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J/A+A/513/A29       RACE-OC project: M11 (NGC6705)           (Messina+, 2010)

RACE-OC Project: Rotation and variability in the open cluster M11 (NGC6705). Messina S., Padmakar Parihar, Koo J.R., Kim S.-L., Rey S.-C., Lee C.-U. <Astron. Astrophys. 513, A29 (2010)> =2010A&A...513A..29M
ADC_Keywords: Clusters, open ; Stars, late-type ; Photometry, UBV Keywords: stars: activity - stars: late-type - stars: rotation - starspots - open clusters and associations: general - open clusters and associations: individual: M11 Abstract: Rotation and magnetic activity are intimately linked in main-sequence stars of G or later spectral types. The presence and level of magnetic activity depend on stellar rotation, and rotation itself is strongly influenced by strength and topology of the magnetic fields. Open clusters represent especially useful targets to investigate the rotation/activity/age connection. The open cluster M11 has been studied as a part of the RACE-OC project (Rotation and ACtivity Evolution in Open Clusters), which is aimed at exploring the evolution of rotation and magnetic activity in the late-type members of open clusters with different ages. Photometric observations of the open cluster M11 were carried out in June 2004 using LOAO 1m telescope. The rotation periods of the cluster members are determined by Fourier analysis of photometric data time series. We further investigated the relations between the surface activity, characterized by the light curve amplitude, and rotation. We have discovered a total of 75 periodic variables in the M11 FoV, of which 38 are candidate cluster members. Specifically, among cluster members we discovered 6 early-type, 2 eclipsing binaries and 30 bona-fide single periodic late-type variables. Considering the rotation periods of 16 G-type members of the almost coeval 200-Myr M34 cluster, we could determine the rotation period distribution from a more numerous sample of 46 single G stars at an age of about 200-230 Myr and determine a median rotation period P=4.8d. A comparison with the younger M35 cluster (∼150Myr) and with the older M37 cluster (∼550Myr) shows that G stars rotate slower than younger M35 stars and faster than older M37 stars. The measured variation of the median rotation period is consistent with the scenario of rotational braking of main-sequence spotted stars as they age. Description: In Table 1, we summarise the results of our period search analysis. In Table 2 we give the time series averaged V-band magnitudes (non corrected for interstellar reddening) for the periodic variables newly discovered in the FoV of M11. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 88 75 Summary of rotation period search table2.dat 33 8141 Photometric time series of periodic variables
See also: J/A+AS/128/255 : Proper motions in M 11 (Su+ 1998) J/A+A/412/721 : CCD Δa-photometry of 5 open clusters (Paunzen+, 2003) J/PASP/119/1233 : BV photometry of M11 stars (Koo+, 2007) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 I5 --- Target Target's internal ID number 7- 11 I5 --- Webda ?=- Target's Webda number (G1) 13- 14 I2 h RAh Right ascension (J2000.0) 16- 17 I2 min RAm Right ascension (J2000.0) 19- 24 F6.3 s RAs Right ascension (J2000.0) 26 A1 --- DE- Declination sign (J2000.0) 27- 28 I2 deg DEd Declination (J2000.0) 30- 31 I2 arcmin DEm Declination (J2000.0) 33- 37 F5.2 arcsec DEs Declination (J2000.0) 39- 45 F7.4 d Per Period from Scargle analysis (2) 46- 52 F7.4 d e_Per Uncertainty on the adopted period 54- 58 F5.2 --- PN Normalized power from Scargle periodogram (2) 60- 64 F5.2 mag <Vmag> Mean V magnitude 66- 70 F5.2 mag (B-V)0 Dereddened B-V color index 72- 77 F6.4 mag Vsig V-band photometric accuracy 79- 84 F6.4 mag Vamp V-band light curve amplitude 86 A1 --- Mm [abn] Membership code (1) 88 A1 --- Ecl [yn] detected eclipse (yes or no)
Note (1): Membership probability flag as follows: n = non members b = low-probability members a = high-probability members Note (2): The Scargle technique has been developed to search for significant periodicities in unevenly sampled data, see Scargle 1982ApJ...263..835S), Horne & Baliunas (1986ApJ...302..757H). The algorithm calculates the normalized power of each frequency PN. The normalized power corresponding to a probability of a false alarm of 1% (i.e. the detected frequency is due to the noise at a probability level of 1%) is PN=9.2.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 5 I5 --- Target Target's internal ID number (G1) 7- 18 F12.4 d HJD Heliocentric Julian Day 20- 26 F7.4 mag Vmag V-band magnitude 28- 33 F6.4 mag e_Vmag Uncertainty on Vmag
Global notes: Note (G1): Wedba numbers: * 1-9804, NGC 6705 NNNN in Simbad * 10095-26763, from Koo et al., 1997, Cat. J/PASP/119/1233
Acknowledgements: S. Messina, sme(at)
(End) Patricia Vannier [CDS] 29-Dec-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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