Podcaster: Richard Drumm
Title: Space Scoop: Radio Red Dwarf Broadcasts All Night and Day
Organization: 365 Days Of Astronomy
Link : astrosphere.org ; http://unawe.org/kids/unawe1609/
Description: Space scoop, news for children.
Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2016, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at signup@365daysofastronomy.org.
Transcript:
This is 365 Days of Astronomy. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.
Today’s story is:
Radio Red Dwarf Broadcasts All Night and Day
Have you ever heard of solar flares? A solar flare is a giant explosion on the surface of the Sun. It blows huge amounts of solar material out into space.
Our album artwork for today’s episode shows a flare erupting on our Sun. It’s the white spot there in the middle throwing out an orange loop of solar material.
This loop is called a prominence because prominences stand out prominently when they are seen on the edge of the Sun and are contrasted against the dark of space.
When they are seen in front of the Sun itself, they are called filaments and are darker than the Sun’s surface. The prominence is composed of charged particles, mostly hydrogen and helium, and do emit light, just not as much as the Sun’s photosphere where the Sun’s visible light comes from.
Today’s story, though, isn’t about the prominence, pretty though it may be, but the white spot, the solar flare. Flares are typically associated with active sunspot regions on our Sun, and we can assume this to be the case on other stars as well.
When some of those charged particles are aimed at Earth and arrive here, they produce beautiful auroras, also known as the northern or southern lights, the aurora borealis and aurora australis.
But the particles can also disturb radio communications or damage electrical power stations and satellites.
Now you would expect the stellar flares on a tiny dwarf star to have less energy than the solar flares on a bigger star like our Sun. But the ALMA radio telescope has discovered extremely powerful flares on a red dwarf star that’s only a tenth as massive as our Sun.
During the flares, that red dwarf, a so-called “ultracool” dwarf, called TVLM 513-46546, shoots out powerful radio waves that have 10,000 times more energy than the radio waves that come from our Sun.
Let’s call it 513 for short, ok?
It was already known that this red dwarf has a very strong magnetic field – a few hundred times stronger than the magnetic field of the Sun. No one knows exactly how this strong field is generated.
It might be related to the fast rotation of the red dwarf: it turns around its axis once every two hours. That’s pretty fast — the rotation period of the Sun is about 25 days.
513 is a small and cool star at a distance of 35 light-years in the constellation Boötes, the herdsman. Because of its low surface temperature, it mainly emits red light, and since it is small and low mass, stars like this get labelled red dwarves.
Nothing personal, mate!
Red dwarf stars are very common in the Milky Way – there may be two hundred billion of them. They are about as large as Jupiter, but much more massive. Again, this one has ten percent of the mass of the Sun.
During a 4-hour long observation of 513, ALMA detected powerful radio waves from the red dwarf star, at a wavelength of about 3 millimeters. These radio waves are produced by the synchrotron process, when very high energy relativistic electrons are sent on a curving path by strong magnetic fields.
There’s only one way this tiny red dwarf could produce such energetic electrons: giant flares must be shooting out of the star non-stop — a continuous solar flare!
Many red dwarf stars have planets, and we can assume this one has them as well. Life on the surface a planet around this star would be quickly wiped out by the huge doses of deadly radiation! So if there’s life there it’s surely underground.
Hey, Here’s A Cool Fact:
Red dwarfs are red because they are not as hot as many other stars. Think of a gas flame: the coolest part of the fire near the top of the flame glows red and the hottest part near the fuel glows blue.
So the hot & cold taps in your kitchen sink have the color assignments backwards! Hot should be blue, not red! Oh well. I suppose plumbers aren’t very good physicists.
Thank you for listening to 365 Days of Astronomy!
End of podcast:
365 Days of Astronomy
=====================
The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!