Twin Fireballs may have come from 103P/Hartley 2.

[3488]

Very interesting article on the front page.

Astronomers have recorded two magnificent fireballs that may have come from a nearby comet that made its closest pass by Earth in 24 years this month, prompting speculation on whether the icy cosmic visitor may be offering a meteor shower show.

The fireballs were spotted on Oct. 16, just four days before of the close pass by Comet Hartley 2 and a few weeks ahead of a Nov. 4 visit to the comet by a NASA spacecraft. It is possible the fireballs are related to the co.....

Tariq Malik. Space.Com.

Twin Fireballs may have come from 103P/Hartley 2.

Andrew Brown.

 

[orionrider]

Thank you Andrew.

Would that mean the comet is coming apart from tidal forces? Hartley 2 hasn't been much of a backyard show. Apart form it's amazing apparent velocity if was quite faint and unremarkable.

Also the fact that the fragments travel ahead of the comet is puzzling. You would expect fragments dislodged from a comet to be pushed by the solar wind in the direction of the tail. :?

 

[MeteorWayne]

I'll have to wait a while for more analysis before making up my mind about this. Intriguing if true. Let's see what EPOXI shows us

As for meteoroids being ahead of the comet, don't forget the comet orbits every 6 years and has made dozens of circuits since it entered the closer to earth orbit. Particles are ejected each time.

Halley's comet orbits in about 86 years, yet we get 2 meteor showers every year from it. Swift-Tuttle 133 years, yet we get Perseids every year, which last 7 weeks. Tempel-Tuttle 33 years; Leonids every year.

The point is that once the particles are ejected, they each follow their own orbit. Close to their ejection point (~ 1 AU) they are close together, but after that they are spread out all over which makes their orbital period much different.

If a particle is ejected in the direction the comet is moving, it's speed is higher, which makes the orbit larger and the period longer. If it's ejected backwards, the speed is slower, the orbit smaller, and the period shorter.

 

[MeteorWayne]

There have been unconfirmed reports of more possible fireballs. If you'd like to look, the actual radiant would be about halfway between eta-Cygni and Albiero. Albiero is the very nice double star at the head of Cygnus the Swan, eta-Cyg is the one about halfway from there to where the wings cross the body. Due to the very slow velocity of the meteors, the meteors would appear to come from a point closer to where the wings cross, about 10 degrees (a fist width held at arms length) higher. They would be some of the slowest meteors you can see.

The best time would be just after sunset (sorry kids, northern hemisphere only) when the radiant is overhead; it sets by about 2 AM.

MW

 

[orionrider]

They would be some of the slowest meteors you can see.

MW, what would be the relative velocity of the fragments on reentry?

 

[MeteorWayne]

They would hit the atmosphere at ~16 km/sec (compared with say 60 km/sec for the Perseids) and would decelerate as they ablate and vaporize away. At the end, there's nothing left but gas and minute dust particles.

(Based on 12 km/s approach speed and 11 km/sec acceleration from earth's gravity)

MW

 

[nailpounder]

If you'd like to look, the actual radiant would be about halfway between eta-Cygni and Albiero. Albiero is the very nice double star at the head of Cygnus the Swan, eta-Cyg is the one about halfway from there to where the wings cross the body. Due to the very slow velocity of the meteors, the meteors would appear to come from a point closer to where the wings cross, about 10 degrees (a fist width held at arms length) higher. They would be some of the slowest meteors you can see.

MW, between the 15th and 18th of October, I caught 3 of the SLOWEST meteors I have EVER seen. Although NOT originating from Cygnus, they were seen just south of Scheat and Markab in Perseus, more going right through
Iota Pegasus and down towards Homan. Could these possibly be remnants of 103P/Hartley? Sightings were between 8-9 pm. My location is 34.272973, -119.175872

OOPS, Scheat and Markab are in Pegasus, not Perseus as I stated..............al

 

[orionrider]

Thank you MW, very interesting stuff!

 

[MeteorWayne]

If you'd like to look, the actual radiant would be about halfway between eta-Cygni and Albiero. Albiero is the very nice double star at the head of Cygnus the Swan, eta-Cyg is the one about halfway from there to where the wings cross the body. Due to the very slow velocity of the meteors, the meteors would appear to come from a point closer to where the wings cross, about 10 degrees (a fist width held at arms length) higher. They would be some of the slowest meteors you can see.

MW, between the 15th and 18th of October, I caught 3 of the SLOWEST meteors I have EVER seen. Although NOT originating from Cygnus, they were seen just south of Scheat and Markab in Perseus, more going right through
Iota Pegasus and down towards Homan. Could these possibly be remnants of 103P/Hartley? Sightings were between 8-9 pm. My location is 34.272973, -119.175872

You'll have to give me a little time. I ain't very good with star names

I know where all the stars are, and the visual magnitude of them, but didn't have much memory available for tons of star names. I know the biggies, maybe 3 dozen most of the time, and another dozen or so in my current meteor observing field of view during the seasons, so I'll have to look up which are which.

Then I'll check the radiants for the date. The Draconid shower also has exceptionally slow meteors and would be well placed in the evening, though would not be expected to be active that late in the month. Then there's 2 or 3 other super minor showers I need to check out....

Oh, and BTW, if a meteor's path started in Cygnus on the dates above, it would likely not be from the described radiant. The general rule is that the radiant lies along the backwards projection of the path, no closer than a distance at least that of the meteor path.

It's a 3D physics thing

MW

 

[nailpounder]

If you'd like to look, the actual radiant would be about halfway between eta-Cygni and Albiero. Albiero is the very nice double star at the head of Cygnus the Swan, eta-
You'll have to give me a little time. I ain't very good with star names

I know where all the stars are, and the visual magnitude of them, but didn't have much memory available for tons of star names. I know the biggies, maybe 3 dozen most of the time, and another dozen or so in my current meteor observing field of view during the seasons, so I'll have to look up which are which.

Then I'll check the radiants for the date. The Draconid shower also has exceptionally slow meteors and would be well placed in the evening, though would not be expected to be active that late in the month. Then there's 2 or 3 other super minor showers I need to check out....

Oh, and BTW, if a meteor's path started in Cygnus on the dates above, it would likely not be from the described radiant. The general rule is that the radiant lies along the backwards projection of the path, no closer than a distance at least that of the meteor path.

It's a 3D physics thing

MW

I screwed that up anyway. I meant Pegasus, not Perseus. To make it easier, these were viewed just to the right of
"the box" that makes up Andromeda and Pegasus. It's been a great month for meteors. I've seen 30 or more in the
last 3 weeks. But as I said only three really caught my attention as they just appeared to move about 1/3 the speed
of an average one. We've had some great skies due to high pressure here on the Cal. coast.......al

 

[MeteorWayne]

Well, this is the peak of activity for the N & S Taurids, which produce slow meteors, and in some years numerous fireballs over a 2 month period.

 

[orienteer]

Okay, we have now seen the nucleus of Hartley. Any idea where the twin fireballs may have been attached? does the comet continuously stretch apart until a piece finally 'drips' off? Would that explain the smooth waist?

 

[MeteorWayne]

The fireballs were objects maybe a few cm in diameter. Such sized objects are ejected from comets all the time by the jets.

And the case of the 2 fireballs being related to Hartley 2 has only been suggested, not proven.