PICK OF THE WEEK: Machholz Comet Babies Lead the Way

[SOHO]

As it is making its fourth appearance in the SOHO/LASCO cameras, we didn't think that Comet 96P/Machholz could hold many more surprises for us. Shows how wrong you can be about comets!



More... (http://soho.nascom.nasa.gov/pickoftheweek/old/16jul2012/)

[Rocky_Shorz]

As it is making its fourth appearance in the SOHO/LASCO cameras, we didn't think that Comet 96P/Machholz could hold many more surprises for us. Shows how wrong you can be about comets! On July 14, 2012, just as Comet Machholz entered the LASCO C2 cameras, two of SOHO's ever-diligent comet hunters spotted a pair of much smaller, fainter comets a few hours ahead of Machholz. At first they thought that these were unrelated, but upon closer inspection, it became obvious that these two tiny objects were in fact fragments of Comet Machholz, forging out ahead of their parent body.

Fragmentation events like this are not that uncommon, particularly for Comet Machholz (see http://sungrazer.nrl.navy.mil/index.php?p=news/family_ties), but it is the first time this particular comet has been directly seen doing this! It is unknown exactly when this fragmentation happened, but given that the comets are some 1.4-million kilometers ahead of their parent, it was most likely around one year ago at their previous passage by the Sun. For them to be separated like this, they must have split apart at different speeds -- probably on the order of 25m/s (~45mph) according to approximate calculations. Assuming these fragments survive, they should precede Comet Machholz by half a day or more on its next return in late 2017.

More details of this exciting event can be found at the Sungrazer here: machholz_babies (http://sungrazer.nrl.navy.mil/index.php?p=news/machholz_babies)


A couple of things of interest here. Well, several actually, but there's a couple I'll focus on. First point to note is that these "fragments" are actually ahead of Comet Machholz, and not behind it. "Huh?! How does that work??!" What that means is that these are not "new" fragments in the sense that they happened within the past few days. For these little guys to have been pushed out ahead of the parent, the separation must have occurred quite some time ago -- almost certainly at the last perihelion passage in 2007. Also, the fragments are closer to one another than they are to Machholz, so I would imagine that they probably broke off as one lump that subsequently split in half shortly after, though that's a bit more speculative on my part. Regardless, there would have been some separation velocity between the parent and the fragment(s), and over the course of the past ~5.2yrs, this small difference in velocity has resulted in the distance we see between them right now, which is actually very substantial.

How substantial? Well, the leading fragment is ~05hrs 12mins ahead of Machholz, and let's assume they're moving at 220km/s (a reasonable velocity for Machholz at this point in its orbit). So that's 312mins = 18720 seconds = 4,118,400km. Thus at 220km/s, Comet Machholz has to travel ~4.12million kilometers to reach that same point as the fragment that leads it. So what would have been the separation velocity? Well the orbit of Machholz is approximately 2 billion kilometers long, and it takes 5.28yrs to travel that. Assuming that after one orbit, they are 4.12 million kilometers apart, it means a steady separation velocity of very roughly 20m/s (meters per second), or about 45mph, which really is not a lot for a solar system object. So it only takes a relatively minimal difference in velocity to make a substantial difference in separation after a complete orbit. [*Please see footnote on these calculations.]

I went back to see if this comet was in range of something similar to the X1.4 class Flare on the 12th, could a CME have this effect on the initial X-Ray burst, or possibly the wave that followed?

http://www.rkracht.de/secchi/machholz20070406-2.gif

no activity searching back through Soho...

is that Santa's little helper up there on the right? ;)

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c2/20070407/20070407_2006_c2_512.jpg

seeing it in a few shots close to each other, maybe this is the comet passing through, only 512K resolution, anyone find a better image?

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c2/20070407/20070407_0806_c2_512.jpg

[Rocky_Shorz]

is this it and it's babies passing through last time?

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c2/20070407/20070407_0127_c2_512.jpg

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or did it have a real close encounter...

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c2/20070406/20070406_0950_c2_512.jpg

[Rocky_Shorz]

a day earlier I see this image, could that be it coming into range? huge separation from the other two lights at that time...

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c3/20070405/20070405_2018_c3_512.jpg

[Rocky_Shorz]

this might be right after they broke off...

maybe that's what happened to Nibiru... ;)

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c3/20070405/20070405_1442_c3_512.jpg

[Rocky_Shorz]

it seems to be in view starting on the second, but in a completely different direction...

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c3/20070402/20070402_1518_c3_512.jpg

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on the 3rd it was still heading the same direction...

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c3/20070403/20070403_1142_c3_512.jpg

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c3/20070403/20070403_1418_c3_512.jpg

http://sohowww.nascom.nasa.gov//data/REPROCESSING/Completed/2007/c3/20070404/20070404_1342_c3_512.jpg