J/MNRAS/403/545 Young stars in Cepheus OB3b (Littlefair+, 2010)
Rotation of young stars in Cepheus OB3b.
Littlefair S.P., Naylor T., Mayne N.J., Saunders E.S., Jeffries R.D.
<Mon. Not. R. Astron. Soc., 403, 545-557 (2010)>
=2010MNRAS.403..545L 2010MNRAS.403..545L
ADC_Keywords: Associations, stellar ; Photometry, UBVRI ; Photometry, CCD
Keywords: accretion, accretion discs - planetary systems: protoplanetary discs -
stars: pre-main-sequence
Abstract:
We present a photometric study of I-band variability in the young
association Cepheus OB3b. The study is sensitive to periodic
variability on time-scales of less than a day, to more than 20d.
After rejection of contaminating objects using V, I, R and narrow-band
Hα photometry, we find 475 objects with measured rotation
periods, which are very likely pre-main-sequence members of the Cep
OB3b star-forming region.
Description:
I-band CCD images were taken with the Wide Field Camera (WFC) on the
Isaac Newton Telescope (INT) on La Palma, equipped with four thinned
EEV 2kx4k CCDs.
A single field, with the centre of CCD No. 4 pointing at (J2000)
22:55:43.3+62:40:13 was observed, with data being taken on every
night between 2004 September 21 and October 6. This data set will be
referred to as the "short baseline" (SB) data set. Because the SB data
set is not sensitive to periods longer than 7-10d, we augmented it
with two additional data sets, both of which have longer baselines,
but less dense sampling. Additional data were taken with the WFC on
29 nights between 2005 August 23 and November 1. This data set is
referred to as the "long baseline 0" (LB0) data set.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 123 41883 Photometry for the INT WFC field observed
table2.dat 118 704 Data on the detected periodic variables
flags.dat 84 18 Flags
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See also:
J/MNRAS/341/805 : UBVI CCD photometry of Cep OB3b (Pozzo+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 F4.2 --- Field Field number (G1)
6- 10 I5 --- Star Star identification number, within the field
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 23 F6.3 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 36 F5.2 arcsec DEs [0/60] Declination (J2000)
38- 45 F8.3 pix Xpos X position in the CCD image
47- 54 F8.3 pix Ypos Y position in the CCD image
56- 61 F6.3 mag Vmag V magnitude
63- 68 F6.3 mag e_Vmag rms uncertainty on Vmag
70- 71 A2 --- f_Vmag Flag on Vmag, in flags.dat file
73- 78 F6.3 mag V-I V-I colour index
80- 85 F6.3 mag e_V-I rms uncertainty on V-I
87- 88 A2 --- f_V-I Flag on V-I, in flags.dat file
90- 95 F6.3 mag Ha ?=99.999 Hα magnitude (1)
97-102 F6.3 mag e_Ha ?=9.999 rms uncertainty on Ha (1)
104-105 A2 --- f_Ha Flag on Ha, in flags.dat file
107-113 F7.3 mag R-Ha ?=99.999 R-Hα colour index (1)
115-120 F6.3 mag e_R-Ha ?=9.999 rms uncertainty on R-Ha (1)
122-123 A2 --- f_R-Ha Flag on R-Ha, in flags.dat file
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Note (1): When Ha was 99.999, e_Ha, R-Ha and e_R-Ha where set to 99.999 or
9.999 by CDS. Original version of the table is available at
http://www.astro.ex.ac.uk/people/timn/Catalogues/LNMSJ2010/ha_withpos.cat
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 F4.2 --- Field Field number (G1)
6- 10 I5 --- Star Star identification number, within the field
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 23 F6.3 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 36 F5.2 arcsec DEs [0/60] Declination (J2000)
38- 45 F8.3 pix Xpos X position in the CCD image
47- 54 F8.3 pix Ypos Y position in the CCD image
56- 61 F6.3 d Per Period
63- 67 F5.3 d e_Per rms uncertainty on Per
69- 70 A2 --- f_Per Flag on Per, in flags.dat file
72- 77 F6.3 mag Vmag V magnitude
79- 83 F5.3 mag e_Vmag rms uncertainty on Vmag
85- 86 A2 --- f_Vmag Flag on Vmag, in flags.dat file
88- 93 F6.3 mag V-I V-I colour index
95- 99 F5.3 mag e_V-I rms uncertainty on V-I
101-102 A2 --- f_V-I Flag on V-I, in flags.dat file
104-109 F6.3 mag R-Ha ?=99.999 R-Hα colour index
111-115 F5.3 mag e_R-Ha ?=9.999 rms uncertainty on R-Ha
117-118 A2 --- f_R-Ha Flag on R-Ha, in flags.dat file
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Byte-by-byte Description of file: flags.dat
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Bytes Format Units Label Explanations
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1 A1 --- Flag Flag code (1)
3- 49 A47 --- Explain Flag meaning
51- 75 A25 --- Algorithm Algorithm used
77- 82 A6 --- Type Type (Strong or Weak)
84 I1 --- Fno ? Flag number for the older versions of
the software
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Note (1): If a star is flagged as having negative counts (M),
the magnitude is replaced with the uncertainty in flux converted into
magnitudes. Thus magnitudes for objects flagged M should be treated as
bright (i.e. lower) limits. It also means that colours which are
quoted for these objects are limits.
For example a flag of MO in the B-V colour, means that the B magnitude
is a lower limit, so B-V is a lower limit. The uncertainty becomes
meaningless, unless you want the description for real aficionados...
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Global notes:
Note (G1): Field number. Sometimes integer, sometimes real of the form 3.02
where the number after the decimal is the CCD number.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Sep-2010