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J/A+A/382/92           Sco OB2 association                      (Shatsky+, 2002)

The mass ratio distribution of B-type visual binaries in the Sco OB2 association Shatsky N., Tokovinin A. <Astron. Astrophys. 382, 92 (2002)> =2002A&A...382...92S
ADC_Keywords: Stars, OB ; Stars, double and multiple ; Photometry, infrared Keywords: binaries: visual - stars: statistics; formation Description: To investigate the dependence of (visual) binarity characteristics on the primary component mass, we selected all stars of spectral type B in Sco OB2 association and searched for near-infrared companions to them with ADONIS and Coronograph. The data acquisition and companions measurement results are described; the mass ratio distribution f(q)=q**(-0.5) is derived using the PMS stars evolution tracks. Target stars J- and K-magnitudes are presented in Table 1; differential photometry and astrometry results for secondary companions and background sources in sky-offset fields are given in Table 2 and 3, respectively. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 58 115 Target star photometry table2.dat 63 96 Secondaries photometry and positions table3.dat 38 97 Background sources data
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HD HD number of target star 8- 15 A8 --- SpType MK spectral classification (from Simbad) 17- 20 F4.2 mag Vmag V magnitude (from Simbad) 22- 25 F4.2 mag Av Interstellar extinction in the visible (1) 27- 30 F4.2 mag Kmag K-band (2.2um) magnitude (2) 32- 35 F4.2 mag e_Kmag ? Error of Kmag (3) 37- 41 F5.2 mag J-K ? (J-K) color index (absent for HD 143275) 43- 46 F4.2 mag e_J-K ? Error of (J-K) (4) 48 I1 --- Nobs Number of observations (pointings) 50 I1 --- Nphys Number of physical companions around 52 I1 --- Nopt Number of optical companions around 54 I1 --- Nsky Number of stars in sky-offset field 56- 58 A3 --- Flag [ANTcjs+] flags (5)
Note (1): Taken from deGeus et al. (1989A&A...216...44D) or, if `A' is given in the field Flag, estimated from (B-V) color excess. Note (2): For non-observed objects the theoretical K magnitude is given as computed from SpType, Vmag and Av Note (3): Error is a deviation of observation results from the mean if Nobs>1 or difference between magnitudes by two halves of data cube if Nobs=1. Not given for non-photometric condition observations (`c' or `+' in Flag) or for objects which weren't observed explicitly (`N' in Flag) Note (4): Error is quadratically added e_Kmag and e_Jmag. See note (3) also. Note (5): Flags meaning: A - extinction is estimated from color excess E(B-V) N - not observed explicitly T - object studied in Tokovinin et al., 1999A&A...346..481T c - non-photometric conditions + - "likely" photometric conditions: K and J-K don't deviate much from expected but night is not photometric j - joint magnitudes of the very close pair are given s - a few pixels of detector in the core of image were near saturation limit
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HD HD number of target star 8- 9 A2 --- ID Component identifier (1) 11- 15 F5.2 mag Kmag K-band magnitude as K(primary) + delta(K) 17- 20 F4.2 mag e_Kmag ? Error: deviation of delta(K) from mean 22- 26 F5.2 mag J-K ? (J-K) color as (J-K)(primary) + delta(J-K) 28- 31 F4.2 mag e_J-K ? Error: deviation of delta(J-K) from mean 33- 34 A2 --- Flag [c+!?: ] flags (2) 36- 41 F6.3 arcsec Rho Separation from primary 43- 47 F5.3 mas e_Rho Error of Rho (in milliarcseconds) 49- 53 F5.1 deg PA position angle 55- 57 F3.1 deg e_PA Error of PA 59 I1 --- Nobs Number of observations (pointings) 61- 62 A2 --- Status [PO? ] `P'-physical,`O'-optical (`?'-uncertain)
Note (1): Taken from the literature for known companions, assigned as `P' or `Q' for new likely physical companions, or assigned numerically as `1',`2',... in increasing order of separation for opticals. Followed by "?" for (two) new companions with uncertain detection. Note (2): Flags meaning: c - non-photometric conditions + - "likely" photometric conditions: K and J-K of primaries don't deviate much from expected but night is not photometric ! - new physical companion : - pair is too close for reliable measurements
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 6 I6 --- HD HD number of target star 8 A1 --- ID [abcdefghi] background star identifier 10- 13 F4.1 mag Jmag ? J-band (1.2mu) magnitude 15- 17 F3.1 mag e_Jmag ? error: spread of different observations 19- 22 F4.1 mag Kmag K-band (2.2mu) magnitude 24- 26 F3.1 mag e_Kmag ? error: spread of different observations 28 A1 --- Flag [c+] flag (1) 30- 33 F4.1 arcsec delRA Coordinate difference with target in right ascension direction 35- 38 F4.1 arcsec delDE Coordinate difference with target in declination direction
Note (1): Flags meaning: c: non-photometric conditions +: "likely" photometric conditions: K and J-K of primaries don't deviate much from expected but the night is not photometric
Acknowledgements:
(End) Patricia Bauer [CDS] 09-Nov-2001
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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