Scientists propose three scenarios for the creation of Dinkinesh’s contact-binary moon Selam
Click for original graphic.
Click for original image.
Scientists have now used the data obtained during Lucy’s close fly-by of the asteroid Dinkinesh in November 2023 to propose three scenarios to explain the existence of its contact-binary moon Selam, as well as the trough and equatorial ridge on Dinkinesh.
The image to the right shows Selam to the right of Dinkenesh. The graphic above shows the three scenarios proposed for Selam’s creation. This is figure 4 from the paper published today. From the caption:
Asteroids with diameters less than approximately 10 km are subject to spin-up by the YORP effect [changes to rotation and motion due to solar radiation impacting the asteroid’s surface]. Rapid spin of the primary and the associated centrifugal force eventually trigger a structural failure that leads to sudden mass shedding. This event might also have created the trough seen on Dinkinesh through the mass movement of a portion of the body. The shed material forms a ring, with some material coalescing into a satellite(s) and closer material eventually falling back to the surface at the equator to form the ridge. The formation of the contact binary may be the result of a merger of two satellites formed either in a single mass-shedding event (a) or in two separate events (b). An alternative scenario (c) is that Selam formed as a single object that subsequently underwent fission owing to spin–orbit coupling.
Of course, none of this is confirmed, though these hypotheses fit the available facts.
Lucy is presently heading to a fly-by of Earth in December 2024. It will then zip past another main belt asteroid in April 2025 before arriving in August 2027 among the Trojan asteroids in Jupter’s orbit. Once there it will visit at least eight different asteroids.
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Click for original graphic.
Click for original image.
Scientists have now used the data obtained during Lucy’s close fly-by of the asteroid Dinkinesh in November 2023 to propose three scenarios to explain the existence of its contact-binary moon Selam, as well as the trough and equatorial ridge on Dinkinesh.
The image to the right shows Selam to the right of Dinkenesh. The graphic above shows the three scenarios proposed for Selam’s creation. This is figure 4 from the paper published today. From the caption:
Asteroids with diameters less than approximately 10 km are subject to spin-up by the YORP effect [changes to rotation and motion due to solar radiation impacting the asteroid’s surface]. Rapid spin of the primary and the associated centrifugal force eventually trigger a structural failure that leads to sudden mass shedding. This event might also have created the trough seen on Dinkinesh through the mass movement of a portion of the body. The shed material forms a ring, with some material coalescing into a satellite(s) and closer material eventually falling back to the surface at the equator to form the ridge. The formation of the contact binary may be the result of a merger of two satellites formed either in a single mass-shedding event (a) or in two separate events (b). An alternative scenario (c) is that Selam formed as a single object that subsequently underwent fission owing to spin–orbit coupling.
Of course, none of this is confirmed, though these hypotheses fit the available facts.
Lucy is presently heading to a fly-by of Earth in December 2024. It will then zip past another main belt asteroid in April 2025 before arriving in August 2027 among the Trojan asteroids in Jupter’s orbit. Once there it will visit at least eight different asteroids.
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. IMPORTANT! If you donate enough to get a book, please email me separately to tell me which book you want and the address to mail it to.
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.
Such a wonderful puzzle.
I hope Lucy has more for us.