A bit more news on 209P/LINEAR and the forthcoming Camelopardalid meteor shower:
- Carl Hergenrother (U Arizona) reported his broad-band photometry of P/LINEAR in CBET 3870. His analysis indicated a slow rotator (best fit ~21.86 hr) and a larger-than-expected nucleus (at least 2 km). He also suggested that the comet is only active within 1.4 AU from the Sun.
- There have been a few reports on meteorobs mailing list and noted by the American Meteor Society about some fireballs that looks like Camelopardalid member (northern radiant + slow). I remain skeptical until I see the orbit.
- Peter Jenniskens (SETI) is hosting a great website here and keeping collecting information about P/LINEAR and Camelopardalids. On the post of May 20 he noted the higher chance of seeing lunar meteoroid impacts as calculated by Peter Zimnikoval. The predicted peak time for the moon is about 4h UT on May 24.
- On the same date, Jenniskens also wrote that he and his colleagues detected an annual meteor shower called sigma Ursae Majorids in the CAMS network that appears in mid June. Note that this is actually reported in a submitted paper and he did not note the registered Camelopardalid meteor shower (code 451; this may or may not be the same Camelopardalid meteor shower we used to refer the forthcoming outburst) he mentioned in his earlier study (Rudawska & Jennsikens 2014). It is not clear to me why is this — for example, if these two meteor showers are in fact the same one.
- Jenniskens also reported the measurement by David Schleicher (Lowell) which showed an extremely low activity of P/LINEAR (CBET pending).
For me, I have been trying to learn IRAF to reduce my spectra taken with Gemini in early April at the breaks of my thesis project. Well, I managed to do it at last (mind you, that was an EUREKA moment!), but I am yet to refine it (combining more frames, etc). Initial measurement of cometary emission species of CN, C_2 and C_3 (upper limit is <~10**25 mol/s) agree with David’s suggestion and the conclusion of our earlier study that P/LINEAR seems to be very depleted in dust production. Meanwhile, I also check the daily log of CAMO and I do not see any activity pops up in either optical system or the radar.
Today Apostolos Christou from Armagh Observatory visited our group and brought us a surprise — a fresh-new prediction by David Asher and Robert McNaught (I first learnt the two’s names when I was in grade 6 in primary school when preparing for the Leonids 1999 return). Their prediction kinds of aligned with me and Paul’s prediction, although their timing is more inclined to other predictions (peaks around 7h UT) and their predicted FWHM is shorter (~40 min). They also thought that materials older than 52-rev (~1800) is likely heavily perturbed and is difficult to predict. I talk to Apostolos and Paul about the idea of resonance enhancements (i.e. certain kinds of orbit setups that can reduce the effect of perturbation and preserve strong enhancements within the trail, see the strong and unexpected outburst in 1998 Leonids). They thought that perhaps nobody has taken a closer look into this (Paul said he didn’t), so we probably won’t know until we see it. Keep in mind that surprise can happen!
After all, my thought: we will know in 48 hours. I still think that the activity due to the calculated trails (1800-1900s) will likely be weak (ZHR~10-ish, maybe) and faint (rich in +5 magnitude, maybe) unless we are really lucky (e.g. P/LINEAR is the remnant of a recent catastrophic event or similar things like that). Materials older than 52-rev may have a shoot there, too. My advisor, Peter Brown, also noted that any meteorite-dropper will have to be at least kg-sized, and I don’t see how can an extincting comet do that. But surely we never know…