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    VIRGOCosmos In Brief - Aktualní novinky vesmírného výzkumu v kostce




    For every complex question, there's a simple answer that's completely wrong.
    rozbalit záhlaví
    JULIANNE
    JULIANNE --- ---
    VIRGO: Vida, to už vyšlo! Vera Dobos byla na Geosciences for Understanding Planetary Habitability in The Solar System and Beyond, and Lena Noack se jí celkem případně ptala na to, jestli plánuje zahrnout indukční ohřev, já snad na to, jestli přibudou slapové interakce mezi planetami, nejen hvězda-planeta, a Tomáš Petrásek na atmosférický feedback. Třeba už tam všechno je, jdu se mrknout :).
    VIRGO
    VIRGO --- ---
    TRAPPIST-1 System Planets Potentially Habitable | Planetary Science Institute
    http://www.psi.edu/news/press-releases

    Two exoplanets in the TRAPPIST-1 system have been identified as most likely to be habitable, a paper by PSI Senior Scientist Amy Barr says.

    The TRAPPIST-1 system has been of great interest to observers and planetary scientists because it seems to contain seven planets that are all roughly Earth-sized,
    Barr and co-authors Vera Dobos and Laszlo L. Kiss said in “Interior Structures and Tidal Heating in the TRAPPIST-1 Planets” that appears in Astronomy & Astrophysics.

    “Because the TRAPPIST-1 star is very old and dim, the surfaces of the planets have relatively cool temperatures by planetary standards, ranging from 400 degrees Kelvin
    (260 degrees Fahrenheit), which is cooler than Venus, to 167 degrees Kelvin (-159 degrees Fahrenheit), which is colder than Earth’s poles,” Barr said. “The planets also
    orbit very close to the star, with orbital periods of a few days. Because their orbits are eccentric –not quite circular – these planets could experience tidal heating
    just like the moons of Jupiter and Saturn.”

    “Assuming the planets are composed of water ice, rock, and iron, we determine how much of each might be present, and how thick the different layers would be. Because
    the masses and radii of the planets are not very well-constrained, we show the full range of possible interior structures and interior compositions.” Barr said. The team’s
    results show that improved estimates of the masses of each planet can help determine whether each of the planets has a significant amount of water.

    The planets studied are referred to by letter, planets b through h, in order of their distance from the star. Analyses performed by co-author Vera Dobos show that planets
    d and e are the most likely to be habitable due to their moderate surface temperatures, modest amounts of tidal heating, and because their heat fluxes are low enough to
    avoid entering a runaway greenhouse state. A global water ocean likely covers planet d.

    The team calculated the balance between tidal heating and heat transport by convection in the mantles of each planet. Results show that planets b and c likely have
    partially molten rock mantles. The paper also shows that planet c likely has a solid rock surface, and could have eruptions of silicate magmas on its surface driven
    by tidal heating, similar to Jupiter’s moon Io.

    VIRGO
    VIRGO --- ---
    Dust storms linked to gas escape from Martian atmosphere | CU Boulder Today | University of Colorado Boulder
    https://www.colorado.edu/today/2018/01/22/dust-storms-linked-gas-escape-martian-atmosphere

    Some Mars experts are eager and optimistic for a dust storm this year to grow so grand it darkens skies around the entire Red Planet.
    This type of phenomenon in the environment of modern Mars could be examined as never before possible, using the combination of spacecraft now at Mars.

    A study published today and co-authored by CU Boulder scientists looked at observations by NASA's Mars Reconnaissance Orbiter (MRO) during the most recent
    Martian global dust storm. That 2007 event suggests such storms play a role in the ongoing process of gas escaping from the top of Mars' atmosphere,
    a process which long ago transformed wetter, warmer ancient Mars into today's arid, frozen planet.

    "We found there's an increase in water vapor in the middle atmosphere in connection with dust storms," said Nicholas Heavens of Hampton University,
    Hampton, Virginia, lead author of the report in Nature Astronomy. "Water vapor is carried up with the same air mass rising with the dust."

    VIRGO
    VIRGO --- ---
    Johns Hopkins Scientist Proposes New Definition of a Planet « News from The Johns Hopkins University
    http://releases.jhu.edu/2018/01/22/johns-hopkins-scientist-proposes-new-definition-of-a-planet/

    Pluto hogs the spotlight in the continuing scientific debate over what is and what is not a planet, but a less conspicuous argument rages on about the planetary
    status of massive objects outside our solar system. The dispute is not just about semantics, as it is closely related to how giant planets like Jupiter form.

    Johns Hopkins University astrophysicist Kevin Schlaufman aims to settle the dispute.

    In a paper just published in the Astrophysical Journal, Schlaufman has set the upper boundary of planet mass between four and 10 times the mass of the planet Jupiter.

