Starship Asterisk*

Ann wrote:Interesting. Asteroids and comets are clearly more alike than previously thought, although one kind of body is wetter than the other.

carsten_nielsen wrote:P/2013 P5 is a comet designation, an asteroid has two letters before the number, f.i. PP5 or GH. The first asteroids are named 2013 PA and PB.

P/ means periodic comet, so it has been identified as one that has been here before

But you maybe should name the APOD Unexpected Tails of Comet P5

Regards

Carsten Nielsen
Denmark

Phil Plait wrote:So in reality, for this object, there’s no real confusion over what it is. It’s an asteroid; it just looks, for now, like a comet. But the resemblance is superficial, caused by two very different processes. What I do find amusing is the name of the object: P/2013 P5 is a comet name. Asteroids have just the year of discovery and a letter/number combination that indicate when in the year it was discovered (and after a while, they’re given names, too). The “P” in P/2013 indicates it’s a periodic comet, which we now know is a misnomer.

As I reported yesterday, a comet was mistaken for an asteroid, and so the name changed from 2013 US10 to C/2013 US10 (Catalina), indicating the reclassification. I wonder if P/2013 P5 will also get a new name? It should.

Well, no matter we decide to call it, P5 is doing whatever it is it should be doing. It’s up to us to figure that out, and not let names get in the way of understanding.

JohnD wrote:Quote "light pressure from the Sun is causing the asteroid to rotate increasingly rapidly, which in turn causes pools of previously gravity-bound dust to spin off"

Wouldn't that cause the tails to spiral, like the 'tails' of a Catherine wheel firework?

John

JohnD wrote:
Quote "light pressure from the Sun is causing the asteroid to rotate increasingly rapidly, which in turn causes pools of previously gravity-bound dust to spin off"

Wouldn't that cause the tails to spiral, like the 'tails' of a Catherine wheel firework?

Rothkko wrote:

http://en.wikipedia.org/wiki/Swastika:

<<Carl Sagan in his book Comet (1985) reproduces Han period Chinese manuscript (the Book of Silk, 2nd century BC) that shows comet tail varieties: most are variations on simple comet tails, but the last shows the comet nucleus with four bent arms extending from it, recalling a swastika. Sagan suggests that in antiquity a comet could have approached so close to Earth that the jets of gas streaming from it, bent by the comet's rotation, became visible, leading to the adoption of the swastika as a symbol across the world.>>

Ron-Astro Pharmacist wrote:Did the HST do (or can it do) a spectra on the light from the ejected material to compare it to other objects of similar nature?

Billsey wrote:Some have recently been postulating that "asteroids" might simply be "comets" that have lost their volatiles. Think about: you get a huge population of comets trapped in orbits that are entirely (or mostly) between the orbits of Jupiter and Mars, and it won't be long (on an astronomical scale) before they lose all their volatiles, leaving only rocky material behind.

DCStone wrote:

JohnD wrote:Quote "light pressure from the Sun is causing the asteroid to rotate increasingly rapidly, which in turn causes pools of previously gravity-bound dust to spin off"

Wouldn't that cause the tails to spiral, like the 'tails' of a Catherine wheel firework?

John

DC,
Only if the jets are constant in direction (relative to the asteroid's body) and intensity. More likely that these are variable in both, so you get a tumbling effect: "Houston, we are venting something into space"

JohnD wrote:
Neufer,

Your first link shows exactly what I mean! Completely different to the recnt APODs, and most relevant.

Your second shows a classic comet tail, driven by solar wind, not by ejection from the object, and so not relevant. IMHO.

Seba wrote:Hey,
Asteroid losing his material exposes more layers of its capacity.
Some rocks, for example: sulfur with friction can burn spectacular!
Our asteroid rotates and leaves tails like below film with fireworks, right?
Two main questions are: tails come from the ignition, or come from explosion? What substance is causing it??
And other questions resulting from this:
If we had a time-lapse sequence of Hubble would be clear .... can anyone have or know?
What is chemical composition of the explosive?
How explosive can be generally asteroids?

By the way, comparing the pictures you can see the difference in volume and shape of six tails (even rotation), or not?
....
thanks in advance for your help and explanations!


Anyway,
The basic composition of the fireworks is:
(...) an oxidant and combustible. Oxidizers are nitrates, chlorates, chromates and sulphates of potassium, barium, strontium, and calcium ammonium. The combustible materials are non-noble metals: magnesium, aluminum and zinc, nonmetals phosphorus, sulfur and carbon, iron sulfide, arsenic, antimony and hydrocarbons and carbohydrates. (...)
And, of course, Dyes and Binder.

deathfleer wrote:off topic.
Mr. Nuefer , etc,
I would be very pleased if you could verify these two photos:-
http://www.akhwatmuslimah.com/wp-conten ... crack1.jpg

and
http://www.akhwatmuslimah.com/wp-conten ... elah-1.jpg

thanks

Seba wrote:Two main questions are: tails come from the ignition, or come from explosion? What substance is causing it?