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These Are The 6 Different Ways To Make A Supernova

“Yet, if you cross a certain mass threshold, you overcome that quantum barrier, and that triggers a runaway fusion reaction, destroying the white dwarfs and leading to a different class of supernova: a thermal runaway supernova.

So, we’ve got core collapse supernovae and thermal runaway supernovae. Does that mean that there are only two classes?

Hardly. There’s more than one way to make both a thermal runaway and a core collapse supernova, and each mechanism or method has properties that are wholly unique to it. Here are the six ways to make a supernova, starting with the least-massive trigger and going up from there.”

So, you’ve got a star, and you want to trigger a supernova with it? Great! Every star that ever gets made in the Universe has the possibility of going supernova. If your star is born with more than about 8 solar masses, it’s practically an inevitability that a supernova will ensue, and that it will be a core-collapse supernova at that. But there are four independent ways to make that happen, and only one of them is the conventional way you probably think about it. If your star has less than 8 solar masses, though, it ends its life in a white dwarf, but that’s not necessarily the end. White dwarfs can gain enough mass, through two different known mechanisms, to someday go supernova as well.

There are six different ways to make a supernova, and each one is spectacular. Which one is your favorite?

Central Cygnus Skyscape via NASA https://ift.tt/2vgpcsn

SpaceTime 20181010 Series 21 Episode 80 is now out

SpaceTime covers the latest news in astronomy & space sciences.

The show is available as a free twice weekly podcast through Apple Podcasts (itunes), Stitcher, Google Podcast, Pocketcasts, SoundCloud, Bitez.com, YouTube, Audio Boom, your favourite podcast download provider, and from www.spacetimewithstuartgary.com

SpaceTime is also broadcast coast to coast across the United States on Science360 Radio by the National Science Foundation in Washington D.C. and around the world on Tune-In Radio.

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Today’s stories…

Another lander touches down on the asteroid Ryugu Japan’s Hyabusa2 spacecraft has successfully deployed a third lander rover onto the rugged boulder strewn surface of the asteroid Ryugu – located some 300 million kilometres from Earth.

New Neutron Star discovery challenges existing theories Existing theories about Neutron stars have taken a blow with astronomers detecting radio jets emanating from a neutron star with a strong magnetic field.

New sub-atomic particles discovered at the super collider Physicists have discovered two new sub atomic particles with hints of a possible third.

Intergalactic stars flying towards the Milky Way Astronomers have discovered dozens of stars flying through intergalactic space heading towards the Milky Way Galaxy.

The Science Report Russia widely condemned over a series of cyber-security attacks. Users demanding higher purity types of ecstasy, crystal methamphetamine, and cocaine. Australia records its driest September on record. Wireless broadband connections the most popular means of accessing the Internet. Alex on tech Prince Charles gives the thumbs down to artificial intelligence.

Last Saturday’s show….

Opportunity still silent Scientists are increasing the frequency of commands being sent to the still silent Opportunity Mars rover on the surface of the red planet.

Neutrino experiment records its first tracks The world’s largest liquid-argon neutrino detector has just recorded its first particle tracks.

One hundredth Ariane 5 launch Arianespace has successfully carried out its 100th Ariane 5 launch.

October Skywatch A busy month with three meteor showers in October–the Draconids, the Taurids and the Orionids.

The Science Report A new class of antibiotics to combat the growing problem of deadly multi-drug resistant bacteria. New solar flow battery that both soaks up sunlight and store it as chemical energy for later use. How bombing air raids during World War Two affected the ionosphere. Warnings that industries dominated by the opposite sex tend to have higher rates of divorce.

SpaceTime Background SpaceTime is Australia’s most respected astronomy and space science news program. The show reports on the latest stories and discoveries making news in astronomy, astrophysics, cosmology, planetary science, galactic and stellar evolution, physics, spaceflight, and general science. SpaceTime features interviews with leading Australian scientists about their latest research. The show is broadcast coast to coast across the United States by the National Science Foundation on Science360 Radio and around the world on Tune in Radio. SpaceTime is available in Australia as a twice weekly podcast which averages around three million downloads annually. It’s hosted on line through Bitez.com on all major podcast platforms. SpaceTime began life in 1995 as ‘StarStuff’ on ABC NewsRadio. Stuart Gary created the show while he was NewsRadio’s Science Editor and evening News anchor. Gary wrote, produced and hosted the program, consistently achieving 9 percent of the Australian radio audience share - according to Neilsen ratings survey figures for the five major Australian metro markets (Sydney, Melbourne, Brisbane, Adelaide, & Perth). The StarStuff podcast was hosted by ABC Science on line achieving over 1.3 million downloads annually. Sadly, the popular program was axed in 2015 during ABC budget cuts. Rather than remain with the ABC, Gary resigned to continue producing the show independently and rebranding it as SpaceTime. The first episode of SpaceTime was broadcast on February 8th 2016 and the show has been in continuous production ever since. SpaceTime now reaches an audience almost three times greater that it achieved as StarStuff and continues to grow.

It’s only two things.

Imagine where you could be by this time next year. Now do the work

This year’s winners of Nobel Prize for Physics includes a woman! 🎉🎊

Her name is Donna Strickland. Together with Arthur Ashkin, and Gérard Mourou, they are awarded the Nobel Prize “for their groundbreaking inventions in the field of laser physics” which help open up doors for potential research in biomedical physics.

[The announcement comes one day after a senior scientist with Cern, the academic home to a number of Nobel prize winners, was suspended for saying that physics was invented and built by men.

“We need to celebrate women physicists because we’re out there. I’m honored to be one of those women,” Strickland said in a news conference following the announcement in Stockholm.

