skytalk

Star light, star (very) bright


Astronomers get their first glimpse of Yellow Hyperstar (HR 5171) one of the 10 largest known stars – 12,000 light years from earth, 1,300x diameter of our star, 1.3 billion miles in diameter. A million times brighter than our sun, it has a companion so close that the two stars touch. This is one of only 12 hyperstars found in our galaxy. Mars Rover Opportunity’s funding runs out next year, unless… NASA’s 2015 budget request shows no funding allocated for the longest running planetary surface explorer. Landed in 2004, has run 24 miles, and found indicators that water was on Mars in the distant past. No worries yet. Twin NASA astronauts Scott and Mark Kelly will be studied to find ways to reduce effects of space travel. Outcomes of physiological and psychological tests will help earth medicine also. Jupiter at dusk, Mars by 10, Saturn by midnight, Venus by 5am, Mercury by 6:30. Winter stars moving to the west at sunset, Spring stars up in the east, summers in the pre-dawn sky.


March 17, 2014

 

[Dave Heller] A very big, very bright and very unusual type of star in our Milky Way is providing astronomers with a snapshot of a heavenly body in transition. Let’s capture it with Derrick Pitts, chief astronomer at the Franklin Institute. And Derrick, how big and how bright?

[Derrick Pitts] It’s so big that if we could fly at standard jet aircraft speed of 550 miles per hour, it would take us 849 years to circumnavigate this star. Around our sun it would only be 205 days.

Wow.

Very big difference.

Very big star.

An incredibly big star. It’s 1,300 times larger than our star is.

So if that star was centered where our sun is now, would we — planet Earth — be inside of that star?

The planets of the solar system would be inside that star out to Jupiter. It’s enormous. And it’s also unusual in that it has a companion. Now, it’s not unusual for stars to have companions, but in this particular case the companion star to this gigantic star is so close that the two actually touch. And if you could, sort of, draw a picture of what it would look like, it would sort of look like a peanut in that you have one large lobe and then one smaller lobe that seem to be connected by some neck that goes between the two.

But still two distinct stars?

They are still two distinct stars, but it just so happens that they’re so close that they can share material, and this is one of the dynamics that can happen between stars when they get close to each other.

This one’s called a yellow hyperstar. We’re a yellow star — not so hyper?

Not so hyper, yes. Our sun is actually what’s called a yellow dwarf. We’re just an average sized star — nothing really big and nothing really small. And in fact, this yellow hyperstar is unusual because stars typically aren’t this size. And stars that are this size tend to be very, very active and they also tend to be very volatile. And their lifespans are not really so long. Now, if we could find enough of them in various stages of their life, we can figure out something about what their evolution is in their lives. But we don’t really know very much yet; we know that this star is volatile, and we know that it is in a state of transition over its life cycle.

It’s interesting — it’s getting larger even as it cools.

Well, and that’s typical for stars. This is what they do: As their surface area increases, that heat has to be distributed over a wider area so the surface temperature goes down. So as we look at stars as they evolve through their life cycles, we find that this is the case. The larger a star gets, the cooler it is. If we look at a star, like Betelgeuse for example. Betelgeuse is a red giant star. It is enormous — truly much bigger than our sun is. But our sun checks in at about 11,000 degrees surface temperature, while Betelgeuse checks in at about 6,000 degrees — slightly cooler in surface temperature.

Let’s look at another bright star that will dim just for a cosmic moment on Thursday.

But not intrinsically will it lose its brightness. It’ll lose its brightness because another object is passing between the Earth and that star. Regulus is the brightest star of the constellation Leo the Lion, a nice spring constellation that we can see in our evening sky. The asteroid itself is going to pass between the Earth and the star at about 2:06 a.m. on Thursday. So if you happen to be up at that time, if you’re in the New York City area, you might actually be able to se — if the sky is clear — the star “wink” out for about 14 seconds and then reappear.

  • Betelgeuse

    Betelgeuse (sounds a lot like “beetle juice”), a red supergiant star about 600 light years distant, is seen in this Hubble Space Telescope image – the first direct picture of the surface of a star other than the Sun. While Betelgeuse is cooler than the Sun, it is more massive and over 1000 times larger. If placed at the center of our Solar System, it would extend past the orbit of Jupiter. Betelgeuse is also known as Alpha Orionis, one of the brightest stars in the familiar constellation of Orion, the Hunter. The name Betelgeuse is Arabic in origin. As a massive red supergiant, it is nearing the end of its life and will soon become a supernova. In this historic image, a bright hotspot is revealed on the star’s surface.Credit: A. Dupree (CfA), R. Gilliland (STScI), NASA

Hey, what are the chances that the funding (or lack thereof) will lead to the Mars rover Opportunity “winking out” on the red planet?

Well we don’t know yet what the chances are for Opportunity on Mars to lose its funding entirely. When we look at the proposed NASA budget for 2015, it indicates that there is no money to be spent on maintaining the rover Opportunity. However, there are ways in which Congress could provide supplementary funding to keep the rover operating and to keep us in contact with it. If you remember, it landed on the surface of Mars in 2004 — now, 10 years ago! With an expected mission lifetime of 3 months, it’s now lasted 10 years. It’s still going, still collecting scientific information, it’s roamed about 24 miles across the surface and provided all kinds of really fabulous firsts for a planetary rover, including being the first to actually discover direct evidence of water found on another planet in our solar system. And that’s a big deal, really. Since it’s still working, it would make sense for us to keep funding, because as long as it runs the cheaper it gets for us to afford the price of us paying for it and putting it up there.

Fortunately there are the expenditures to study two astronauts that are twins.

Scott and Mark Kelly, the only twins in the astronaut program for NASA, have both been in space before. And Scott is about to go back into space next year; he’ll be the first astronaut to spend an entire year on board International Space Station. So what NASA has done is to put out a request for proposals from ten different institutions for a 1.5 million dollar (each) study of the effects of space on twins. So Mark will stay on Earth, Scott will go into space for a year. They’ll do pre-testing, testing during the flight and post testing to see if they can identify specific differences between astronauts or between bodies — one in space and one on Earth. With the twins being perfect copies, they might be able to discover something significant that can help us overcome some of the difficulties of humans in space.

And perhaps even applications for those of us living on Earth.

Well that’s something that always comes out of these studies of astronauts that happen. And the reason why is because if you consider that the astronaut is the experiment, then someone on the ground — any person — would be the control. So whatever you can observe between the two might be the basis to create something that can benefit medicine here on Earth. So there’s always the space application and almost always an Earth application that grows out of it.

  • Twin astronaut study

    This undated photo provided by NASA, astronauts Mark Kelly, right, STS-124 commander, and Scott Kelly are pictured in the check-out facility at Ellington Field near NASA’s Johnson Space Center in Houston. NASA announced Friday, March 7, 2014, that Mark Kelly and astronaut Scott Kelly will participate in 10 different investigations. Craig Kundrot, deputy chief scientist of NASA’s Human Research Program, says in a news release that the brothers provide a unique opportunity to study two people with the same genetics who were in different environments. Officials say Scott Kelly spent a year in space while Mark Kelly was on Earth. NASA says it is hoping the studies can be the basis for future research initiatives. (AP Photo/NASA)



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