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Tag: astronomy

  • F-type stars show life beyond Earth could be possible

    F-type stars show life beyond Earth could be possible

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    Are there planets that contain life beyond Earth? The answer is maybe, according to a new study from University of Texas at Arlington physicists examining F-type star systems.

    Stars fall into seven lettered categories according to their surface temperature. They also differ in other factors, including mass, luminosity, and radius. F-types are in the middle of the scale, hotter and more massive than our sun.

    These stars are yellowish-white in colour and have surface temperatures of more than 10,000 degrees.

    In the research led by doctoral student Shaan Patel and co-authored by professors Manfred Cuntz and Nevin Weinberg, the physicists presented a detailed statistical analysis of the currently known planet-hosting F-type stars using the NASA Exoplanet Archive.

    The archive is an online exoplanet and star data service that collects data for research.

    The role of F-type stars in categorising planet habitability

    “F-type stars are usually considered the high-luminosity end of stars with a serious prospect for allowing an environment for planets favourable for life,” Dr Cuntz said.

    “However, those stars are often ignored by the scientific community. Although they have a shorter lifetime than our Sun, they have a wider HZ.”

    Patel added: “F-type star systems are important and intriguing cases when dealing with habitability due to the larger HZs.

    “HZs are defined as areas in which conditions are right for Earth-type bodies to potentially host exolife.”

    After excluding systems with little information about planets, the team identified 206 systems of interest.

    In one case, the planet HD 111998, also known as 38 Virginis, is always situated in the HZ. It is located 108 light-years from Earth and is thus considered to be part of the extended Solar System neighbourhood.

    It’s also 18% more massive and has a radius 45% greater than the Sun.

    Future uses of the research

    “In future studies, our work may serve to investigate the existence of Earth-mass planets and also habitable exomoons hosted by exo-Jupiters in F-type stars,” Patel explained.

    Among possible future projects are studies of planetary orbits, including:

    • Cases of part-time HZ planets.
    • Explorations of the relationships between planetary habitability and stellar evolution, including astrobiological aspects.
    • Assessments of exomoons for distinct systems.

    Dr Weinberg concluded: “What makes a study like this possible is the hard work and dedication of the worldwide community of astronomers who have discovered more than 5,000 planets over the last 30 years.

    “With so many known planets, we can now carry out statistical analyses of even relatively rare systems, such as planets orbiting F-type stars, and identify those that might reside in the habitable zone.”

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  • Solar Sails and Comet Tails: How Sunlight Pushes Stuff Around

    Solar Sails and Comet Tails: How Sunlight Pushes Stuff Around

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    During the Age of Sail, ships circled the globe on voyages of discovery and trade. That era ended in the 1800s, when coal-fired steam engines began to replace wind power. Now we may be entering a new age of sail—but this time in space. Reversing history, engines and fuel could be replaced by sails on some spacecraft, pushed not by wind but by sunlight.

    The idea is still in development, but we know it works. Just a few weeks ago, NASA hoisted sail on the most ambitious test craft yet, a satellite called the Advanced Composite Solar Sail System (ACS3). It has a square sail 9 meters wide that allows it to adjust its orbital path.

    Now, to really go somewhere, you’d need a much bigger sail, and a NASA effort to build one spanning 1,650 square meters was abandoned in 2022 as infeasible, given the budget. But that’s an implementation issue, which I’m sure smart humans can solve.

    To be clear, this isn’t like putting photovoltaic panels on your roof to generate electricity. Lots of spacecraft and planetary rovers use those already. These are actually shiny, ultralight sails that are pushed by solar radiation. Well, you might ask: How the heck can light move a physical object?

    Comet Tails

    Good question! After all, when someone says they were “floored” by the beauty of a sunrise, we don’t imagine that they were actually struck down. But light bouncing off a surface really does exert a physical force, small though it may be.

    One example is the tail on a comet. You might think it’s like a contrail thrown off as a comet hurtles through space. Nope. See, comets are basically big dirty snowballs. When one nears the sun, some of that ice turns to gas, releasing clouds of dust. The sun’s light then pushes that dust away in a stream that can stretch for millions of miles—sideways to the comet’s path!

