by Eclectic Man » Wed Jan 12, 2022 10:30 pm
Chris Peterson wrote: ↑Wed Jan 12, 2022 2:02 pm
orin stepanek wrote: ↑Wed Jan 12, 2022 12:35 pm
When a comet can no longer produce a tail; does it become an asteroid?
The terminology isn't rigorously defined. In common usage, an asteroid is any rocky body above a certain size but not meeting the definition of a planet. There are almost certainly bodies we identify as asteroids that started out as comets. But if there's a good reason to think a rocky body that is devoid of volatiles started out as a comet, we're inclined to refer to it as an extinct comet (or some similar terminology). The distinction can be important given the presumably different history of formation and evolution of comets and asteroids.
Asteroid 248370 appears to also be a comet:
http://www.sci-news.com/astronomy/main- ... 10137.html
"(248370) 2005 QN137 is the eighth main-belt asteroid, out of more than half a million asteroids in the main belt, confirmed to not only be active, but to have been active on more than one occasion.
248370) 2005 QN173 was discovered to be active on July 7, 2021 in data obtained by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) survey telescope.
On that date, the object was at a heliocentric distance of 2.39 AU (astronomical units), and exhibited a thin, straight dust tail.
“This behavior strongly indicates that its activity is due to the sublimation of icy material,” said Dr. Henry Hsieh, senior scientist at the Planetary Science Institute.
“As such, it is considered a so-called main-belt comet, and is one of just about 20 objects that have currently been confirmed or are suspected to be main-belt comets, including some that have only been observed to be active once so far.”
“2005 QN173 can be thought of as both an asteroid and a comet, or more specifically, a main-belt asteroid that has just recently been recognized to also be a comet.”
"
[quote="Chris Peterson" post_id=319839 time=1641996133 user_id=117706]
[quote="orin stepanek" post_id=319836 time=1641990914 user_id=100812]
When a comet can no longer produce a tail; does it become an asteroid?
[/quote]
The terminology isn't rigorously defined. In common usage, an asteroid is any rocky body above a certain size but not meeting the definition of a planet. There are almost certainly bodies we identify as asteroids that started out as comets. But if there's a good reason to think a rocky body that is devoid of volatiles started out as a comet, we're inclined to refer to it as an extinct comet (or some similar terminology). The distinction can be important given the presumably different history of formation and evolution of comets and asteroids.
[/quote]
Asteroid 248370 appears to also be a comet:
http://www.sci-news.com/astronomy/main-belt-comet-10137.html
"(248370) 2005 QN137 is the eighth main-belt asteroid, out of more than half a million asteroids in the main belt, confirmed to not only be active, but to have been active on more than one occasion.
248370) 2005 QN173 was discovered to be active on July 7, 2021 in data obtained by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) survey telescope.
On that date, the object was at a heliocentric distance of 2.39 AU (astronomical units), and exhibited a thin, straight dust tail.
“This behavior strongly indicates that its activity is due to the sublimation of icy material,” said Dr. Henry Hsieh, senior scientist at the Planetary Science Institute.
“As such, it is considered a so-called main-belt comet, and is one of just about 20 objects that have currently been confirmed or are suspected to be main-belt comets, including some that have only been observed to be active once so far.”
“2005 QN173 can be thought of as both an asteroid and a comet, or more specifically, a main-belt asteroid that has just recently been recognized to also be a comet.”
"