaging individual stars in distant galaxies like the Kinman Dwarf.



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‘Invisible’ words reveal common structure among famous stories

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Aug. 7 (UPI) — Storytelling requires a narrative arc, but the trajectory of a dramatic arc isn’t always obvious.

By tracing the abundance of “invisible” words — pronouns, articles and other short words — researchers were able to identify patterns shared by a diversity of stories, from Shakespeare to Spielberg, according to a study published Friday in Science Advances.

“Over the years, these ‘invisible’ words have been found to be related to a whole mess of psychological processes — how people use small words like articles and pronouns tell us about a person’s mental health, thinking style, their social status, and even how well they get along with other people,” study lead author Ryan Boyd told UPI.

“In many ways, it was a natural progression to look at what these words can tell us how the nature of stories,” said Boyd, a lecturer in behavioral analytics at the University of Leeds.

For the study, Boyd and his colleagues used a range of statistical techniques to analyze the abundance and distribution of invisible words in 40,000 fictional texts, including short stories, novels and movie scripts.

The analysis revealed a common structure — a so-called narrative curve — featuring three distinct phases.

During the “staging” phase, authors use prepositions and articles in greater abundance, peppering their prose with “a” and “the.” These words are more useful at the beginning, when authors must set the scene and provide the audience with basic information.

The middle phase is defined by plot progression, which is revealed by a greater abundance of auxiliary verbs, adverbs and pronouns — or interactional language. During this phase, “the house” from the staging phase becomes “her home” or “it.”

During the third phase, cognitive tension is ramped up as the narrative arc reaches a climax. As the author guides the reader or viewer through the process of conflict resolution, cognitive-processing words like “think,” “believe,” “understand” and “cause” begin to crop up in greater numbers.

Researchers found this three-phase narrative shape remained consistent, regardless of a stories length.

“A 25,000 word story has the same shape as a 250 word story,” said Boyd, lead author of the new study. “It seems, then, that we are able to do a good job of structuring our stories in an optimal way regardless of how much space we have to do it in.”

The researchers set up a website showing the shapes of staging, plot progression and cognitive tension in eight texts at The Arc of Narrative website.

The patterns left by invisible words proved both good and bad stories — tales spun by amateurs, as well as professionals — utilize similar structures.

“Our results confirm what people have long believed about stories,” Boyd said. “Like DNA, we knew about it long before we could actually see it and measure it. With these new methods, we are able to see and measure the ‘DNA’ of stories and understand them in more objective, scientific ways.”

According to Boyd, studying the patterns of stories can offer insights into cognitive processes unique to humans.

“What these story shapes seem to tell us is that we have, to some degree, evolved to process information in certain ways,” he said. “We need to understand the ‘who’ and ‘what’ in order to understand the ‘why’ of our everyday lives and the lives of others.”

The authors of the latest story are already mining text for other language patterns that might help researchers determine whether a story-teller is telling the truth, or perhaps reveal the secrets to a “good” story.



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Florida Current study confirms decline in strength of Gulf Stream

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Aug. 7 (UPI) — New research suggests the strength of the Florida Current, which forms the beginning of the Gulf Stream, has weakened considerably over the last century.

The findings, published Friday in the journal Nature Climate Change, corroborate the predictions of several models that suggest the Gulf Stream has slowed over the last several decades.

The Florida Current is a thermal ocean current that flows from west to east around the tip of Florida, joining the Gulf Stream off Florida’s east coast.

Scientists have been tracking the strength of the Florida Current since the early 1980s — not long enough to identify multi-decadal or centennial trends.

To better understand the current’s historical changes, Christopher Piecuch, researcher at the Woods Hole Oceanographic Institution in Massachusetts, decided to study the relationship between coastal sea level and the strength of near-shore currents.

While researchers have only been measuring the Florida Current for a few decades, scientists have been recording sea level data since the early 1900s. Piecuch was able to use the data to predict historic changes in the strength of near-shore currents.

“In the ocean, almost everything is connected,” Christopher Piecuch, sole author of the new study, said in a news release. “We can use those connections to look at things in the past or far from shore, giving us a more complete view of the ocean and how it changes across space and time.”

The statistical analysis performed by Piecuch showed the Florida Current and Gulf Stream are the weakest they’ve been during the last 110 years.

The findings are in agreement with ocean current models that suggest climate change has caused a slowdown of the Atlantic Meridional Overturning Circulation, of which the Gulf Stream is a part.

Piecuch said he hopes his research will help other scientists use coastal current data to study changes in bigger currents like the Gulf Stream.

“If we can monitor something over the horizon by making measurements from shore, then that’s a win for science and potentially for society,” he said.



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SpaceX, ULA win large government launch contracts

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Astronauts make round trip to space station from U.S. soil

NASA astronaut Douglas Hurley (C) waves to onlookers as he boards a plane at Naval Air Station Pensacola to return him and NASA astronaut Robert Behnken home to Houston a few hours after the duo landed in their SpaceX Crew Dragon Endeavour spacecraft off the coast of Pensacola, Fla,, on August 2, 2020. Photo by Bill Ingalls/NASA | License Photo



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