The third workshop of SONG The Chinese SONG proposal: scientific concerns Jianning Fu (Beijing Normal University) and Chinese SONG team Beijing ─ March 29, 2010
Contents Scientific goal of Chinese SONGproposal Criteria of target selection Process and results of target selection Test observations Summary and discussion
Scientific goals of the SONG project 1）Make high-precision time-series radial-velocity observations for individual stars brighter than 6th magnitude, to do asterseismological study. 2）Make high-precision high-speed photometric observations for selected fields of the bulge of the Milky Way, to search for exoplanets by means of the micro-lensing effects.
Scientific goal of the Chinese SONG proposal The Chinese-initiated scientific goal： 1) For the selected bright target stars of SONG: Make Johnson BVR simultaneous photometricalobservationsfor the 15′×15′ fields around the target stars, when radial-velocity observations are being made for the target stars 2) For the bright stars selected by Chinese SONG team: Select bright stars in the fields of open clusters Aim： 1) to search for and study in detail the variable objects 2) to make asteroseismology for the pulsating stars
Modifications of the optical paths • Move the lucky image module to the secondary Nasmyth focus; • Place a mirror before the primary Nasmyth focus, • to reflect light of a 15′×15′ FOV to a Wide-Field-Imager Module (WFIM); • 3) Make a hole of 12-mm diameter (92× 92 FOV) at the center of the reflection mirror, to allow the light of the bright target star to go to M4 then to the Coudé train.
WFIM composition 1) Two Dichroic beam-splitters lead light to three CCD cameras equipped with Johnson B、V、Rfilters after a focal reducer; 2) Time-series data of the objects in the 15′×15′ FOV are collected simultaneously with the Coudé train.
WFIM (Light from the telescope)
Targets selected by Chinese SONG team： Stars brighter than 7 magnitudes in V in the fields of open clusters Using long-term networked observation data of SONG, one may do, 1）asteroseismology of pulsating stars in the open clusters; 2）exoplanet detection in the open clusters by transit events; 3）study of binary stars in open clusters.
Number of targets: 813 Potential target stars of SONG V (From the talk of JCD in Beijing in Dec. 2009) B - V
For bright stars: Field and parameter search limits: V magnitude: Min -2, Max 7 B-V: Min 0.4, Max 1.3 For open clusters: close enough to the potential bright stars
Step 1: for bright stars 6477 candidate stars found in Hipparcos Main Catalogue (epoch J 1991.25) with the Multi-parameter search tool; http://www.rssd.esa.int/index.php?project=HIPPARCOS&page=multisearch2
Step 2: for open clusters Download catalog of open clusters from: Dias W. S., Alessi B. S., Moitinho A. and Lépine J. R. D., 2002, A&A, 389, 871 http://www.astro.iag.usp.br/~wilton/
Number of clusters: 1787 Clusters with Diameter: 1782 (99.72%) Clusters with Distance: 1114 (62.34%) Clusters with Reddening: 1093 (61.16%) Clusters with Age: 982 (54.95%) Clusters with Distance, Reddening. and Age: 969 (54.22%) Clusters with Proper Motion (PM): 890 (49.80%) Clusters with Radial Velocity (RV): 502 (28.09%) Clusters with PM + RV: 482 (26.97%) Clusters with Distance, Age, PM and RV: 430 (24.06%) Clusters with Abundance: 178 ( 9.96%)
APPARENT DIAMETER DISTRIBUTION Apparent Diameter (Degree)
Step 3: bright stars in open cluster fields Take the bright stars at the center of the fields, and the edges of the open clusters (OC) located just at the edges of the fields, as the critical situation of targets Separation in RA ≤ (Diameter of OC + Diameter of the field)/2 Separation in DEC ≤(Diameter of OC + Diameter of the field)/2
SELECTED CANDIDATES 254 PAIRS BRIGHT STARS：243 (3.75%) OPEN CLUSTERS：121 (6.77%)
APPARENT DIAMETER OF OPEN CLUSTERS Apparent Diameter (arc minute)
March 2 and 6, 2010: Run I The 80-cm telescope at Xinglong station March 10 and 12, 2010: Run II The 100-cm telescope at Xinglong station Attention: Light of the bright star masked at the center of the window of the CCD camer
The 80-cm telescope • Mounting: equatorial • Made by AstroOptik company of Germany • Equipped with a PI CCD camera of 1340×1300 • Cooling: liquid nitrogen • FOV: 11.5′×11.5′
The 1-m telescope • Mounting: altazimuth • Made by EOS company of Australia • Equipped with a PI CCD camera of 1340×1300 • Cooling: electronic • FOV: 12′×12′
Targets: HIP 29860: RA=06:17:16; DEC=05:06:00; V=5.71; B-V=0.61; Open cluster: Platais 6; RA=06:15:26; DEC=03:50:42; Diameter=4.2°; Sep in RA=27.6′; Sep in DEC=75.3′ HIP 69107: RA=14:08:46; DEC=59:20:16; V=6.47; B-V=1.023; Open cluster: Collinder 285; RA=14:41:06; DEC=69:34:00; Diameter=23.33°; Sep in RA=8°5′; Sep in DEC=10°14′