[meteorite-list] re: Bootids (Quadrantids) meteor shower and 2003 EH1

Mail actions: [ respond to this message ] [ mail a new topic ]
Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:03 2004
Message-ID: <18a.2394c06d.2d195612_at_aol.com>

--part1_18a.2394c06d.2d195612_boundary
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: quoted-printable

Hi Marco,

Thanks for the relevant comments including:

>>Still I do not think this stream is a likely source of meteorites.=20
>>You point to the St. Mark's EH5, and Lost City H5 (which
>>anyhow has an orbit unlike that of 2003 EH1). St. Mark's is=20
>>a chondrite with a rather high petrologic grade (5), i.e. it has=20
>>undergone thermal metamorphism.=A0 Those are not the kind of=20
>>bodies that I would connect with the clearly cometary=20
>>Quadrantid meteoroids.

Regarding St. Marks, first let me say that I believe the current main=20
suspected source of EH5 -thermally altered- meteorite is believed to be in t=
he=20
asteroid belt between Jupiter and Mars. Perhaps you are right and it is not=
=20
"cometary" in nature, but then, EH5 material doesn't belong in the asteroid=20=
belt=20
either, where it is just as much out of place. A very eccentric earlier orb=
it=20
would solve these problems.

Lost City was admittedly something that wasn't convincing, I mentioned it wa=
s=20
simply to be complete, and between you and Elton's clue for verification, I=20
retract it completely as a possibility, at least in my own mind.=A0=20

But: St. Marks (1877) is another story. As one may notice, the 2003 EH1=20
orbit before 1850 had a perihelion around 0.92 AU, and in the 1900's to date=
,=20
around 1.19. Guess what year was the year its orbit (per JPL ephemeris, I a=
ssume=20
reflecting the Jovian adjustments) was most close to 1.00 AU....Earth=20
crossing? answer: just about 1877 !! Is it easy to check, for example in t=
he St.=20
Marks case, if a one ton "fragment" left the 2003 EH1 angular position, how=20=
close=20
it would have to have been to us in the orbital gap to be captured (the=20
radial position difference)? Here is where your having a better facility wi=
th the=20
orbital mechanics calculation could be pretty convincing: How to capture a t=
on=20
of inbound rock close to that orbit, at approximately the same orbital and=20
velocity angle as the main mass (starting inbound at 0.75 AU from Earth on D=
ec=20
21, 1876) for a first approximation, but the closer to Earth, traveling at a=
n=20
Earth velocity component of about 31 km/s towards Earth, also corresponding=20=
to=20
the moment when it is exposed to maximum acceleration since the close approa=
ch=20
point is also its perihelion, solving for the magnitudes of closer radius or=
=20
perturbation in velocity tangent vector necessary to pull the ton to impact=20
here on Earth...keeping in mind that the main mass 2003 EH1 is at 0.52 AU by=
Jan=20
3-4 when the hypothetical ton smashes into the Earth.

To continue further alone this hypothesis regarding St. Marks (EH5 1877), I=20
am quite reasonable agreeing with you that probability alone doesn't favor t=
he=20
conjecture that St Marks was a asteroid/cometary fragment from the orbit of=20
the Quadrantids, and an especially large one at that, among the overwhelming=
=20
typical particles.=A0 What it does have going for it, though, is a fall date=
as=20
Earth approaches the orbit (not recedes) of the meteoroids' distance in the=20=
Solar=20
system plane.=A0 As a matter of fact, the fall date of Jan 3, 1877 seems to=20
have been slightly before the passage of the main mass 2003 EH1. It is=20
noteworthy that it was inbound, too, which could even indicate a bit of grav=
itation=20
acceleration, and furthermore while the main mass was inbound with respect t=
o=20
Earth at a major velocity (Main mass switched velocity direction to away wit=
h=20
respect to earth on Jan 18, 1877 per JPL ephemeris precision), though the cl=
osest=20
approach was Jan 4.

