stellar variability monitoring in open clusters with mini-song x.b. zhang national astronomical...
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Stellar variability monitoring in open clusters with mini-SONG
X.B. ZhangNational Astronomical
Observatories,Chinese Academy of Sciences
Mini-SONG Overview A global photometry
system;
Shares the sites and operation net-work with the North SONG.
Instruments & parameters:
Double-tube 50 cm reflector;
F/9.5
equatorial mount;
2k×2k CCD;
SDSS or Johnson filters
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.
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.
Why open clusters? More effective for
denser stars; The same evolution
history and environment of member stars;
Definite parameters known from other ways;
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),
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.
Example. 1V12 in NGC188, a detached
binary discovered by Zhang
et al. (2002, 2004)
Zhang, et al., 2002, 2004
Meibom et al., 2009
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.
Transit searching for Jupiter-like planets;
Detailed by Prof. Zhou
Stellar eruptive events.
CVs, flares of late-type stars
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