Yummy!!! ISON is coming back (but, umm…)

Last week, I told you about the glories of comet ISON. Most of my words were, “Don’t miss ISON when it comes back on December!!!”. Then, I also mentioned that NASA/ESA fellas are planning to view the comet’s activity via SOHO’s eyes. On Thanksgiving day (yesterday, at 18:25 UTC), ISON crossed the perihelion with flying colors. And, just as expected, SOHO’s LASCO (C2 & C3) saw the comet swimming through a solar wind that was just ejected by Sun (made of a swarm of charged particles and EM radiation traveling around 200 km/s)…

Timelapse of ISON from Nov. 27 – Dec. 1, captured by SOHO’s LASCO C3

(the white circle in all those captures represent our sun, to scale)

Well, SOHO was unable to see the perihelion because it’s at Lagrange point L1. In other words, it’s exactly in front of Earth. STEREO (A & B) on the other hand somewhere behind the sun, saw the event with its red eyes. Both the spacecrafts didn’t cover the perihelion (because, the curvature of the hyperbolic orbit is far inside the corona – only a million km from sun). Once the comet entered the field of view again (after few hours), it appeared very bright in its magnitude and we breathed a sigh. When we were all happy that ISON survived the catastrophe, data from SOHO’s LASCO C2 on the event gave us a terrible shock. It’s (quite unexpected) anomaly, ISON was headless

Within this 13-hour interval captured by C2, you can see ISON at its brightest magnitude, as it gets very near to the sun, which then disappears out of SOHO’s field of view and finally, comes back in three hours as a headless silhouette. We’ve speculated that the comet’s nucleus has been ripped off by our sun’s wrath. As you can see, only the remnant’s coming back (probably stream of dust remains & few vaporized leftover rocks out of the 2-km sized nucleus)…

Comets (especially sun-grazing ones) are something we don’t know much about. They always come with surprises. What they really do, how they form, what they’re made of, would they survive the extreme heat from our sun, etc. are some of the unanswered questions. This doesn’t mean that we don’t know anything about them. We have vague answers. A few comets satisfy those, while rare species like ISON, will always be our bad luck…

Phil Plait says,

“Predicting comets is like predicting cats. Good luck with that…

Bruce Betts (of the Planetary society) says,

“It is now clear that Comet ISON either survived or did not survive, or… maybe both. Hope that clarifies things.”

And XKCD too, has made a nice comic on the catastrophe

Even now, we don’t know whether the comet has survived or not (in this context, “survive” could either mean, “it’s not dead” or “bright enough for us to see”). After a few hours (around 20:00 UTC), whatever that’s left out of ISON (that long tail-like stream of dust) was visible to the eyes of SOHO and STEREO. The white circles in all the images represent the sun (to scale).

…captured by SOHO’s LASCO C1 when it re-entered the field of view (it appeared very bright, maybe that’s how reflective cameras work)…

…that leftover pixie dust came out after a few hours of the comet’s disappearance, when C2 spotted it.

Also, we don’t know whether we can see this horrible thing during the month of December. Anyhow, most of us are sad that the prodigal son will never appear in the morning skies. In fact, I myself never got the opportunity to see it once in the sky (it was very cloudy here, during the late November). Again, (as I usually say) we can’t blame Nature for our foolishness. It doesn’t make events for satisfying our desires. It just goes on, by its own unpredictable way. So, we (having incomplete information about the event) shouldn’t speculate, “this goes like this”, “this goes like that”, etc…

For what it’s worth, it was a fantastic event for sure, that it attracted all of us. Still, I can’t give it away like that. After all, it’s the last time we’re gonna see it. But, WHO KNOWS? Over the few hours, the comet brightened, got out of sight, brightened and faded again. Why shouldn’t there be a chance that it will get brighter again? (and the vice versa too). I’ll update this post (if I got any info)…

A special thanks to Comet ISON News (in twitter) because they did the marvelous job of updating us, astronomy-lovers every 10 minutes with the latest images of ISON, captured by SOHO & STEREO spacecrafts.

UPDATE: I won’t speculate anything from now..!!!

Everyone’s having the same question…

“Can ISON be seen on December?”

The experts are also wondering the same. We can’t gather sufficient data to convince ourselves because, the comet is still close to the sun. So, we don’t know whether there’s still a nucleus, debris or something.

Meanwhile, the telescopes of STEREO craft, named SECCHI COR-2 (A & B) have caught more images of the prodigal mate (shown to the side). The coronagraph GIFs are quite large in size (Yep), as each have around 120 frames. But, they’re worth.. These captures are softly patting us in the back, that comet ISON can still be ALIVE.

So… from now on… I won’t put any of my hypothesis forward, shouting that the great ISON is dead, it can’t be seen this month, etc. (Can’t even rely on a comet… sigh)

Anyways, for now, the apparent magnitude of ISON is around +5. Within the first week of December, if its brightness increases (the magnitude, being in a logarithmic scale, actually decreases), we’ll be able to spot it. Again, WHO KNOWS? It has surprised us for about twenty times in the last two days. From now, let’s just hope that something amazing happens at the start of December…

UPDATE 2: Slowly fading away from sight… (R.I.P?)

SOHO’s LASCO image at 16:00 UTC shows that the comet’s leftover dusty debris is fading away. It’s getting farther and farther from SOHO’s field of view. It’s about to leave soon and as far as we know, it’s highly unlikely for the comet to be visible to the naked eyes during the first week of December. It maybe visible for binocular-ish observers, early in the morning in a perfect sky (which seems improbable), far away from the cities, sub-urban maybe (makes it worse).

Anyways, our only hope is the end of December (probably during Christmas), when ISON will be very close to Earth (about half the distance from the sun, if I recall correctly). Let’s just hope (though I personally doubt an amazing phenomena like the “comet visible to naked eyes” will happen)…

____________________________________________________________________

If you need any kind of ISONic update, follow the tweets here. I’ve selected a few people who’ll update you with “any-information-they-get” on the hash-tag #ISON.

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