The "proof" (better said, the reason one is comfortable eliminating the=20
possibility of St. Marks as part of the Quandrantids) I seem to understand a=
s being=20
the "cometary" nature of the asteroid or dead comet, 2003 EH1. Nevertheless=
,=20
2003 EH1 seems to be derived IN PART from the Quadrantids now assumed as=20
being the parent body and non-penetrating particulate in nature.=A0 What we=20=
do know=20
is that there is a rock there, but we haven't seen its cometary tail in=20
"life", nor its interior in "death", nor do we know where it was for its fir=
st 4.5=20
billion years.=A0 Further, EH5 classifications were hypothesized possible to=
be=20
derived from the Area of Venus' orbit.=A0 I am way out on a limb here, but i=
t is=20
a good hypothesis I feel, since the heat grade alone isn't convincing at all=
=20
to me...with the understanding that it is improbable, just like another=20
improbability how quickly the particles seem to have uniformized.=A0 Perhaps=
some=20
measurements from the 2003 close approach (relatively close, 17th out of 138=
in=20
rank) gave data on whether 2003 EH1 contained water (St. Marks is anhydrous)=
, or=20
whether there exists a body of knowledge clearly excluding the EH5 meteorite=
=20
composition as being derived from the dead asteroid-comet, which then nails=20
your argument as true.

Thanks for entertaining the ideas, as there aren't many knowns here I'm=20
enjoying very much exploring this issue, with someone like yourselfand this=20=
is the=20
Meteorite interest list, so where else for me...; I have the most respect fo=
r=20
your research into the subject.=A0 If you have further information on the=20
composition of the 2003 EH1 itself or especially vs. an EH5, please let me k=
now.=A0 Is=20
it completely solid, for example?=A0 Thanks again.

Saludos
Doug Dawn
Mexico

En un mensaje con fecha 12/22/2003 6:08:29 PM Mexico Standard Time,=20
marco.langbroek_at_wanadoo.nl escribe:

> Asunto: [meteorite-list] re: Bootids (Quadrantids) meteor shower and 2003=20
> EH1=20
> Fecha: 12/22/2003 6:08:29 PM Mexico Standard Time
> De: marco.langbroek_at_wanadoo.nl
> Para: MexicoDoug_at_aol.com
> CC: meteorite-list_at_meteoritecentral.com
> Enviado por Internet=20
>=20
>=20
>=20
>=20
> >while the DUST distribution seems to have uniformized through
> >the whole orbit in very short timing according to the paper and
> >other sources, observers, etc., a disintegration event would likely
> >still have any larger pieces nearer the main body, right?
>=20
> Hello Dough,
>=20
> That cannot be excluded of course. While called a "parent body", it is
> equally valid to regard 2003 EH1 as just the biggest meteoroid in the
> stream. Indeed, there could be fragments with sizes between the range ends
> defined by 2003 EH1 and normal Quadrantid meteoroids. You are right in tha=
t.
>=20
> Still I do not think this stream is a likely source of meteorites. You poi=
nt
> to the St. Mark's EH5, and Lost City H5 (which anyhow has an orbit unlike
> that of 2003 EH1). St. Mark's is a chondrite with a rather
> high petrologic grade (5), i.e. it has undergone thermal metamorphism.
> Those are not the kind of bodies that I would connect with the clearly
> cometary Quadrantid meteoroids.
>=20
> Cheers,
>=20
> - Marco
>=20
> ------
> Marco Langbroek
> Dutch Meteor Society (DMS)
> Leiden, the Netherlands
> 52.15896 N, 4.48884 E (WGS 84)
>=20
> meteorites_at_dmsweb.org
> http://home.wanadoo.nl/marco.langbroek

--part1_18a.2394c06d.2d195612_boundary
Content-Type: text/html; charset="ISO-8859-1"
Content-Transfer-Encoding: quoted-printable

<HTML><HTML>Hi Marco, 
 
Thanks for the relevant comments including: 
 
>>Still I do not think this stream is a likely source of meteorites. <=
BR>
>>You point to the St. Mark's EH5, and Lost City H5 (which 
>>anyhow has an orbit unlike that of 2003 EH1). St. Mark's is 
>>a chondrite with a rather high petrologic grade (5), i.e. it has <BR=
>
>>undergone thermal metamorphism.=A0 Those are not the kind of 
>>bodies that I would connect with the clearly cometary 
>>Quadrantid meteoroids. 
 
