![Page 1: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/1.jpg)
Stellar variability monitoring in open clusters with mini-SONG
X.B. ZhangNational Astronomical
Observatories,Chinese Academy of Sciences
![Page 2: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/2.jpg)
contents
Mini-SONG Overview
Main Science goals
Interesting subjects concerned
Predicted results
![Page 3: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/3.jpg)
Mini-SONG Overview A global photometry
system;
Shares the sites and operation net-work with the North SONG.
![Page 4: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/4.jpg)
Instruments & parameters:
Double-tube 50 cm reflector;
F/9.5
equatorial mount;
2k×2k CCD;
SDSS or Johnson filters
![Page 5: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/5.jpg)
Capability & utilities: FOV: 20’×20’ ; image scale of 0.6”/pixel; Photometry precision:
0.008 mag for V=15 and 0.011mag for V=16 ( 1 single exposure);
0.003, 0.005 mag for V=15, 16 respectively (10 exposures combined).
Time-resolution: 1 min.; Duty-cycle: > 40%; Two-color simultaneously.
![Page 6: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/6.jpg)
Main Science goals
Multi-color photometric survey of open clusters; To obtain the unique multi-color CMDs of about 300 nearby
open clusters and determine the basic parameters by isochrone fitting, by single site.
Stellar variability monitoring in open clusters; Long-term, time-series photometry on about 20-30 selected
clusters, each with a time span longer than 1 month.
Follow-up photometry of ToOs such as GRB, SN etc.
![Page 7: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/7.jpg)
Why open clusters? More effective for
denser stars; The same evolution
history and environment of member stars;
Definite parameters known from other ways;
![Page 8: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/8.jpg)
The probable mini-SONG OC targets
337 OCs collected as the
initial candidates, each with the
modest coordinates, distance
modulus (brightness) and
diameters
(http://www.univie.ac.at/webda/webda.html),
![Page 9: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/9.jpg)
Interesting subjects concerned
Eclipsing binaries
Basic data: fraction & distributions in mass ratio,
orbital period etc.;
Test the theory of stellar evolution;
Effects of mass transfer and angular momentum
loss, constraints to the model of binary evolution.
![Page 10: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/10.jpg)
Example. 1V12 in NGC188, a detached
binary discovered by Zhang
et al. (2002, 2004)
Zhang, et al., 2002, 2004
Meibom et al., 2009
![Page 11: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/11.jpg)
Zhang, Deng & Lu, 2009
Example. 2TX Cnc, a W UMa star
In the praesepe cluster
![Page 12: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/12.jpg)
Pulsating stars:
Detect and compile the complete sample of
several types of pulsating stars, SPB, Cephei,
Scuti etc.;
Blue & red edges of the instability stripe for each
types of variables based on large-sample study.
Comparison asteroseismic study with known
physical parameters.
![Page 13: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/13.jpg)
Example. 312 Scuti variables in NGC6811
Luo & Zhang et al., 2009
![Page 14: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/14.jpg)
Example. 4:18 SPBs in NGC7654
Luo, Zhang & Han, 2011
![Page 15: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/15.jpg)
Transit searching for Jupiter-like planets;
Detailed by Prof. Zhou
Stellar eruptive events.
CVs, flares of late-type stars
![Page 16: Stellar variability monitoring in open clusters with mini-SONG](https://reader030.vdocuments.us/reader030/viewer/2022032709/56813253550346895d98d66e/html5/thumbnails/16.jpg)
Predicted results
Unique, high-precision CMDs and basic physical parameters will be determined for about 300 nearby open clusters,;
Light variability of tens of thousands of stars be monitored by continuous, long-term photometry, a discovery of hundreds to thousands of variables in various types is expected;
Transits and some other unexpected events