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 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:
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FileName Lrecl Records Explanations
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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
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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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)
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Note (1):
Taken from deGeus et al. (1989A&A...216...44D 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 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
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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- 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- 59 I1 --- Nobs Number of observations (pointings)
61- 62 A2 --- Status [PO? ] `P'-physical,`O'-optical (`?'-uncertain)
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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
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number of target star
8- 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- 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
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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
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Acknowledgements:
(End) Patricia Bauer [CDS] 09-Nov-2001