Betelgeuse is closer and smaller than previously thought
![Betelgeuse's fading](https://behindtheblack.com/wp-content/uploads/2021/02/202012-nmt-fig1Ecropped.jpg)
Images taken by Europe’s
Very Large Telescope in Chile
The uncertainty of science: A new analysis by scientists of Betelgeuse, triggered by its dip in brightness in 2020, has concluded that the red giant star is both closer and smaller than previously estimated.
Their analysis reported a present-day mass of 16.5 to 19 solar mass—which is slightly lower than the most recent estimates. The study also revealed how big Betelgeuse is, as well as its distance from Earth. The star’s actual size has been a bit of a mystery: earlier studies, for instance, suggested it could be bigger than the orbit of Jupiter. However, the team’s results showed Betelgeuse only extends out to two-thirds of that, with a radius 750 times the radius of the sun. Once the physical size of the star is known, it will be possible to determine its distance from Earth. Thus far, the team’s results show it is a mere 530 light years from us, or 25 percent closer than previously thought.
The research also suggested that the star is in the initial stages of burning helium rather than hydrogen, and so it likely more than 100,000 years from going supernova.
As for the dimming, the scientists concluded (as other have) that the dimming in ’20 was due to the passage of a dust cloud in front of the star.
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Images taken by Europe’s
Very Large Telescope in Chile
The uncertainty of science: A new analysis by scientists of Betelgeuse, triggered by its dip in brightness in 2020, has concluded that the red giant star is both closer and smaller than previously estimated.
Their analysis reported a present-day mass of 16.5 to 19 solar mass—which is slightly lower than the most recent estimates. The study also revealed how big Betelgeuse is, as well as its distance from Earth. The star’s actual size has been a bit of a mystery: earlier studies, for instance, suggested it could be bigger than the orbit of Jupiter. However, the team’s results showed Betelgeuse only extends out to two-thirds of that, with a radius 750 times the radius of the sun. Once the physical size of the star is known, it will be possible to determine its distance from Earth. Thus far, the team’s results show it is a mere 530 light years from us, or 25 percent closer than previously thought.
The research also suggested that the star is in the initial stages of burning helium rather than hydrogen, and so it likely more than 100,000 years from going supernova.
As for the dimming, the scientists concluded (as other have) that the dimming in ’20 was due to the passage of a dust cloud in front of the star.
Readers!
Every February I run a fund-raising drive during my birthday month. This year I celebrate my 72nd birthday, and hope and plan to continue writing and posting on Behind the Black for as long as I am able.
I hope my readers will support this effort. As I did in my November fund-raising drive, I am offering autographed copies of my books for large donations. Donate $250 and you can have a choice of the hardback of either Genesis: the Story of Apollo 8 or Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space. Donate $200 and you can get an autographed paperback copy of either.
Please consider supporting my work here at Behind the Black. My analysis of space, politics, and culture, taken from the perspective of an historian, is almost always on the money and ahead of the game. For example, in 2020 I correctly predicted that the COVID panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Every one of those 2020 conclusions has turned out right.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
Robert related: “The research also suggested that the star is in the initial stages of burning helium rather than hydrogen, and so it likely more than 100,000 years from going supernova.”
That seems like an incredibly short time for things that hang around for billions of years. While I am aware of the main sequence fuel cycle, I had no idea it happened on that sort of timescale. I am sure there are many on the forum who can shed some light.
Betelgeuse is too bright for the Gaia space telescope. So I don’t think it is known how it moves, whether it will be closer or further away from the Sun in 100,000 years. Its variability (huge sunspots and flares) also makes it tricky to pinpoint its distance and radial movement. Only 10 or so years ago, tables had it at only 470 light years distance, then they almost doubled the estimation, and now 530 ly.
@Blair K Ivey
Betelgeuse is only 8 million years old. More massive stars have higher pressure from gravity and burn their fuel much faster, a larger core is fusing. Betelgeuse is only about 18 times as massive as the Sun, there are stars 100+ the mass of the Sun that exist for less than a million years. That’s why more massive stars are much less frequent, they don’t necessarily form more rarely, they just live 1/1000th or so as long as stars less massive than the Sun. Still, the spirals in galaxies are visible because of the small share of massive stars that dominate the brightness of 100s-1000s of times more common red dwarfs and Sun-like stars. Galactic gas is compressed in a standing spiral wave so that stars form much more easily there. And the massive stars don’t live long enough to leave the spiral where they formed.
Blair–
can’t find the chart I want, but when a star starts ratchetting up the periodic table toward iron, the end is ‘relatively near.’
…” it takes 100,000 years for the carbon to burn into oxygen, 10,000 years for the oxygen to burn into silicon, and one day for the silicon to burn into iron… “
“Stages in the Life of a 25 Solar Mass Star”
-hydrogen burning – 7 million years
helium – 700K years
cabon – 600 years
neon – 1 year
oxygen – 6 months
silicon – 1 day
http://hosting.astro.cornell.edu/academics/courses/astro201/highmass.htm
@wayne
It takes on average 10,000 years for a photon generated in the fusing core of the Sun to reach the surface and beam out through space. There’s so much compact stuff in the way of its 400,000 miles random walk. In your example, virtually no light from the post Helium fusion would become visible until it goes supernova.