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IAUC 8883: V458 Vul; C/2007 K19, C/2007 K20, C/2007 L1-L6

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                                                  Circular No. 8883
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://www.cfa.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

     D. K. Lynch, R. W. Russell, and R. J. Rudy, The Aerospace
Corporation; and C. E. Woodward, University of Minnesota, report
0.8- to 5.5-micron spectroscopy of V458 Vul (cf. IAUC 8863, 8878)
on Oct. 10 and 11 UT using the Infrared Telescope Facility (+ SpeX):
"V458 Vul has the strongest lines of neutral helium that we have
encountered in a nova.  He I 1083.0-nm has an equivalent width of >
1400 nm and is 30 times larger than Paschen-beta.  Similarly, He I
2058.1-nm is seven times as strong as Brackett-gamma.  Numerous
other lines of He I are present.  The lines of both helium and
hydrogen are flat-topped and have FWHM of 2700 km/s.  The O I lines
are still present and indicate a reddening of E(B-V) = 0.6.  He II
features are just beginning to emerge, so the He I features will
likely weaken slightly in the future as more helium becomes doubly
ionized.  No thermal emission from dust was detected."

COMETS C/2007 K19, C/2007 K20, C/2007 L1-L6 (SOHO)
     Further to IAUC 8882, additional Kreutz sungrazing comets have
been found on SOHO website images.  C/2007 K19 and L5 were
extremely faint (mag about 8.5) and diffuse, the former being also
elongated.  C/2007 K20 and L6 were very faint (mag about 8) and
diffuse.  C/2007 L1 was stellar in appearance in C3 images, and
slightly diffuse (mag about 7.5) with no tail in C2 images.  C/2007
L2 was stellar in appearance in C3 images, and was of mag about 5.5
with an extremely faint, thin tail in C2 images.  C/2007 L3 peaked
at mag about 3 with a dense, wide tail about 45" long on June 8.171
UT; while the comet's "head" disappeared at about June 8.181, the
tail was still visible at June 8.917 (when it had extended into a
diffuse arc of apparent length around 1.5 deg), and this comet was
also visible in coronagraphs on both STEREO spacecraft.  C/2007 L4
was stellar in appearance (mag about 8).

 Comet        2007 UT      R.A.(2000)Decl.   Inst.  F    MPEC
 C/2007 K19   May 28.326   4 17.0   +19 32   C2     RK   2007-T93
 C/2007 K20       31.129   4 29.8   +20 02   C2     TH   2007-T93
 C/2007 L1    June 4.305   4 46.4   +20 13   C3/2   BZ   2007-T94
 C/2007 L2         4.971   4 52.1   +18 39   C3/2   KB   2007-T94
 C/2007 L3         6.388   4 56.3   +18 10   C3/2   SY   2007-T94
 C/2007 L4         7.704   4 59.0   +20 53   C2     BZ   2007-T94
 C/2007 L5         9.371   5 03.7   +20 56   C2     AW   2007-T94
 C/2007 L6        10.621   5 08.4   +21 06   C2     BZ   2007-T117

                      (C) Copyright 2007 CBAT
2007 October 20                (8883)            Daniel W. E. Green

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