Regarding St. Marks, first let me say that I believe the current main suspec=
ted source of EH5 -thermally altered- meteorite is believed to be in the ast=
eroid belt between Jupiter and Mars.  Perhaps you are right and it is n=
ot "cometary" in nature, but then, EH5 material doesn't belong in the astero=
id belt either, where it is just as much out of place.  A very eccentri=
c earlier orbit would solve these problems. 
 
Lost City was admittedly something that wasn't convincing, I mentioned it wa=
s simply to be complete, and between you and Elton's clue for verification,=20=
I retract it completely as a possibility, at least in my own mind.=A0 
 
But: St. Marks (1877) is another story.  As one may notice, the 2003 EH=
1 orbit before 1850 had a perihelion around 0.92 AU, and in the 1900's to da=
te, around 1.19.  Guess what year was the year its orbit (per JPL ephem=
eris, I assume reflecting the Jovian adjustments) was most close to 1.00 AU.=
...Earth crossing?  answer: just about 1877 !!  Is it easy to chec=
k, for example in the St. Marks case, if a one ton "fragment" left the 2003=20=
EH1 angular position, how close it would have to have been to us in the orbi=
tal gap to be captured (the radial position difference)?  Here is where=
your having a better facility with the orbital mechanics calculation could=20=
be pretty convincing: How to capture a ton of inbound rock close to that orb=
it, at approximately the same orbital and velocity angle as the main mass (s=
tarting inbound at 0.75 AU from Earth on Dec 21, 1876) for a first approxima=
tion, but the closer to Earth, traveling at an Earth velocity component of a=
bout 31 km/s towards Earth, also corresponding to the moment when it is expo=
sed to maximum acceleration since the close approach point is also its perih=
elion, solving for the magnitudes of closer radius or perturbation in veloci=
ty tangent vector necessary to pull the ton to impact here on Earth...keepin=
g in mind that the main mass 2003 EH1 is at 0.52 AU by Jan 3-4 when the hypo=
thetical ton smashes into the Earth. 
 
To continue further alone this hypothesis regarding St. Marks (EH5 1877), I=20=
am quite reasonable agreeing with you that probability alone doesn't favor t=
he conjecture that St Marks was a asteroid/cometary fragment from the orbit=20=
of the Quadrantids, and an especially large one at that, among the overwhelm=
ing typical particles.=A0 What it does have going for it, though, is a fall=20=
date as Earth approaches the orbit (not recedes) of the meteoroids' distance=
in the Solar system plane.=A0 As a matter of fact, the fall date of Jan 3,=20=
1877 seems to have been slightly before the passage of the main mass 2003 EH=
1.  It is noteworthy that it was inbound, too, which could even indicat=
e a bit of gravitation acceleration, and furthermore while the main mass was=
inbound with respect to Earth at a major velocity (Main mass switched veloc=
ity direction to away with respect to earth on Jan 18, 1877 per JPL ephemeri=
s precision), though the closest approach was Jan 4. 
 
