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  • richardmitnick 1:05 pm on November 30, 2018 Permalink | Reply
    Tags: 2018 ivc- the new supernova, A new supernova in the bright galaxy Messier 77 in Cetus is within range of amateur telescopes, , , , , DLT40 Survey-UC Davis, , Some Type II events leave a neutron star or black hole remnant, Type II supernovae   

    From Sky & Telescope: “Supernova Discovered in the Bright Galaxy Messier 77” 

    SKY&Telescope bloc

    From Sky & Telescope

    November 29, 2018
    Bob King

    A new supernova in the bright galaxy Messier 77 in Cetus is within range of amateur telescopes. Here’s how to find it.

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    New supernova 2018 ivc recently appeared in the bright Messier galaxy M77 located in Cetus at R.A. 2h 42′ 41″, Dec. -00° 00′ 48″. The object is northeast of the core along the edge of the bright inner disk. Koichi Itagaki

    On November 24th, the DLT40 Survey picked up a 15th magnitude supernova in Messier 77, a bright, barred spiral galaxy in Cetus located 50′ southeast of 4th magnitude Delta Ceti. Whenever a supernova is discovered in a Messier galaxy, I get excited. Messiers are among the closer and brighter galaxies and often host supernovae visible in smaller telescopes.

    With an apparent magnitude of 9.6, Messier 77 is easy to find in telescopes as small as 3 inches though a 10-inch or larger scope will be needed to ferret out this supernova — at least at the moment.

    Designated 2018 ivc, the new supernova has brightened to about magnitude 14.5 and appears as a tiny pinprick of light 8.7″ east and 16.1″ north of the center of the galaxy along the edge of the bright inner disk. Spectroscopy reveals the “new star” as a Type II supernova in its early stages, implying that the object could brighten further. Not to throw water on the fire, but intervening dust within the galaxy has dimmed and reddened the explosion, so it’s difficult to predict how bright it might become. One outlier observation from November 25th put it at about magnitude 13.6.

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    Use this map to locate Delta Ceti and the supernova host galaxy, Messier 77. While you’re in the neighborhood, take a look at the variable star Mira, now rising toward maximum with a current magnitude of about 4.0. Stellarium

    This is the first recorded supernova in Messier 77 and though it looks like little more than a faint star in a telescope, the reality is we’re witnessing the collapse and explosion of a highly evolved supergiant star. As you read this, debris from the blast is expanding outward at some 13,500 kilometers per second (30.2 million mph). For perspective, that’s a little more than one Earth-diameter per second! Going along for the ride are the complex elements that were forged in the star’s core and now released into space to seed future generations of stars and their planetary systems.

    3
    “I’ve marked 2018 ivc’s location with a cross in this photograph taken by the Hubble Space Telescope. You can see the object is situated within the galaxy’s dusty inner arms.” NASA / ESA / A. van der Hoeven

    Messier 77 lies 47 million light-years from Earth in Cetus. After all those years of travel, how fortunate that the light from the supernova arrived just in time to track it down without a bright moon and the galaxy well-placed for viewing during evening hours. To find it, start with Menkar (magnitude 2.5), the second brightest star in Cetus, and slide about 2° to the southwest to Delta (δ) Ceti. Set Delta off to one side of the low-magnification field of view and you should see Messier 77 on the opposite side less than a degree to the southeast.

    4
    In a Type II supernova, an aging supergiant star runs out of nuclear fuel to burn in its core, causing a sudden collapse and rebound that rips the star apart. Some Type II events leave a neutron star or black hole remnant. NASA / CXC /M.Weiss

    To dig out the stellar cinder I recommend increasing the magnification to 200x or higher and studying the location along the bright, inner disk for a stellar point — this will be the supernova. Never fear magnification — you may need to go north of 300x depending on whether 2018 ivc brightens further or not. If seeing is poor, it can be difficult to suss out the star in a bright, galactic environment. Try again on another night.

    Coincidentally, the bright comet 46P/Wirtanen passes about 7° southeast of the galaxy on the nights of December 8th and 9th.

    For updates, head over to David Bishop’s excellent Latest Supernovae page and click on the 2018 ivc link. I’ll also update this blog with additional information including my own observation of the supernova which I hope to make tomorrow night.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Sky & Telescope magazine, founded in 1941 by Charles A. Federer Jr. and Helen Spence Federer, has the largest, most experienced staff of any astronomy magazine in the world. Its editors are virtually all amateur or professional astronomers, and every one has built a telescope, written a book, done original research, developed a new product, or otherwise distinguished him or herself.

    Sky & Telescope magazine, now in its eighth decade, came about because of some happy accidents. Its earliest known ancestor was a four-page bulletin called The Amateur Astronomer, which was begun in 1929 by the Amateur Astronomers Association in New York City. Then, in 1935, the American Museum of Natural History opened its Hayden Planetarium and began to issue a monthly bulletin that became a full-size magazine called The Sky within a year. Under the editorship of Hans Christian Adamson, The Sky featured large illustrations and articles from astronomers all over the globe. It immediately absorbed The Amateur Astronomer.

