QUESTIONS: Comet 209P/LINEAR

many different sources | Feb 27, 2014 | Yosemitest

[ForGod'sSake]

Interpreting Carolina Bays as Glacier Ice impacts Antonio Zamora

Best piece I've seen yet laying out the mechanism that may have, and IMHO likely did, form the bays.

[Yosemitest]

Please take a look at Will Comet 209P/LINEAR Generate the Next Meteor Storm? figure 2 and figure 3, on page 5 of that .pdf.
This is where some people get the 2.1 Million Miles of debris field that Earth will travel through over 30 hours.

" Figure 2. The footprint of the meteoroid stream from 209P/LINEAR projected on the ecliptic.
The colour scheme labels the free space (no gravitational focusing) fluence of particles through a plane perpendicular to the stream’s arrival direction.
Locations of the Earth at particular times are labeled with arrows.
The Sun is to the upper right. "

Also, if you would take a look at page 6 at figure 4, and read or scan, from pages 4 through 6, the topics "6 DISCUSSION" and "7 SUMMARY"
and tell me if you think that it suggest the chances of larger meteors in the tail are greater than normal.
Figure 1 on page 3 might be worth your time, and may be the image that shows more detail about the comets coma density than others.
I just wish it was larger.

[Yosemitest]

P.S. Can you copy and post those images from that .pdf file onto this thread ?

[Yosemitest]

I don’t know much about the subject, but it looks very well researched and footnoted, to me.

[Yosemitest]

Since the JPL Small-Body Database Browser 1819 Laputa (1948 PC) doesn't come close to Earth, I assume you're talking about this Laputa.

and I agree.

[glock rocks]

bkmk

[Errant]

I understand what you're suggesting but read Mikhail Maslov's Introducton to meteor activity forecasting.

I'm not too sure how well his model theory would apply in this case, since this is more or less a debris field similar to what remains of ISON.

[Robert A Cook PE]

Interesting idea.

Rotate your oblique impact crater and spall pattern slightly counterclockwise - so that the impact crater is a little in line with the Michigan peninsula. As if the Michigan peninsula is the “rebound” or central raised area sometimes (not always!) seen within the impact crater walls themselves/.

Sudberry nickel deposits next door? Another impact?

[Errant]

Comet Linear's Giant Debris Field/NEW IMAGES

[Yosemitest]

His forecasting takes into consideration the particles' size and how they get separated into different parts of the trailing tail.
The solar winds, or as he calls them "non-gravitational forces" or "radiation pressure" have little effect on those particles.

But it's only a model.
And he admits, "but as before, for their improvement, new observations are very necessary. "

[Yosemitest]

From 2 minutes and 6 seconds through the end of that video, is well worth your time.

Comet 209P/Linear is parallel to Earth's orbital plane around May 19 through May 20, 2014,

and we enter that debris trail May 23 through May 25, 2013, for 30 hours, with the peak density forecasted May 24, 2014 at the 7th hour Universal Time,
which should be 1 am Central Daylight Savings TIme.

3 Hours, 52 minutes, and 50 seconds of debris we'll be traveling through, with the center of the peak at 7:21 UT would mean

we would enter the dark area at 11:25 pm Central Daylight Time, May 23, 2014,
and come out of the dark area at 3:17 am Central Daylight Time, May 24, 2014.

But my question now is :

Isn't most of that comet's debris trail moving with the Comet?
If so, then, wouldn't most of the danger be out of the way ?
Wouldn't Comet 209P/Linear ONLY be a threat of major proportion IF
the comet reached the parallel to the orbital plane crossing, directly between Earth and the Sun,
at the exact time the Earth was directly behind it in relationship to the Sun?

Or, is there that much debris left behind from all the orbits Comet 209P/Linear has made before now?

But if that were true, wouldn't we have already experienced some of its meteorite shower during previous passes through its' orbital trails?

