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Alert Notice 471: Cataclysmic variables to be monitored for HST observations

September 20, 2012: Drs. Boris Gaensicke (Warwick University), Joseph Patterson (Columbia University, Center for Backyard Astrophysics), and Arne Henden (AAVSO), on behalf of a consortium of 16 astronomers, have requested the help of AAVSO observers in monitoring the ~40 cataclysmic variables in the table below in support of Hubble Space Telescope observations in the coming months. The HST COS (Cosmic Origins Spectrograph) will be carrying out far-ultraviolet spectroscopy of ~40 CVs sequentially, with the aim to measure the temperatures, atmospheric compositions, rotation rates, and eventually masses of their white dwarfs.

The primary purpose of the monitoring is to know whether each target is in quiescence immediately prior to the observation window; if it is in outburst it will be too bright for the HST instrumentation. Based on the information supplied by the AAVSO - by you, our observers - the HST scheduling team will make the decision (usually) the evening before the scheduled observing time as to whether to go forward with the HST observations. Thus, your observations will be crucial.

***THE FIRST TARGET TO BE MONITORED IS SDSS J164248.52+134751.4. It is scheduled for 2012 October 11-15 (JD 2456212-2456216); the exact time will be announced closer to the date in an AAVSO Special Notice. During quiescence SDSS1642+1347 is around magnitude V=18.6. Coordinates are given in the table.

Nightly observations are requested beginning immediately and continuing through at least the end of October.***

For CCD observers, simultaneous photometry [shortly before, during, and after the HST observations] would be ideal. B filter would be best for a light curve, although for the magnitude estimates, a V measurement would be best. An uninterrupted light curve would be better than cycling between filters. Visual observations are welcome for any targets bright enough.

Charts for the targets may be created using the AAVSO Variable Star Plotter (VSP) at http://www.aavso.org/vsp. Photometrists should use the appropriate data table supplied for each target.

Please submit your observations to the AAVSO International Database as soon after making them as possible. If you see the target in outburst, please contact the AAVSO immediately and post a message to the Observations and Campaigns & Observations Reports forum (http://www.aavso.org/forum). Please use the Primary name in VSX given in the table when submitting your observations to the AAVSO International Database.

This campaign is being followed on the Observing Campaigns page (http://www.aavso.org/observing-campaigns).

Primary name in VSX RA DEC Type Vmin Vmax  
1RXS J023238.8-371812 02 32 37.96 -37 17 54.9 WZ 18.8 11  
1RXS J105010.3-140431 10 50 10.803 -14 04 36.64 WZ 17    
ASAS J160048-4846.2 16 00 47.46 -48 46 05.07 WZ 17.9 12.6  
AX For 02 19 28.00 -30 45 45.6 SU 18.5 12.2  
BB Ari 02 44 57.77 +27 31 09.3 SU 17.9 12  
BB Dor 05 29 28.59 -58 54 46.3 VY 18 14.3  
BD Pav 18 43 11.919 -57 30 44.85 UG 15.4 12.4  
CC Scl 23 15 31.86 -30 48 47.6 SU 17 13.4  
CU Vel 08 58 33.03 -41 47 51.7 SU 17 10.7  
CW Mon 06 36 54.58 +00 02 17.3 DN 16.8    
DT Oct 18 40 52.31 -83 43 10.0 SU 16.5 11.8  
FL Psc (ASAS J002511+1217.2) 00 25 11.14 +12 17 12.1 WZ 17.5 10.5  
GW Lib 15 19 55.34 -25 00 24.58 WZ 16.5 8  
GZ Cet 01 37 01.06 -09 12 34.4 SU 18.7    
HM Leo 09 38 36.99 +07 14 55.0 UG 17.5 13  
HS 0218+3229 02 21 33.48 +32 43 23.9 UG 15.5 12.5  
HS 0220+0603 02 23 01.66 +06 16 49.7 VY 19 19  
HS 0455+8315 05 06 48.23 +83 19 23.4 VY 19 19  
HS 2214+2845 22 16 31.19 +29 00 19.7 DN 16.8 12.5  
IR Com 12 39 32.02 +21 08 06.4 SU 18 13.5  
IU Leo 10 57 56.29 +09 23 14.8 UGSS 15.5 12.9  
IY UMa 10 43 56.74 +58 07 32.1 SU 18.4 13  
LN UMa 10 04 34.75 +66 29 15.0 VY 18.5 18  
LT Eri (SDSS J040714.78-064425.1) 04 07 14.78 -06 44 25.0 UG 17.8    
MR UMa 11 31 22.39 +43 22 38.5 SU 16.7 12.3  
PU CMa 06 40 47.69 -24 23 13.9 SU 16.2 11  
QZ Lib 15 36 15.97 -08 39 07.68 WZ 17.5 11.5  
QZ Ser 15 56 54.47 +21 07 19.0 SU 17.9 12.7  
RZ Leo 11 37 22.27 +01 48 58.6 SU 18.7 11.1  
SDSS J001153.08-064739.1 00 11 53.08 -06 47 39.2 DN 17.8 15  
SDSS J075507.70+143547.6 07 55 07.72 +14 35 47.6 WZ 18.2    
SDSS J093249.57+472523.0 09 32 49.58 +47 25 23.2 DN 17.9    
SDSS J100515.38+191107.9 10 05 15.41 +19 11 07.5 DN 18.2 12.3  
SDSS J100658.40+233724.4 10 06 58.42 +23 37 24.6 UG 18.3    
SDSS J103533.03+055158.4 10 35 33.03 +05 51 58.6 DN 18.8    
SDSS J143544.02+233638.7 14 35 44.02 +23 36 38.7 DN 18.2    
SDSS J153817.35+512338.0 15 38 17.31 +51 23 38.0 DN 18.6    
SDSS J154453.60+255348.8 15 44 53.60 +25 53 48.9 UG+E 15.7 <18  
SDSS J164248.52+134751.4 16 42 48.51 +13 47 51.5 DN 18.6    
V0380 Oph 17 50 13.63 +06 05 29.3 VY 17.9 14.3  
V0405 Peg 23 09 49.14 +21 35 17.2 UG 17.9 13  
V0406 Vir (SDSS J123813.73-033932.9) 12 38 13.73 -03 39 32.8 DN 17.8    
V0482 Cam 07 33 41.41 +67 32 15.6 VY 18.7 18.7  
V0485 Cen 12 57 23.18 -33 12 05.7 DN 18.2 14  
V1108 Her 18 39 26.21 +26 04 08.9 WZ 17.7 10.4  
V1294 Tau 04 00 37.25 +06 22 45.8 VY 19 19  


Your observations and their timely reporting are critical to the success of this campaign. Many thanks for your contributions!

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

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