    [1801.06185] Evidence of an Upper Bound on the Masses of Planets and its Implications for Giant Planet Formation
    https://arxiv.org/abs/1801.06185

    Schlaufman, an assistant professor in the university’s Department of Physics & Astronomy, says setting a limit is possible now mainly due to improvements in the technology
    and techniques of astronomical observation. The advancements have made it possible to discover many more planetary systems outside our solar system and therefore possible
    to see robust patterns that lead to new revelations.

    “While we think we know how planets form in a big picture sense, there’s still a lot of detail we need to fill in,” Schlaufman said. “An upper boundary on the masses of
    planets is one of the most prominent details that was missing.”

    The conclusions in the new paper are based on observations of 146 solar systems, systems, Schlaufman said, is the fact that almost all the data he used was measured in
    a uniform way. The data are more consistent from one solar system to the next, and so more reliable.

    Defining a planet, distinguishing it from other celestial objects, is a bit like narrowing down a list of criminal suspects. It’s one thing to know you’re looking for
    someone who is taller than 5-foot-8, it’s another to know your suspect is between 5-foot-8 and 5-foot-10.

    In this instance, investigators want to distinguish between two suspects: a giant planet and a celestial object called a brown dwarf. Brown dwarfs are more massive than
    planets, but less massive than the smallest stars. They are thought to form as stars do.

    For decades brown dwarfs have posed a problem for scientists: how to distinguish low-mass brown dwarfs from especially massive planets? Mass alone isn’t enough to tell
    the difference bzween the two, Schlaufman said. Some other property was needed to draw the line.

    In Schlaufman’s new argument, the missing property is the chemical makeup of a solar system’s own sun. He says you can know your suspect, a planet, not just by his size,
    but also by the company he keeps. Giant planets such as Jupiter are almost always found orbiting stars that have more iron than our sun. Brown dwarfs are not so discriminating.
    VIRGO
    VIRGO --- ---
    Featured Image: New Detail in the Toothbrush Cluster
    http://aasnova.org/2018/01/22/featured-image-new-detail-in-the-toothbrush-cluster/

    This spectacular composite reveals the galaxy cluster 1RXS J0603.3+4214, known as the “Toothbrush cluster” due to the shape of its most prominent radio relic. Featured in a recent publication led by Kamlesh Rajpurohit
    (Thuringian State Observatory, Germany), this image contains new Very Large Array (VLA) 1.5-GHz observations (red) showing the radio emission within the cluster. This is composited with a Chandra view of the X-ray emitting
    gas of the cluster (blue) and an optical image of the background from Subaru data. The new deep VLA data — totaling 26 hours of observations — provides a detailed look at the complex structure within the Toothbrush relic,
    revealing enigmatic filaments and twists (see below). This new data will help us to explore the possible merger history of this cluster, which is theorized to have caused the unusual shapes we see today.

    VIRGO
    VIRGO --- ---
    Scientists find evidence of strong winds outside black holes
    https://www.folio.ca/scientists-find-evidence-of-strong-winds-outside-black-holes/

    New research shows the first evidence of strong winds around black holes throughout bright outburst events in which black holes rapidly consume mass.

    The study sheds new light on how mass transfers to black holes and how they can affect the environment around them.

    “Winds must blow away a large fraction of the matter a black hole could eat,’’ said Bailey Tetarenko, a University of Alberta PhD student and lead author
    on the study. “In one of our models, the winds removed 80 per cent of the black hole’s potential meal.”

    The research was conducted by an international team of researchers, led by Tetarenko and scientists in the U of A's Department of Physics.
    VIRGO
    VIRGO --- ---
    A ‘hot Jupiter’ with unusual winds | Newsroom - McGill University
    http://www.mcgill.ca/newsroom/channels/news/hot-jupiter-unusual-winds-284028

    The hottest point on a gaseous planet near a distant star isn’t where astrophysicists expected it to be –
    a discovery that challenges scientists’ understanding of the many planets of this type found in solar systems outside our own.

    Unlike our familiar planet Jupiter, so-called hot Jupiters circle astonishingly close to their host star -- so close that it typically takes fewer than three days to complete an orbit.
    And one hemisphere of these planets always faces its host star, while the other faces permanently out into the dark. Not surprisingly, the “day” side of the planets gets vastly hotter
    than the night side, and the hottest point of all tends to be the spot closest to the star. Astrophysicists theorize and observe that these planets also experience strong winds blowing
    eastward near their equators, which can sometimes displace the hot spot toward the east.

    In the mysterious case of exoplanet CoRoT-2b, however, the hot spot turns out to lie in the opposite direction: west of center. A research team led by astronomers at McGill University’s
    McGill Space Institute (MSI) and the Institute for research on exoplanets (iREx) in Montreal made the discovery using NASA’s Spitzer Space Telescope. Their findings are reported Jan. 22
    in the journal Nature Astronomy.

