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Special Notice #137: Possible outburst of LV Vel

AAVSO Special Notice #137

Possible outburst of LV Vel
December 2, 2008

Howard Bond (STScI) announced in Astronomer's Telegram #1858 (2008 Nov 30) that LV Vel, a pulsating variable at the center of the planetary nebula Longmore 4, is currently in the midst of a spectroscopic outburst.  Furthermore, Bond noted in vsnet-alert 10770 (2008 Dec 01) that ASAS-3 has a tentative positive detection at V=14.6, very close to the limiting magnitude of ASAS.  If this detection is real and the photometry accurate, LV Vel has also undergone a photometric outburst of at least two magnitudes.  Photometry of LV Vel is therefore urgently requested.

LV Vel is a pulsating variable of the GW Vir type, with full range amplitudes of about 0.1 magnitudes.  LV Vel is multiperiodic, with periods in the range of several hundred to a few thousand seconds.  Detection of the pulsations with good signal-to-noise will therefore be difficult with telescopes smaller than 0.5-m in aperture.  However, measurements of the mean light level are extremely valuable, and confirmation or rejection of the ASAS-3 detection is urgently needed.

LV Vel is located at the following coordinates (J2000):

RA 10 05 45.80 , Dec -44 21 33.0

Finder charts for the field may be plotted with VSP: http://www.aavso.org/observing/charts/vsp/index.html?pickname=LV%20Vel

The star is surrounded by nebulosity, and it is recommended that DSS charts be plotted by checking the "Use DSS Image" option.

Comparison stars are not yet available in VSP.  However, Bond and Meakes (1990; AJ 100, 788) give calibrations of two nearby comparison stars accurate to 0.05 magnitudes:

Comp 1: USNO-A2.0 0450-10727399, RA 10 05 44.95 , Dec -44 22 50.1 (J2000)
        V=15.44, B-V=+0.65

Comp 2: USNO-A2.0 0450-10725971, RA 10 05 42.13 , Dec -44 22 49.7 (J2000)
        V=15.63, B-V=+1.08

Please report all observations to the AAVSO using the name "LV VEL".

This AAVSO Special Notice was prepared by Matthew Templeton.

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