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J/A+A/502/883 I photometry of very low mass ONC stars (Rodriguez-Ledesma+, 2009)

Rotational studies in the Orion nebula cluster: from solar mass stars to brown dwarfs. Rodriguez-Ledesma M.V., Mundt R., Eisloeffel J. <Astron. Astrophys. 502, 883 (2009)> =2009A&A...502..883R
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Magnitudes Keywords: stars: low-mass, brown dwarfs - stars: pre-main sequence - stars: rotation - stars: starspots - techniques: photometric - stars: activity Abstract: Rotational studies at a variety of ages and masses are important for constraining the angular momentum evolution of young stellar objects (YSO). Of particular interest are the very low mass (VLM) stars and brown dwarfs (BDs), because of the significant lack of known rotational periods in that mass range. We aim to extend previous studies well down into the substellar regime, providing for the first time information on rotational periods for a large sample of young VLM stars and BDs. This extensive rotational period study of YSOs in the 1 Myr old Orion Nebula Cluster (ONC) is based on a deep photometric monitoring campaign using the Wide Field Imager (WFI) camera on the ESO/MPG 2.2m telescope on La Silla, Chile. Time series data was obtained with about 95 data points spread over 19 nights. Accurate I-band photometry of 2908 stars was obtained within a magnitude range of 13 to 21mag, i.e. extending three magnitudes deeper than previous studies in the ONC. Two different power spectral analysis techniques were used to search for periodic variability. In addition, the chi2 variability test was used for the detection of irregular variables. Description: Table 1 lists the 2908 very low mass objects in the Orion Nebula Cluster with magnitudes between 14-21mag in I band for which accurate photometry was performed. It contains the position, brightness and type of variability of these stars, as well as 2MASS counterparts when available. Table 2 lists the 487 objects found to be periodic in this study, for which their brightness, period and peak-to-peak amplitudes a re given, as well as periods measured in Herbst et al. 2002 (Cat. J/A+A/396/513) when available. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 66 2910 Photometric Data table2.dat 63 488 Periodic variables detected during this study
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997) J/A+A/396/513 : Stellar rotation in the Orion Nebula Cluster (Herbst+, 2002) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 I5 --- [H97b] ID number (G1) 7 I1 h RAh Right ascension (J2000) 9- 10 I2 min RAm Right ascension (J2000) 12- 16 F5.2 s RAs Right ascension (J2000) 18 A1 --- DE- Declination sign (J2000) 19 I1 deg DEd Declination (J2000) 21- 22 I2 arcmin DEm Declination (J2000) 24- 28 F5.2 arcsec DEs Declination (J2000) 30- 35 F6.3 mag Imag Average I magnitude (4) 37- 41 F5.3 mag e_Imag Error on I magnitude 43- 44 I2 --- Ndata Number of data points obtained 46 A1 --- Chip CCD chip on which star is located (1) 48- 49 A2 --- Vtype Type of variability (2) 51- 66 A16 --- 2MASS 2MASS (Cat. II/246) identification number (HHMMSSss+DDMMSSs) (3)
Note (1): CCD identification. Each CCD of the mosaic is named from a to h, starting from the upper left corner and going clockwise to the bottom left corner. Note (2): The variability flag column catalogues all objects from their variation properties as follows: NV = non-variable IV = irregular variable PV = periodic variable PP = possible periodic variable PE = possible eclipsing system Note (3): If blank, no 2MASS counterpart found. Note (4): I filter used is ESO filter 851, with central wavelength 851.9nm and width FWHM=20.1nm
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 5 I5 --- [H97b] ID number (G1) 7- 12 F6.3 mag Imag Average I magnitude 14- 21 E8.3 --- FAP(Sc) False Alarm Probability from Scargle periodogram 23- 30 E8.3 --- FAP(Ft) False Alarm Probability from F-test 32- 36 F5.2 d Per Rotation period from this study 39- 43 F5.3 d e_Per Error in the rotation period 45- 49 F5.2 d P(H2002) ?=99.99 Rotational period given by Herbst et al. (2002, Cat. J/A+A/396/513) (1) 52- 57 F6.3 d P(Adopt) Rotation period of star adopted here 59- 63 F5.3 mag PtP Peak-to-peak amplitude of the brightness modulation
Note (1): If blank, no period was detected by Herbst et al. (2002, Cat. J/A+A/396/513) Note (G1): Identification numbers from Hillenbrand 1997 (J/AJ/113/1733) for numbers below 10000, from Herbst et al. (2002, Cat. J/A+A/396/513) for numbers between 10000 and 11115, [H97b] NNNN in Simbad; and from our study for identification numbers above 20000.
Acknowledgements: Maria Victoria Rodriguez-Ledesma ledesma(at)
(End) M. Rodriguez-Ledesma [Max Plank Inst.], P. Vannier [CDS] 09-Jun-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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