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ATEL #10142

Title: A New Active Stage of the Symbiotic Star CH Cygni

Author: Takashi Iijima (INAF Astronomical Observatory of Padova, AsiagoStation)
Queries: takashi.iijima@oapd.inaf.it
Posted: 4 Mar 2017; 04:22 UT
Subjects:Optical, Cataclysmic Variable, Star, Variables

The spectral variation of the symbiotic star CH Cygni has been monitored at Asiago Astrophysical Observatory using the 1.22m Galileo telescope.
Recently, P Cygni type high velocity absorption components appeared on the H I Balmer lines, which were not seen in early December 2016. The blue-shifts of the absorption components from the narrow emission ones were -1890 km/s on 2017 Jan. 24.20 UT, -2040 km/s on Feb. 15.19, -2240 km/s on Feb. 26.13,
and -1930 km/s on March 3.16. The equivalent widths of those of H_beta on respective date were 0.16, 0.17, 0.32, and 0.09 nm, and their FWHMs were roughly 0.6 nm. This object has probably entered a new active stage.




It’s all about the  standstills, those episodes where the star gets stuck at a mid-point between maximum and minimum. If it doesn’t exhibit standstills it isn’t a Z Cam star.









AM Her stars in need of further investigation








Data from Catalina Real Time Survey 
Drake et al. 2009, ApJ, 696, 87

Northern CVs brighter than 17th magnitude here.

Southern CV's brighter than 17th magnitude here.



ACTIVITY AT A GLANCE

New outbursts and unusual activity reported in the last 72 hours

Last updated 12:59 UT April 25, 2017

YYYYMMDD

20170423
YZ Cnc
V485 Cen
V803 Cen
BR Lup
V587 Lyr
BI Ori
BV Pup
EK TrA
SY Vol
DDE 76
DDE 77



# indicates a noteworthy or unusual outburst
:  indicates confirmation required
 
'Activity At A Glance' is gleaned from observations reported to AAVSO MyNewsFlash, BAAVSS-Alert, CVnet-Outburst, VSObs-share and VSNET-outburst. We sincerely thank all the observers who contribute timely observations and reports of activity to these email lists.

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