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Readers!

 

My July fund-raising campaign to celebrate the fifteenth anniversary since I began Behind the Black is now over. I want to thank all those who so generously donated or subscribed, especially those who have become regular supporters. I can't do this without your help. I also find it increasingly hard to express how much your support means to me. God bless you all!

 

The donations during this year's campaign were sadly less than previous years, but for this I blame myself. I am tired of begging for money, and so I put up the campaign announcement at the start of the month but had no desire to update it weekly to encourage more donations, as I have done in past years. This lack of begging likely contributed to the drop in donations.

 

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Third star destroying part of expanding shells surrounding binary Wolf-Rayet stars

Apep system.
From figure 3 of the paper.

Using the Webb Space Telescope, astronomers think they can now disentangle the strange spiral shape of the expanding dust shells caused by the colliding powerful winds flowing from a binary pair of giant aging Wolf-Rayet stars, dubbed the Apep system.

Apparently, a third smaller O-type star sits in the system, and is acting to block the winds and destroy the dust within them, carving out a large cavity in the spiral shells. The image to the right, produced by the Very Large Telescope in Chile, shows the spiral dust shells shaped by the strong solar winds flowing and colliding from the binary Wolf-Rayet stars (the bright dot in the center). The O-type star can be seen just above them. The yellow lines indicate the empty cone. Without the O star computer models had predicted a very bright shell north of the binary, and its non-existence in VLT images caused these further Webb observations.

From the paper’s [pdf] conclusion:

The JWST observations of Apep reveal luminous circumstellar dust that support[s] … our finding that the O supergiant ‘northern companion’ is dynamically associated with the binary WR stars in Apep; this is the first time that dust destruction has been observed by a tertiary star in a colliding wind nebula, and marks Apep as part of a rare class of triple colliding wind binaries.

The dust produced by Wolf-Rayet stars is thought to be a major component in seeding the formation of later stars, such as our own Sun. Finding that a third star in the system can destroy that dust suggests (as always) that this process can be far more complicated that first believed.

Hat tip to BtB’s stringer Jay.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

 

The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.


The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
 

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News

2 comments

  • Ben K

    Apparently finding a binary system with 2 W-R stars is quite rare, so this is a good opportunity for further study even without considering the companion O type.

  • Max

    Fascinating and aesthetically beautiful.
    As a modern Ying yang symbol, it would look great on a T-shirt.

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