    Speaking of which, there’s a comet approaching right now that may put on a spectacular show in October. It’s called Tsuchinshan–ATLAS, and its tail might even be visible to the naked eye.

    Electromagnetic Waves

    Now, light travels in waves, which are a sort of “moving displacement.” Look at an ocean wave: The water only moves up and down, but that vertical displacement travels horizontally across the surface. It can sure as heck knock you over if you wade into the water.

    But light waves are different from ocean waves or sound waves. Take away the water in the sea and you have no waves to surf on. The same is true for sound: There’s no wave if there’s no atmosphere for it to “wave” in. That’s why space is so weirdly silent.

    Light, on the other hand, can travel through empty space. That’s because, in a sense, a light wave is its own medium. The reason is that it’s actually made up of two waves—there’s an electric field wave and a magnetic field wave. That’s why we call it electromagnetic radiation.

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  • ESO telescope captures detailed infrared map of the Milky Way

    ESO telescope captures detailed infrared map of the Milky Way

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    Astronomers have published a gigantic infrared map of the Milky Way containing more than 1.5 billion objects ― the most detailed one ever made.

    The team monitored the central regions of the Milky Way using the European Southern Observatory’s VISTA telescope for more than 13 years.

    At 500 terabytes of data, this is the largest observational project ever carried out with an ESO telescope.

    “We made so many discoveries that we have changed the view of our galaxy forever,” said Dante Minniti, an astrophysicist at Universidad Andrés Bello in Chile who led the project.

    The infrared map is record breaking

    The infrared map of the Milky Way covers an area of the sky equivalent to 8,600 full moons and contains about ten times more objects than a previous map released by the same team back in 2012.

    It includes newborn stars, which are often embedded in dusty cocoons, and globular clusters—dense groups of millions of the Milky Way’s oldest stars.

    Observing infrared light means VISTA can also spot very cold objects, which glow at these wavelengths, like brown dwarfs (‘failed’ stars that do not have sustained nuclear fusion) or free-floating planets that don’t orbit a star.

    Measuring the luminosity of stars

    The observations began in 2010 and ended in the first half of 2023, spanning a total of 420 nights.

    By observing each patch of the sky many times, the team was able to determine the locations of these objects, track how they move, and determine whether their brightness changes.

    They charted stars whose luminosity changes periodically that can be used as cosmic rulers for measuring distances. This has given us an accurate 3D view of the inner regions of the Milky Way, which were previously hidden by dust.

    The researchers also tracked hypervelocity stars – fast-moving stars that catapulted from the central region of the Milky Way after a close encounter with the supermassive black hole lurking there.

    Future exploration of the Milky Way

    The infrared map of the Milky Way contains data gathered as part of the VISTA Variables in the Vía Láctea (VVV) survey and its companion project, the VVV eXtended (VVVX) survey.

    Roberto Saito, an astrophysicist at the Universidade Federal de Santa Catarina in Brazil and lead author of the study, commented: “The project was a monumental effort, made possible because a great team surrounded us.”

    The VVV and VVVX surveys have already led to more than 300 scientific articles. With the surveys now complete, the scientific exploration of the gathered data will continue for decades to come.

    Meanwhile, ESO’s Paranal Observatory is being prepared for the future. VISTA will be updated with its new instrument, 4MOST, and ESO’s Very Large Telescope (VLT) will receive its MOONS instrument.

    Together, they will provide spectra of millions of Milky Way objects surveyed, with countless discoveries to be expected.

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  • Planet in the 'forbidden zone' of dead star could reveal Earth's fate

    Planet in the 'forbidden zone' of dead star could reveal Earth's fate

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    A distant planet should have been consumed when its star expanded to become a red giant, perhaps offering insights into planetary migration

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  • Hubble Space Telescope unearths surprising black hole discoveries

    Hubble Space Telescope unearths surprising black hole discoveries

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    The Hubble Space Telescope has unearthed surprising discoveries about black holes in the early universe, revealing a greater number than previously believed.