    Despite initial success, by 1939 the planetarium found itself unable to continue financial support of The Sky. Charles A. Federer, who would become the dominant force behind Sky & Telescope, was then working as a lecturer at the planetarium. He was asked to take over publishing The Sky. Federer agreed and started an independent publishing corporation in New York.

    “Our first issue came out in January 1940,” he noted. “We dropped from 32 to 24 pages, used cheaper quality paper…but editorially we further defined the departments and tried to squeeze as much information as possible between the covers.” Federer was The Sky’s editor, and his wife, Helen, served as managing editor. In that January 1940 issue, they stated their goal: “We shall try to make the magazine meet the needs of amateur astronomy, so that amateur astronomers will come to regard it as essential to their pursuit, and professionals to consider it a worthwhile medium in which to bring their work before the public.”

     
  • richardmitnick 12:41 pm on January 20, 2018 Permalink | Reply
    Tags: , , , , , , Meteoritic stardust unlocks timing of supernova dust formation, Type II supernovae   

    From Carnegie Institution for Science: “Meteoritic stardust unlocks timing of supernova dust formation” 

    Carnegie Institution for Science
    Carnegie Institution for Science

    January 18, 2018
    Conel Alexander
    Larry Nittler

    Dust is everywhere—not just in your attic or under your bed, but also in outer space. To astronomers, dust can be a nuisance by blocking the light of distant stars, or it can be a tool to study the history of our universe, galaxy, and Solar System.

    For example, astronomers have been trying to explain why some recently discovered distant, but young, galaxies contain massive amounts of dust. These observations indicate that type II supernovae—explosions of stars more than ten times as massive as the Sun—produce copious amounts of dust, but how and when they do so is not well understood.

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    An electron microscope image of a micron-sized supernova silicon carbide, SiC, stardust grain (lower right) extracted from a primitive meteorite. Such grains originated more than 4.6 billion years ago in the ashes of Type II supernovae, typified here by a Hubble Space Telescope image of the Crab Nebula, the remnant of a supernova explosion in 1054. Laboratory analysis of such tiny dust grains provides unique information on these massive stellar explosions. (1 μm is one millionth of a meter.) Image credits: NASA and Larry Nittler.

    New work from a team of Carnegie cosmochemists published by Science Advances reports analyses of carbon-rich dust grains extracted from meteorites that show that these grains formed in the outflows from one or more type II supernovae more than two years after the progenitor stars exploded. This dust was then blown into space to be eventually incorporated into new stellar systems, including in this case, our own.

    The researchers—led by former-postdoctoral fellow Nan Liu, along with Larry Nittler, Conel Alexander, and Jianhua Wang of Carnegie’s Department of Terrestrial Magnetism—came to their conclusion not by studying supernovae with telescopes. Rather, they analyzed microscopic silicon carbide, SiC, dust grains that formed in supernovae more than 4.6 billion years ago and were trapped in meteorites as our Solar System formed from the ashes of the galaxy’s previous generations of stars.

    Some meteorites have been known for decades to contain a record of the original building blocks of the Solar System, including stardust grains that formed in prior generations of stars.

    “Because these presolar grains are literally stardust that can be studied in detail in the laboratory,” explained Nittler, “they are excellent probes of a range of astrophysical processes.”

    For this study, the team set out to investigate the timing of supernova dust formation by measuring isotopes—versions of elements with the same number of protons but different numbers of neutrons—in rare presolar silicon carbide grains with compositions indicating that they formed in type II supernovae.

    Certain isotopes enable scientists to establish a time frame for cosmic events because they are radioactive. In these instances, the number of neutrons present in the isotope make it unstable. To gain stability, it releases energetic particles in a way that alters the number of protons and neutrons, transmuting it into a different element.

    The Carnegie team focused on a rare isotope of titanium, titanium-49, because this isotope is the product of radioactive decay of vanadium-49 which is produced during supernova explosions and transmutes into titanium-49 with a half-life of 330 days. How much titanium-49 gets incorporated into a supernova dust grain thus depends on when the grain forms after the explosion.

    Using a state-of-the-art mass spectrometer to measure the titanium isotopes in supernova SiC grains with much better precision than could be accomplished by previous studies, the team found that the grains must have formed at least two years after their massive parent stars exploded.

    Because presolar supernova graphite grains are isotopically similar in many ways to the SiC grains, the team also argues that the delayed formation timing applies generally to carbon-rich supernova dust, in line with some recent theoretical calculations.

    “This dust-formation process can occur continuously for years, with the dust slowly building up over time, which aligns with astronomer’s observations of varying amounts of dust surrounding the sites of stellar explosions,” added lead author Liu. “As we learn more about the sources for dust, we can gain additional knowledge about the history of the universe and how various stellar objects within it evolve.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    Andrew Carnegie established a unique organization dedicated to scientific discovery “to encourage, in the broadest and most liberal manner, investigation, research, and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile.
    6.5 meter Magellan Telescopes located at Carnegie’s Las Campanas Observatory, Chile

     
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