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 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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 66 2910 Photometric Data
table2.dat 63 488 Periodic variables detected during this study
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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
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Bytes Format Units Label Explanations
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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)
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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
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Byte-by-byte Description of file: table2.dat
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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
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Note (1): If blank, no period was detected by Herbst et al. (2002, Cat.
J/A+A/396/513)
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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.
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Acknowledgements:
Maria Victoria Rodriguez-Ledesma ledesma(at)mpia.de
(End) M. Rodriguez-Ledesma [Max Plank Inst.], P. Vannier [CDS] 09-Jun-2009