    These black holes, found in galaxies less than a billion years after the Big Bang, are more massive and formed from collapsing massive stars. Hubble’s observations provide critical insights into the relationship between black hole growth and galaxy evolution, offering clues about the structure and behaviour of galaxies.

    This breakthrough underscores the importance of continuous astronomical research and Hubble’s advanced capabilities in enhancing our understanding of cosmic history. Discovering more about these findings can offer a deeper appreciation of the universe’s early days.

    Discovery of early black holes

    In a groundbreaking revelation, the Hubble Space Telescope has unearthed a greater number of black holes in the early universe than previously documented.

    These Hubble discoveries provide invaluable insights into black hole formation and galaxy evolution, enhancing our understanding of cosmic history.

    Scientific research indicates that black holes, found in galaxies less than a billion years after the Big Bang, are more massive than expected. This suggests that black holes formed from the collapse of massive, pristine stars during the first billion years of cosmic time.

    Black holes and galaxy evolution

    Black holes serve as key players in the lifecycle of galaxies, influencing their evolution in profound ways. These enigmatic entities are central to many black hole mysteries that researchers are working diligently to uncover.

    Observations with the Hubble Space Telescope have shed light on the intricate galactic connections between black holes and their host galaxies. By studying the relationship between black hole growth and galaxy formation, scientists can refine their models of galaxy evolution.

    ©shutterstock/Nazarii_Neshcherenskyi

    The early formation of black holes, as revealed by Hubble, plays a vital role in this complex puzzle, helping to explain how galaxies achieve their current structure and behaviour. Understanding these connections is essential for constructing accurate models of the universe’s evolutionary history.

    Methods of black hole formation

    The formation of black holes in the early universe is a subject of intense scientific investigation, as it holds the key to understanding the broader mechanisms of cosmic evolution.

    There are several methods by which black holes can form:

    1. Collapsing massive stars: The collapse of massive, pristine stars in the early universe can lead to black hole formation.
    2. Primordial black holes: These hypothetical black holes could have formed in the first few seconds after the Big Bang.
    3. Collapsing gas clouds: Large gas clouds can collapse under their own gravity to form black holes.
    4. Galactic mergers: Mergers of stars in massive clusters can result in the formation of black holes.

    These mechanisms contribute significantly to our understanding of galaxy evolution and cosmic history.

    Importance of the Hubble Telescope

    The Hubble Space Telescope has been a cornerstone of astronomical research for over three decades, continuously delivering groundbreaking discoveries that have revolutionised our understanding of the universe.

    Hubble’s impact extends far beyond the identification of celestial bodies; it has elucidated black hole mysteries that were once incomprehensible.

    Through its advanced observational capabilities, Hubble has enabled scientists to detect black holes in the early universe, shedding light on their formation and evolution.

    This international collaboration between NASA and ESA, managed by the Goddard Space Flight Center, ensures that Hubble remains a pivotal tool in the quest for knowledge.

    Its contributions have fundamentally shaped our comprehension of cosmic phenomena, making it indispensable in the world of space exploration.

    The recent discoveries by the Hubble Space Telescope have significantly impacted the understanding of early black holes and their role in galaxy evolution.

    These findings challenge existing theories about supermassive black hole formation, revealing greater masses than previously anticipated.

    The precision of Hubble’s observations underscores its importance in refining galaxy formation models.

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  • Black hole’s jets are so huge that they may shake up cosmology

    Black hole’s jets are so huge that they may shake up cosmology

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    Illustration of the giant black hole jets known as Porphyrion

    Illustration of the giant black hole jets known as Porphyrion

    Caltech

    A pair of jets blasting out of a black hole spans 23 million light years, the equivalent of 220 Milky Way galaxies in length. This is so large that it may change our understanding both of black holes and the structure of the universe.

    “If you think of jets as a thing, then you could say this is the largest object that we know of in the universe,” says Martin Hardcastle at the University of Hertfordshire, UK.

    The jets, which Hardcastle and his colleagues have named Porphyrion, come from a black hole in a distant galaxy, some 7.5 billion light years from Earth. The light reaching us from them now started its journey when the universe was just 6.3 billion years old, only about half the age it is now.