[Yosemitest]

Can you tell me how to read figure 4 on page 6 of this .pdf ?
I want to know the sizes of those particles in real numbers.
I'm guessing the "radius (m)" is meters.
But I don't understand "log10(radius(m)" or "All Weighted: Ten bins per decade of radius(m)"

[Errant]

From the International Meteor Organization (IMO):

"Possible meteor activity due to Comet 209P/LINEAR: Of greatest potential significance this quarter, indeed this year, is an encounter between the Earth and a number of dust trails left by Comet 209P/LINEAR at its perihelion returns within twenty years to either side of 1900 AD. Several predictions have already been issued for what may occur, and further updates are likely nearer the event. Based on the most recent independent calculations by Esko Lyytinen, Mikhail Maslov and J´er´emie Vaubaillon, the strongest activity from this source should happen on May 24, most likely between about 07h to 08h UT from a radiant near the borders of Lynx, Ursa Major and Camelopardalis, quite close to o UMa. The predicted radiant locations fall within a few degrees of α = 124° , δ = +79° . Timings in UT for the centre of the strongest activity overall are around 07h 03m (Lyytinen), 07h 21m (Maslov) and 07h 40m (Vaubaillon) respectively. However, much is unknown about this comet, including its dust productivity and even its precise orbit. Consequently, while tentative proposals have been made that ZHRs at best could reach 100+, perhaps up to storm proportions, based purely on the relative approach distances between the Earth and the computed dust trails, these are far from certain. The strongest activity could be short lived too, lasting perhaps between a few minutes to a fraction of an hour only. In addition, the number of dust trails involved means there may be more than one peak, and that others could happen outside the “key hour” period, so observers at suitable locations are urged to be vigilant for as long as possible to either side of the predicted event to record whatever takes place. Remember, there are no guarantees in meteor astronomy! Lunar observing circumstances are very positive, with May’s new Moon on the 28th. The north-circumpolar radiant area for many sites means the three main geographic zones where most radio observers are located – Europe, North America and Japan – should be able to follow all that occurs, interference permitting. The time of year means the northern nights are close to their shortest for visual and imaging work, but the predicted strongest activity timings fall perfectly for night-time coverage all across North America and the nearby oceans to its east and west. See WGN and watch out for online news closer to the event for additional information."

http://www.imo.net/calendar/2014

No expert here by any means. I'm just looking at the satellite images from the youtube vids and seeing the large still visible but extended debris left over from what at one time must been a single body comet. As the piece above says, there are a lot of unknowns. One unknown: will the slight coma/tail brighten more? If it does that will more 'dust' is being generated and blown away giving us a chance of a better light show in the night sky.

This isn't a danger to earth due to the small size of the particles. What is, is if any large size 'stragglers' from the main debris field impacts the earth. The odds of that increase due to a relative close approach of the main debris field itself to earth and because it is a field of debris and not a single body.

It would only take one of those pieces of the original comet of significant size impacting a populated area to create major havoc. It's pretty obvious a debris field is what we're seeing on the satellite images. It seems the composition, size of the field, and layout is either unknown or not being released. I'm not sure why it seems NASA likes to sit on the data nowadays. They were really forthcoming with info on a asteroid that missed earth by half the distance to the sun recently

Artist rendering of an asteroid field:

On May 29, 2014, the comet will pass 0.0554 AU (8,290,000 km; 5,150,000 mi) from the Earth (https://en.wikipedia.org/wiki/209P/LINEAR

That will be the main body of debris, passing ahead of and after dropping below the earth's orbit, with the earth actually passing through the trailing dust trail a few days before. The question I have is just how far back/out from the main body, are pieces of significant size?

Another update from Jessie: Linear Debris Update. Unbelievable Charts.

[Errant]

Can you tell me how to read figure 4 on page 6 of this .pdf?

Sorry but no. I don't know what they mean by ""All Weighted: Ten bins per decade of radius(m)" either... lol

What their model deals with is an estimated amount and size of small grains of 'dust' from a comet's nucleus, forming a trail affected by solar wind and gravity. What it doesn't appear to deal with (at least I have not seen where it attempts to) is larger debris from jetting, spin inertia, tidal force, or long term CME/Solar 'wind' effects from a comet that has 'broken up'.

[Errant]

Ooops, I was meaning to say above: NASA was forthcoming with data on the asteroid that recently missed the earth by half the distance of this comet's closest approach.