    VIRGO
    VIRGO --- ---
    A New Bound on Axionssu201802 | www.cfa.harvard.edu/
    https://www.cfa.harvard.edu/news/su201802

    CfA astronomer Paul Nulsen and his colleagues used a novel method to investigate the nature of axions. Quantum mechanics constrain axions, if they exist, to interact with light in the presence of a magnetic field.
    As they propagate along a strong field, axions and photons should transmute from one to the other other in an oscillatory manner. Because the strength of any possible effect depends in part on the energy of the photons,
    the astronomers used the Chandra X-ray Observatory to monitor bright X-ray emission from galaxies. They observed X-rays from the nucleus of the galaxy M87, which is known to have strong magnetic fields, and which (at
    a distance of only fifty-three million light-years) is close enough to enable precise measurements of variations in the X-ray flux. Moreover, M87 lies in a cluster of galaxies, the Virgo cluster, which should insure
    the magnetic fields extend over very large scales and also facilitate the interpretation. Not least, M87 has been carefully studied for decades and its properties are relatively well known.

    The search did not find the signature of axions. It does, however, set an important new limit on the strength of the coupling between axions and photons, and is able to rule out a substantial fraction of the possible
    future experiments that might be undertaken to detect axions. The scientists note that their research highlights the power of X-ray astronomy to probe some basic issues in particle physics, and point to complementary
    research activities that can be undertaken on other bright X-ray emitting galaxies.
    VIRGO
    VIRGO --- ---
    Update on an Interstellar Asteroid
    http://aasnova.org/2018/01/19/update-on-an-interstellar-asteroid/

    Are we sure ‘Oumuamua didn’t originate in our solar system and get scattered into a weird orbit? Jason Wright (The Pennsylvania State University)
    demonstrates via a series of calculations that no known solar system body could have scattered ‘Oumuamua onto its current orbit — nor could any as
    yet unknown object bound to our solar system.

    Eric Mamajek (Caltech and University of Rochester) shows that the kinematics of ‘Oumuamua are consistent with what we might expect of interstellar
    field objects, though he argues that its kinematics suggest it’s unlikely to have originated from many of the nearest stellar systems.

    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/feature/jpl/asteroid-2002-aj129-to-fly-safely-past-earth-february-4

    Asteroid 2002 AJ129 will make a close approach to Earth on Feb. 4, 2018 at 1:30 p.m. PST (4:30 p.m. EST / 21:30 UTC). At the time of closest approach,
    the asteroid will be no closer than 10 times the distance between Earth and the Moon (about 2.6 million miles, or 4.2 million kilometers).

    2002 AJ129 is an intermediate-sized near-Earth asteroid, somewhere between 0.3 miles (0.5 kilometers) and 0.75 miles (1.2 kilometers) across. It was discovered
    on Jan. 15, 2002, by the former NASA-sponsored Near Earth Asteroid Tracking project at the Maui Space Surveillance Site on Haleakala, Hawaii. The asteroid’s
    velocity at the time of closest approach, 76,000 mph (34 kilometers per second), is higher than the majority of near-Earth objects during an Earth flyby.
    The high flyby velocity is a result of the asteroid’s orbit, which approaches very close to the Sun -- 11 million miles (18 million kilometers). Although asteroid
    2002 AJ129 is categorized as a Potentially Hazardous Asteroid (PHA), it does not pose an actual threat of colliding with our planet for the foreseeable future.

    VIRGO
    VIRGO --- ---
    Comet Discoverer Thomas Bopp (1949–2018) - Sky & Telescope
    http://www.skyandtelescope.com/astronomy-news/people-places-and-events/thomas-bopp-1949-2018/

    An unassuming amateur astronomer forever linked to one of the greatest comets in modern history has passed away.

    Thomas Joel Bopp, the co-discoverer of Comet Hale-Bopp, died January 5, 2018, in Phoenix, Arizona, from liver cancer. He was 68 years old.



    VIRGO
    VIRGO --- ---
    Woow! Launch Of A Epsilon-3 Rocket taken by KAGAYA on January 18, 2018 @ Okinawa Island in Japan

    VIRGO
    VIRGO --- ---
    VIRGO
    VIRGO --- ---
    https://www.utsa.edu/today/2018/01/story/Blackholes.html

    Chris Packham, associate professor of physics and astronomy at The University of Texas at San Antonio (UTSA), has collaborated on a new
    study that expands the scientific community’s understanding of black holes in our galaxy and the magnetic fields that surround them.