    The researchers identified the jets, as well as at least 10 other sets of jets that are also millions of light years across, using the Low Frequency Array (LOFAR) telescope, which consists of thousands of radio antennas across many European countries. Follow-up observations using telescopes in India and Hawaii then helped to locate the host galaxy.

    To produce such vast jets, the black hole responsible would have needed to ingest about a sun’s worth of matter each year for a billion years, says Hardcastle. As matter falls into the black hole over this time frame, some of it will be twisted and accelerated by the black hole’s magnetic field, blasting it out into space to form the jets.


    In the early universe, matter was more closely bunched together than it is in our current cosmos, which makes the persistence of the jets over such a long time period without being interrupted by another cosmological object unusual, says Hardcastle. “This is back in a period of the universe where galaxies are quite active. There’s a lot going on, and yet this black hole has managed just to keep blasting away more or less unchecked for a billion years,” he says.

    “I would have thought something like this was impossible,” says Laura Olivera-Nieto at the Max Planck Institute for Nuclear Physics in Germany. “Simply because it seems too big to have maintained the [jet] for so long.”

    Even simulating how such a vast beam formed or what its effects might be is extremely difficult because of the distances involved, she says. “It’s truly a challenge to try to understand how this is physically possible. We cannot put it in a computer, it’s too big.”

    Porphyrion extends so far that it could affect the formation of other galaxies, injecting energy and magnetic fields into other regions, says Hardcastle. This could also help explain the mystery of where the universe gets its magnetic fields from. “It dumps energy and magnetic fields and particles into the voids between the galaxies,” says Hardcastle. “That’s a mechanism for transporting magnetic fields from very, very small scales to very large scales.”

    These jets might also shake up some cosmological theories, which assume that objects like black holes don’t have influence across so much of the universe.

    “A result like this one shows that if you want to understand how the universe’s large-scale structure forms and evolves, you then also have to think about how the smaller components of it, like the systems that would make such an outflow, influence it,” says Olivera-Nieto.

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  • How to View the ‘Comet of the Century’ C/2023 A3

    How to View the ‘Comet of the Century’ C/2023 A3

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    This story originally appeared on WIRED en Español and has been translated from Spanish.

    C/2023 A3, also known as Tsuchinshan–ATLAS and considered “the comet of the century,” will appear in all its splendor in our sky during September and October 2024. Due to its characteristics, astronomers believe it will be exceptionally bright, similar to Halley’s comet in 1986 or NEOWISE in 2020.

    Comets like C/2023 A3 are balls of frozen gases, rocks, and dust that orbit the sun. They are often spectacular because of two physical phenomena that occur during their journey.

    The first is the tail, which stretches out from the nucleus of the comet as it gets closer to the star that it’s orbiting. Solar radiation from the star—in our case the sun—vaporizes some of the comet’s frozen material, blowing gas and dust away from the nucleus that then reflects the star’s light. As a comet gets closer to its star, it’s tail grows in size because of the increase in solar radiation.

    The second phenomena is the comet’s coma. This is an envelope of sublimated ice that forms a kind of atmosphere around the nucleus as it approaches its star, again because of solar radiation. This also enhances the comet’s brightness.

    What Is the Best Day to See the Comet?

    C/2023 A3 will shine in the northern hemisphere sky from September 27 and will remain visible until the last week of October. During this period, the comet will reach its minimum distance from the sun, before beginning its journey back out of the solar system.

    According to the specialized blog Cometography, the day when C/2023 A3 will shine the brightest will be October 2. The comet’s tail will be long and spectacular at this point due to its proximity to the sun.

    Simulación del viaje del cometa del siglo en septiembre y octubre.

    Tsuchinshan–ATLAS will be positioned between the orbits of Mercury and Venus when it is most visible, but will be closer to Earth than those two planets.

    Cometografía

    At What Time Will the Comet Be Visible?