The "proof" (better said, the reason one is comfortable eliminating the poss=
ibility of St. Marks as part of the Quandrantids) I seem to understand as be=
ing the "cometary" nature of the asteroid or dead comet, 2003 EH1.  Nev=
ertheless, 2003 EH1 seems to be derived IN PART from the Quadrantids now ass=
umed as being the parent body and non-penetrating particulate in nature.=A0=20=
What we do know is that there is a rock there, but we haven't seen its comet=
ary tail in "life", nor its interior in "death", nor do we know where it was=
for its first  4.5 billion years.=A0 Further, EH5 classifications were=
hypothesized possible to be derived from the Area of Venus' orbit.=A0 I am=20=
way out on a limb here, but it is a good hypothesis I feel, since the heat g=
rade alone isn't convincing at all to me...with the understanding that it is=
improbable, just like another improbability how quickly the particles seem=20=
to have uniformized.=A0 Perhaps some measurements from the 2003 close approa=
ch (relatively close, 17th out of 138 in rank) gave data on whether 2003 EH1=
contained water (St. Marks is anhydrous), or whether there exists a body of=
knowledge clearly excluding the EH5 meteorite composition as being derived=20=
from the dead asteroid-comet, which then nails your argument as true. 
 
Thanks for entertaining the ideas, as there aren't many knowns here I'm enjo=
ying very much exploring this issue, with someone like yourselfand this is t=
he Meteorite interest list, so where else for me...; I have the most respect=
for your research into the subject.=A0 If you have further information on t=
he composition of the 2003 EH1 itself or especially vs. an EH5, please let m=
e know.=A0 Is it completely solid, for example?=A0 Thanks again. 
 
Saludos 
Doug Dawn 
Mexico 
 
 
En un mensaje con fecha 12/22/2003 6:08:29 PM Mexico Standard Time, marco.la=
ngbroek_at_wanadoo.nl escribe: 
 
<BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Asunto: [meteorite-list] re:=
Bootids (Quadrantids) meteor shower and 2003 EH1 
Fecha: 12/22/2003 6:08:29 PM Mexico Standard Time 
De: <A HREF=3D"mailto:marco.langbroek_at_wanadoo.nl">marco.langbroek@wanadoo.n=
l</A> 
Para: <A HREF=3D"mailto:MexicoDoug_at_aol.com">MexicoDoug@aol.com</A> 
CC: <A HREF=3D"mailto:meteorite-list_at_meteoritecentral.com">meteorite-list@m=
eteoritecentral.com</A> 
Enviado por Internet 
 
 
 
 
>while the DUST distribution seems to have uniformized through 
>the whole orbit in very short timing according to the paper and 
>other sources, observers, etc., a disintegration event would likely 
>still have any larger pieces nearer the main body, right? 
 
Hello Dough, 
 
That cannot be excluded of course. While called a "parent body", it is 
equally valid to regard 2003 EH1 as just the biggest meteoroid in the 
stream. Indeed, there could be fragments with sizes between the range ends<B=
R>
defined by 2003 EH1 and normal Quadrantid meteoroids. You are right in that.=
 
 
Still I do not think this stream is a likely source of meteorites. You point=
 
to the St. Mark's EH5, and Lost City H5 (which anyhow has an orbit unlike<BR=
>
that of 2003 EH1). St. Mark's is a chondrite with a rather 
high petrologic grade (5), i.e. it has undergone thermal metamorphism. 
Those are not the kind of bodies that I would connect with the clearly 
cometary Quadrantid meteoroids. 
 
Cheers, 
 
- Marco 
 
------ 
Marco Langbroek 
Dutch Meteor Society (DMS) 
Leiden, the Netherlands 
52.15896 N, 4.48884 E (WGS 84) 
 
meteorites_at_dmsweb.org 
http://home.wanadoo.nl/marco.langbroek</HTML>

--part1_18a.2394c06d.2d195612_boundary--
Received on Tue 23 Dec 2003 03:25:54 AM PST

This message: [ Message body ]
Next message: Bernhard : "[meteorite-list] World of Meteorites"
Previous message: mark ford: "[meteorite-list] TRY THIS !!!!!!"
Next in thread: Marco Langbroek: "[meteorite-list] re: Bootids (Quadrantids), 2003 EH1 & St. Marks meteorite"
Reply: Marco Langbroek: "[meteorite-list] re: Bootids (Quadrantids), 2003 EH1 & St. Marks meteorite"

Mail actions: [ respond to this message ] [ mail a new topic ]
Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

StumbleUpon

del.icio.us

Yahoo MyWeb