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.
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
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.
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
Such a wonderful puzzle.
I hope Lucy has more for us.