    Because of its proximity to the sun, the comet will behave similarly to Mercury and Venus: It will be seen near the horizon, in the path of the sun, and just before sunrise. An appropriate window to admire it will be between 5 am and 7 am from September 27 onwards. The timing and position will be similar across the northern hemisphere.

    As October progresses, the comet will elevate its position in relation to the horizon and at the same time lose brightness. Since Tsuchinshan–ATLAS is a long-orbiting body and comes from the Oort cloud, beyond the edge of the solar system, it will not appear again in our skies for tens of thousands of years.

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  • Bubbles of gas 75 times larger than our sun spotted on another star

    Bubbles of gas 75 times larger than our sun spotted on another star

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    The motion of bubbling gas on the surface of the star R Doradus

    The motion of bubbling gas on the surface of the star R Doradus

    ALMA (ESO/NAOJ/NRAO)/W. Vlemming

    Giant bubbles of hot gas more than 75 times the size of our sun have been observed on the surface of a nearby star, which researchers say may lead to better solar computer simulations.

    Wouter Vlemmings and his colleagues at Chalmers University of Technology in Gothenburg, Sweden, hoped to observe R Doradus, which is 178 light years from Earth and 350 times larger than the sun, to better understand how matter is ejected from ageing stars.

    Vlemmings says they booked time with the Atacama Large Millimeter/submillimeter Array (ALMA) observatory in Chile, where only one in seven applications make it, to collect a single snapshot observation.

    The first two attempts were hindered by Earth weather conditions, so only the third met the strict quality criteria set out in the researchers’ application for observatory time. But this meant they accumulated multiple images, which Vlemmings says were actually all usable, allowing the team to plot movement over time.


    Not only was this the first time such bubbles have been observed in detail outside our solar system, but the images also formed a sort of flipbook, allowing the researchers to gauge speed as well as size. “That was a bonus,” says Vlemmings. “We didn’t plan for it, and certainly we didn’t expect that it would all fall into place [this way].”

    They also found that the giant bubbles of gas, measuring more than 100 million kilometres from side to side, were surfacing and then sinking back into the star’s interior faster than expected.

    Nuclear fusion reactions inside stars create convection currents, where hot bubbles of gas rise to the surface before cooling and sinking towards the core. It is thought that this process is responsible for ejecting matter that then escapes a star’s gravity and spreads out into the cosmos to form new stars and planets. It now seems that it occurs three to four times faster than predicted, at least in R Doradus, where the bubbles form and disappear over around one month.

    The region around R Doradus

    The region around R Doradus

    ESO/Digitized Sky Survey 2

    Convection on stars has been modelled with computers for some time, but these models now appear to be slightly lacking because the movement isn’t as fast as has now been observed in the real world, says Vlemmings.

    “There seems to be something missing a little bit, because these bubbles are a little bit faster than was predicted,” he says. “For a long time in our field, the models have basically been ahead of the observations, but we’ve actually never had the observations to test if those models were right.”

    R Doradus hadn’t been the focus of much research in the past because it can only be seen from the southern hemisphere and, historically, most of the large radio telescopes were in the northern hemisphere. But Vlemmings says this has changed with ALMA. It also produces such comprehensive data that he expects more remains to be found. The researchers hope to observe similar stars next year to see if they can find the phenomenon elsewhere.

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  • Astronomers worried by launch of five new super-bright satellites

    Astronomers worried by launch of five new super-bright satellites

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    Five satellites due to launch this week could be brighter than most stars, and astronomers fear the growth of such constellations could have a catastrophic impact

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  • Astronomers puzzled by little red galaxies that seem impossibly dense

    Astronomers puzzled by little red galaxies that seem impossibly dense

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    JWST images of little red dot galaxies

    Josephine F.W. Baggen et al. (2024)

    Strangely bright galaxies spotted by the James Webb Space Telescope (JWST), called “little red dots”, may have more stars packed into them than any other galaxies we know of. The density appears so high that it’s unclear how the stars even survive without crashing into their neighbours, challenging astronomers’ best ideas of how galaxies grow.

    Shortly after JWST started searching the extremely distant universe in 2022, astronomers started to see extremely bright and red, but apparently tiny, galaxies, which they called little red dots…

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