To be more precise, that asteroid was about 300' in diameter and missed earth by 3M miles on the 17th Feb., IIRC. This comet will pass about 5M miles and is a whole lot larger I believe.

[Yosemitest]

I didn't know his real name. Thanks.
That video's data charts are here.

" The Earth is expected to encounter a great numbet of the comet 209P trails in 2014.
The main source of activity should become 1898-1919 trails,
however some meteors could be produced by the earlier trails of the comet, down to 1763 trail,
which is the oldest computed trail, and even earlier.
The computed time of maximum acitivity is May 24, 2014, at 7:21 UT, theoretical radiant is RA=122.8�, Dec=+79.0�.
It is difficult to estimate expected intensity of the outburst
due to the lack of past observed cases of activity from the given comet meteor shower,
as well as due to very small size of the comet itself
and unknown level of its past activity.
However, considering high computed density and high number of encountered trails,
we can very approximately estimate ZHRex as 100 meteors.
Its a very cautious estimation, and it is very possible that real acitivity will turn to be much higher.
Storm levels are also far from being excluded. "

Reference your comment: "On May 29, 2014, the comet will pass 0.0554 AU (8,290,000 km; 5,150,000 mi) from the Earth ..."

John Bochanski's article from November 12, 2013 stated;

" Detailed calculations of its orbit indicated that in May 2014 the comet’s debris trails would pass extremely close to Earth
(about 0.0002 Earth-Sun distances, ...). "

I'll assume that he was talking about the center of the Comet 209/Linear's core's path.

I run the math on that and

IF an astronomical unit is defined as the average distance from the Sun to the Earth, or about 93 million miles (150 million kilometers),
THEN 0.0002 AU is about 18,600 miles.

That 's a lot closer than 5,150,000 miles from Earth.
Also, it's not the closeness to Earth itself, but the closeness to Earth's orbital plane within just a few days.

What we NEED TO KNOW ~ IS :

the distance Comet 209P/Linear will be from Earth's Orbital Plane on May 19-20, 2014,
as it goes from above-to-below Earth's Orbital Plane.

[Yosemitest]

Based on the "Figure 4" chart on page 6 of the .pdf from Quanzhi Ye⋆ and Paul A. Wiegert, and a great amount of reading of "how to interpret the data", (I could be WRONG)

IF I read that figure 4 chart correctly,
then the "mean" particle size is between 7 inches to 8 inches in size,
and the "mode" particle size is between 10.5 inches and 11.5 inches in size.
Here's how I took an "educated GUESS" at it.
From the .pdf
" ...From these data we conclude that the Afρ of 209P/LINEAR stays at 1 cm ( 0.3937007874 inch) level throughout its perihelion passage.

Assuming a meteoroid density of ρ = 300 kg·m−3 and a particle radius r measured in meters, the ratio of solar radiation pressure to gravity β is given by β = 5.74 × 10−4/ρr in these units following Fox et al. (1982); Williams & Fox (1983). This yields a particle size of ∼ 0.6 mm ( 0.2362 inch ), which indicates a predominance of large particles.

In the absence of other details, we assume a Bond albedo for the nucleus of 0.05, which yields a nucleus size of 600 m ( 1,968.48 feet); we also assume a nucleus density of 300 kg · m−3.

We first integrate the orbit of 209P/LINEAR backwards 250 years. The comet is then integrated forward again, with particles released at each perihelion passage.

Though the number of particles arriving at Earth is relatively small, the size distribution is skewed strongly towards larger particles (Figure 4). Despite the relative rarity of large particles in the simulation (due to a size distribution which favors smaller ones), meteoroids arriving at Earth are predominately larger than 1 mm ( 0.3937007874 inch). Given that our syndyne calculations indicate that the parent produces particles most abundantly at the size which are most efficiently delivered to Earth in our simulations, it may be that the shower will prove unusual for the number of bright meteors produced.

SUMMARY
We reanalyzed the optical observations made during the 2009 apparition of 209P/LINEAR to constraint the dust production activity of the comet,
in the hope to verify and refine the prediction of the forthcoming meteor outburst in 2014 as caused by this comet.
Our analysis showed that 209P/LINEAR is considerably depleted in dust production, with Afρ ≈ 1 cm ( 0.3937007874 inch) within eight months around its perihelion,
which indicated the comet may be currently transitioning from typical comet to a dormant comet.
By fitting the observation to syndyne model, we found that the tail is dominated by larger particles.