Speaking about being the third woman to ever win the award, she said she thought there might have been more, adding: “Hopefully in time it will start to move forward at a faster rate.”]

Source

Seeing Titan : Shrouded in a thick atmosphere, Saturn’s largest moon Titan really is hard to see. Small particles suspended in the upper atmosphere cause an almost impenetrable haze, strongly scattering light at visible wavelengths and hiding Titan’s surface features from prying eyes. But Titan’s surface is better imaged at infrared wavelengths where scattering is weaker and atmospheric absorption is reduced. Arrayed around this centered visible light image of Titan are some of the clearest global infrared views of the tantalizing moon so far. In false color, the six panels present a consistent processing of 13 years of infrared image data from the Visual and Infrared Mapping Spectrometer (VIMS) on board the Cassini spacecraft. They offer a stunning comparison with Cassini’s visible light view. via NASA

The Orion Bullets via NASA https://ift.tt/2VwwqDm

Interesting facts about stars

Stars are giant, luminous spheres of plasma. There are billions of them — including our own sun — in the Milky Way Galaxy. And there are billions of galaxies in the universe. So far, we have learned that hundreds also have planets orbiting them.

1. Stars are made of the same stuff

All stars begin from clouds of cold molecular hydrogen that gravitationally collapse. As they cloud collapses, it fragments into many pieces that will go on to form individual stars. The material collects into a ball that continues to collapse under its own gravity until it can ignite nuclear fusion at its core. This initial gas was formed during the Big Bang, and is always about 74% hydrogen and 25% helium. Over time, stars convert some of their hydrogen into helium. That’s why our Sun’s ratio is more like 70% hydrogen and 29% helium. But all stars start out with ¾ hydrogen and ¼ helium, with other trace elements.

2. Most stars are red dwarfs

If you could collect all the stars together and put them in piles, the biggest pile, by far, would be the red dwarfs. These are stars with less than 50% the mass of the Sun. Red dwarfs can even be as small as 7.5% the mass of the Sun. Below that point, the star doesn’t have the gravitational pressure to raise the temperature inside its core to begin nuclear fusion. Those are called brown dwarfs, or failed stars. Red dwarfs burn with less than 1/10,000th the energy of the Sun, and can sip away at their fuel for 10 trillion years before running out of hydrogen.

3. Mass = temperature = color

The color of stars can range from red to white to blue. Red is the coolest color; that’s a star with less than 3,500 Kelvin. Stars like our Sun are yellowish white and average around 6,000 Kelvin. The hottest stars are blue, which corresponds to surface temperatures above 12,000 Kelvin. So the temperature and color of a star are connected. Mass defines the temperature of a star. The more mass you have, the larger the star’s core is going to be, and the more nuclear fusion can be done at its core. This means that more energy reaches the surface of the star and increases its temperature. There’s a tricky exception to this: red giants. A typical red giant star can have the mass of our Sun, and would have been a white star all of its life. But as it nears the end of its life it increases in luminosity by a factor of 1000, and so it seems abnormally bright. But a blue giant star is just big, massive and hot.

4. Most stars come in multiples

It might look like all the stars are out there, all by themselves, but many come in pairs. These are binary stars, where two stars orbit a common center of gravity. And there are other systems out there with 3, 4 and even more stars. Just think of the beautiful sunrises you’d experience waking up on a world with 4 stars around it.

5. The biggest stars would engulf Saturn

Speaking of red giants, or in this case, red supergiants, there are some monster stars out there that really make our Sun look small. A familiar red supergiant is the star Betelgeuse in the constellation Orion. It has about 20 times the mass of the Sun, but it’s 1,000 times larger. But that’s nothing. The largest known star is the monster UY Scuti.  It is a current and leading candidate for being the largest known star by radius and is also one of the most luminous of its kind. It has an estimated radius of 1,708 solar radii (1.188×109 kilometres; 7.94 astronomical units); thus a volume nearly 5 billion times that of the Sun.

6. There are many, many stars

Quick, how many stars are there in the Milky Way. You might be surprised to know that there are 200-400 billion stars in our galaxy. Each one is a separate island in space, perhaps with planets, and some may even have life.

7. The Sun is the closest star

Okay, this one you should know, but it’s pretty amazing to think that our own Sun, located a mere 150 million km away is average example of all the stars in the Universe. Our own Sun is classified as a G2 yellow dwarf star in the main sequence phase of its life. The Sun has been happily converting hydrogen into helium at its core for 4.5 billion years, and will likely continue doing so for another 7+ billion years. When the Sun runs out of fuel, it will become a red giant, bloating up many times its current size. As it expands, the Sun will consume Mercury, Venus and probably even Earth. 

8. The biggest stars die early

Small stars like red dwarfs can live for trillions of years. But hypergiant stars, die early, because they burn their fuel quickly and become supernovae. On average, they live only a few tens of millions of years or less.

9. Failed stars

Brown dwarfs are substellar objects that occupy the mass range between the heaviest gas giant planets and the lightest stars, of approximately 13 to 75–80 Jupiter masses (MJ). Below this range are the sub-brown dwarfs, and above it are the lightest red dwarfs (M9 V). Unlike the stars in the main-sequence, brown dwarfs are not massive enough to sustain nuclear fusion of ordinary hydrogen (1H) to helium in their cores.

10. Sirius: The Brightest Star in the Night Sky

Sirius is a star system and the brightest star in the Earth’s night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The system has the Bayer designation Alpha Canis Majoris (α CMa). What the naked eye perceives as a single star is a binary star system, consisting of a white main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, called Sirius B. 

To know more click the links: white dwarf, supernova, +stars, pulsars

sources: wikipedia and universetoday.com

image credits: NASA/JPL, Morgan Keenan, ESO, Philip Park / CC BY-SA 3.0