[IAUC] IAUC 9012: eta Car; QY Mus [25139-2009/08-R1]

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                                                  Circular No. 9012
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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eta CARINAE
     K. Davidson, University of Minnesota; J. C. Martin, University
of Illinois at Springfield; and R. M. Humphreys and A. Mehner,
University of Minnesota, on behalf of a collaboration using the
Gemini telescope (+ GMOS) and the Hubble Space Telescope (+ WFPC2),
report that the current spectroscopic event of eta Car has evolved
faster than the observations of previous events were able to show.
Ultraviolet HST/WFPC2 data are especially noteworthy.  STMAG
magnitudes in a 0".3 virtual aperture with the F250W filter (250
nm) were:  2008 Nov. 12, 6.27; Dec. 7, 6.30; 2009 Jan. 2, 6.21; 7,
6.44; 10, 6.63; 14, 6.96.  Similar data on the 2003 event (Martin
et al. 2006, A.J. 132, 2717) were too sparse to reveal the high
rate of decline (0.06 magnitude/day for almost two weeks); caused
by ultraviolet absorption lines, this rate is impressive because
the opaque stellar wind has a large photospheric size scale of 1-10
AU in the ultraviolet.  Recent WFPC2 data near 330 and 631 nm show
rapid changes with a different pattern.  Gemini/GMOS spectra show
that the equivalent width of the [Ne III] 387-nm line, a classic
event indicator, declined almost linearly from 0.18 nm on 2008 July
17 to near-zero on 2009 Jan. 8.  The exotic He II 468-nm emission
peaked on Jan. 6 +/- 1 and then declined steadily until it was
nearly undetectable on Jan. 15.  The peak equivalent width of this
feature was 0.28 nm, somewhat brighter than the highest value seen
in 2003.  (This result depends strongly on the measurement protocol,
defined in Martin et al. 2006, Ap.J. 640, 474.)  The rapid stage of
the event probably ended about Jan. 15, and the first stage of
recovery should occur during the next six weeks.  Observations with
other instruments are highly recommended.


QY MUSCAE
     Further to IAUC 8990, W. Liller writes that spectra were
obtained by F. M. Walter (Stony Brook University) with the SMART
1.5-m telescope at Cerro Tololo, showing that QY Mus is a typical
"Fe II"-type nova.  On 2008 Dec. 24.3 UT, the H_alpha emission line
(FWHM = 3.2 nm) was seen to peak at about 8.5 times the intensity
of the underlying continuum with a clearly defined wind absorption
feature at -1650 km/s (652.7 nm), and the [O I] lines at 630.0 and
636.4 nm were present.  On Dec. 28.3, in addition to strong Balmer
emission lines (most showing deep wind absorption features), the Fe
II lines of multiplets 42, 48, 49, 57, and 58 were prominent, some
with blueshifted P-Cyg absorption features.  Tech Pan magnitudes by
Liller for QY Mus:  2008 Dec. 18.346, 9.3 (V); 2009 Jan. 7.34, 9.5
(orange filter).

                      (C) Copyright 2008 CBAT
2009 January 20                (9012)            Daniel W. E. Green