Our numerical simulation confirmed the arrival of particles from some of the 1798–1979 cometary trails from 209P/LINEAR on 2014 May 24.
The peak of the meteor activity is expected at 2014 May 24, 6h29m UT, with FWHM about 0.4 days.

However, our simulation showed that the size selection is skewed strongly to larger particles; considering that the syndyne simulation indicated that the tail of 209P/LINEAR is dominated by larger particles,
we suggested that the meteor outburst, if detectable, may be dominated by bright meteors.

My "educated GUESS" at converting the "Figure 4" chart Logarithm numbers:

log10 (radius(-1.0)) = 0.1
IF nucleus size radius is 984.24 feet (1,968.48 feet divided by 2)
98.424 feet particle size

log10 (radius(-1.5)) = 0.05
49.212 feet

log10 (radius(-2.0)) = 0.01
9.8424 feet

log10 (radius(-2.5)) = 0.005
4.9212 feet

log10 (radius(-3.0)) = 0.001
0.98424 feet or 11.81088 inches

log10 (radius(-3.5)) = 0.0005
0.49212 feet or 5.90544 inches

log10 (radius(-4.0)) = 0.0001
0.098424 feet or 1.181088 inches

log10 (radius(-4.5)) = 0.00005
0.049212 feet or 0.590544 inch

log10 (radius(-5.0)) = 0.00001
0.0098212 or 0.1181088 inch

You really should view the "Figure 4" chart on page 6 of the .pdf ~ for yourself.

[Errant]

What we NEED TO KNOW ~ IS :the distance Comet 209P/Linear will be from Earth's Orbital Plane on May 19-20, 2014,as it goes from above-to-below Earth's Orbital Plane.

Check JPL's small body simulator - if you can get it to work as I'm getting java errors recently. If you can get it working, it'll give you those numbers.

A cursory look at your size calculations leads me to believe there is something wrong. Perhaps 'm' stands for micron (was that a big M or a little m? :-) Those are objects you have there - not particles... ;)

No doubt if you hang with it, you'll figure out the numbers and I complement you for your work!

[Yosemitest]

The distance of Comet 209P/Linear's orbit to where the Surface of Earth WILL BE in its orbital plane on May 24, 2014 at 00:00:00 ~ is

from 863,222.98 miles to 863,243.98 miles on the nearest side,
and from 871,116.98 miles to 871,158.98 miles to the opposite side of Earth's orbital plane.

Those numbers decrease my concern level considerably from the "about 18,600 miles" that I commented on in comment #56.
That's a lot further out than John Bochanski's article stating

" Detailed calculations of its orbit indicated that in May 2014 the comet’s debris trails would pass extremely close to Earth(about 0.0002 Earth-Sun distances, ...). "

which figured to be about 18,600 miles.

I didn't get it from JPL's models, but I run Stellarium 0.12.4 for Earth's distance from the Sun on May 24, 2014 at 00:00:00 Central Daylight Savings Time as 1.00571510 AU .
It showed Comet 209P/Linear distance from the Sun as it is on the same laditude of Earth's Orbital Plane on May 20, 2014 at 00:00:00 Central Daylight Savings Time, is 0.99639024 AU.

1.00571510 AU minus
0.99639024 AU equals
0.00932486 AU times (Earth is a distance of 0.36184615 AU from Comet Linear at that time)
93,000,000 miles equals
867,211.98 miles from Earth's Orbital Plane
minus the radius of Earth ( 3,947–3,968 mi )

[Yosemitest]

" Perhaps 'm' stands for micron (was that a big M or a little m? :-) "

The only thing in his paper that addressed it was above the Figure 3 and Figure 4 charts where it stated

"Size Range (m)"

It stated below Figure 4

"log10(rsdius (m))"

So I used the Logarithm numbers above that statement at the bottom of that chart,

ranging from "-5.0" through "-1.0",

to figure the sizes from their stated model radius size of Comet 209P/Linear.