    Packham and astronomers lead from the University of Florida observed the magnetic field of a black hole within our own galaxy from multiple
    wavelengths for the first time. The results, which were a collective effort among several researchers, are deeply enlightening about some of
    the most mysterious objects in space.

    VIRGO
    VIRGO --- ---
    JunoCam/Gerald Eichstädt - jižní pól (70.2 km/pix)
    https://www.nasa.gov/image-feature/jpl/pia21975/jupiter-s-swirling-south-pole

    VIRGO
    VIRGO --- ---
    If you live in the western part of North America, Alaska, and the Hawaiian islands,
    you might set your alarm early the morning of Wednesday, Jan. 31 for a lunar trifecta: a pre-dawn “super blue blood moon.”

    https://www.nasa.gov/feature/super-blue-blood-moon-coming-jan-31

    VIRGO
    VIRGO --- ---
    Neutron-star merger yields new puzzle for astrophysicists | Newsroom - McGill University
    http://www.mcgill.ca/...m/channels/news/neutron-star-merger-yields-new-puzzle-astrophysicists-283948

    The afterglow from the distant neutron-star merger detected last August has continued to brighten – much to the surprise of astrophysicists studying
    the aftermath of the massive collision that took place about 138 million light years away and sent gravitational waves rippling through the universe.

    New observations from NASA’s orbiting Chandra X-ray Observatory, reported in Astrophysical Journal Letters, indicate that the gamma ray burst unleashed
    by the collision is more complex than scientists initially imagined.

    “Usually when we see a short gamma-ray burst, the jet emission generated gets bright for a short time as it smashes into the surrounding medium –
    then fades as the system stops injecting energy into the outflow,” says McGill University astrophysicist Daryl Haggard, whose research group led
    the new study. “This one is different; it’s definitely not a simple, plain-Jane narrow jet.”

    VIRGO
    VIRGO --- ---
    Asteroid 2018 BD missed Earth by just 0.10 LD on January 18
    https://watchers.news/2018/01/18/asteroid-2018-bd-missed-earth-by-just-0-10-ld-on-january-18/

    A newly discovered asteroid designated 2018 BD flew past Earth at a very close distance of 0.10 LD / 0.00026 AU (~38 895 km / 24 168 miles) at 15:43 UTC on January 18, 2018,
    some 7 hours after it was discovered. This is the fourth closest approach to our planet since 2017 EA on March 02, 2017, 2017 GM on April 4, 2017, and 2017 UJ2 on Oct 20, 2017.
    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/...goddard/2018/nasa-team-studies-middle-aged-sun-by-tracking-motion-of-mercury

    Like the waistband of a couch potato in midlife, the orbits of planets in our solar system are expanding. It happens because the Sun’s gravitational grip gradually weakens as
    our star ages and loses mass. Now, a team of NASA and MIT scientists has indirectly measured this mass loss and other solar parameters by looking at changes in Mercury’s orbit.

    The new values improve upon earlier predictions by reducing the amount of uncertainty. That’s especially important for the rate of solar mass loss, because it’s related to
    the stability of G, the gravitational constant. Although G is considered a fixed number, whether it’s really constant is still a fundamental question in physics.

    VIRGO
    VIRGO --- ---
    https://www.forbes.com/...interstellar-visitor-oumuamua-was-shaped-by-cosmic-particles/#13fcfd497422

    Last year, the interstellar interloper ʻOumuamua passed through the inner Solar System. Originally thought to be a comet, then later an asteroid, this visitor turned out to have properties
    unlike any object ever seen before. It moved far too quickly and from too inclined an angle to originate from within our Solar System; neither Jupiter nor Neptune nor an Oort cloud object
    could have flung it inwards with those properties. When we examined it in detail, it appeared to have a carbon-based coating over an icy interior, yet sprouted no tail, despite reaching
    temperatures of 550 °F (290 °C). Oddest of all, it was cigar-shaped, approximately eight times as long as it was wide. While many origin theories have been proposed, an incredibly simple
    possibility may provide all the answers: simply traveling through the Milky Way for billions of years may have transformed it into the object we see today.

    VIRGO
    VIRGO --- ---
    Crater Neukum named after Mars Express founder / Mars Express / Space Science / Our Activities / ESA
    http://www.esa.int/...ties/Space_Science/Mars_Express/Crater_Neukum_named_after_Mars_Express_founder

    A fascinating martian crater has been chosen to honour the German physicist and planetary scientist, Gerhard Neukum, one of the founders of ESA’s Mars Express mission.

    he International Astronomical Union named the 102 km-wide crater in the Noachis Terra region “Neukum” in September last year after the camera’s leader, who died in 2014.
    Professor Neukum inspired and led the development of the high-resolution stereo camera on Mars Express, which helped to establish the regional geology and topography of Mars.

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