J/AJ/160/268 Infrared photometry of binaries in Orion OB1 (Tokovinin+, 2020)
Statistics of wide pre-main-sequence binaries in the Orion OB1 association.
Tokovinin A., Petr-Gotzens M.G., Briceno C.
<Astron. J., 160, 268 (2020)>
=2020AJ....160..268T 2020AJ....160..268T
ADC_Keywords: Stars, double and multiple; Stars, pre-main sequence;
Photometry, infrared; Proper motions; Parallaxes, trigonometric;
Spectral types; Positional data
Keywords: Visual binary stars ; Wide binary stars ; Pre-main sequence stars
Abstract:
Statistics of low-mass pre-main-sequence binaries in the Orion OB1
association with separations ranging from 0.6" to 20" (220 to 7400au
at 370pc) are studied using images from the VISTA Orion mini survey
and astrometry from Gaia. The input sample based on the CVSO catalog
contains 1137 stars of K and M spectral types (masses between 0.3 and
0.9M☉), 1021 of which are considered to be association members.
There are 135 physical binary companions to these stars with mass
ratios above ∼0.13. The average companion fraction is 0.09±0.01
over 1.2 decades in separation, slightly less than, but still
consistent with, the field. We found a difference between the Ori OB1a
and OB1b groups, the latter being richer in binaries by a factor of
1.6±0.3. No overall dependence of the wide- binary frequency on
the observed underlying stellar density is found, although in the Ori
OB1a off-cloud population, these binaries seem to avoid dense
clusters. The multiplicity rates in Ori OB1 and in sparse regions like
Taurus differ significantly, hinting that binaries in the field may
originate from a mixture of diverse populations.
Description:
The CIDA Variability Survey of Orion (CVSO) catalog of young stars in
Orion by Briceno+, J/AJ/157/85 served as a starting point for our
target selection.
The Visible and Infrared Survey Telescope for Astronomy (VISTA) Orion
mini Survey provides seeing-limited images with a typical FWHM
resolution of 0.9'. Data were acquired with VIRCAM, the VISTA nIR
wide-field imaging camera that has an average pixel scale of
0.341'/pix. Observations at Z, Y, J, H, Ks bands for one field were
executed sequentially in all filters, spanning no more than 2-3hr in
total.
We matched the VISTA Orion pairs to the list of companions in GDR2 and
thus retrieved the GDR2 astrometry and photometry for all pairs,
except for four close ones with separations below ∼0.7'.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 1137 CVSO-VISTA-Gaia sample
table3.dat 83 490 Companions detected in the VISTA images
table5.dat 45 587 Companions with ΔJ<3mag
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See also:
II/36 : UBV & uvby-beta observations of Orion OB1 Association (Warren+, 1977)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/AJ/129/907 : New Ori OB1 members (Briceno+, 2005)
J/ApJ/661/1119 : Spectroscopy in the 25 Ori group (Briceno+, 2007)
J/AJ/134/2272 : Visual binaries in the Orion Nebula Cluster (Reipurth+, 2007)
J/ApJS/190/1 : A survey of stellar families (Raghavan+, 2010)
J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)
J/AJ/147/87 : From binaries to multiplesII Statistical data (Tokovinin,2014)
J/A+A/581/A140 : VISTA Orion mini-survey (Spezzi+, 2015)
J/A+A/599/A14 : Taurus ultra-wide pairs (Joncour+, 2017)
J/AJ/156/84 : APOGEE-2 survey of Orion Complex. II. (Kounkel+, 2018)
J/ApJS/235/6 : Updated Multiple Star Catalog; August 2019 (Tokovinin, 2018)
J/AJ/157/85 : The CIDA Variability Survey of Orion OB1. II. (Briceno+, 2019)
J/A+A/627/A57 : ONC binary and triple stars (Jerabkova+, 2019)
J/A+A/631/A166 : Members of 5 cluster in Ori OB1a association (Kos+, 2019)
J/AJ/158/48 : Speckle interferometry at SOAR in 2018 (Tokovinin+, 2019)
J/AJ/157/216 : Stellar multiplicity rate M dwarfs within 25pc (Winters+,2019)
J/AJ/159/15 : Binary stars in Upper Scorpius (Tokovinin+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Nint [1/1407] Internal number (G1)
6- 9 I4 --- CVSO [7/2001] CVSO number (G2)
11- 18 F8.5 deg RAdeg [79.5/85.6] Right Ascension (J2000)
20- 27 F8.5 deg DEdeg [-2.09/3.59] Declination (J2000)
29- 33 F5.2 mas plx [-1.75/10.72]? Parallax (1)
35- 38 F4.2 mas e_plx [0/1.32]? Parallax error (1)
40- 45 F6.2 mas/yr pmRA [-61.2/55.85]? Proper motion in R.A. (1)
47- 53 F7.2 mas/yr pmDE [-127.07/56.87]? Proper motion in Dec. (1)
55- 59 F5.2 mag Gmag [0/20.72] Gaia DR2 G-band magnitude
61- 65 F5.2 mag Jmag [10.47/17.01] J-band magnitude
67- 71 A5 --- SpT Spectral type
73- 77 F5.2 --- rerr [0/18.96] Relative parallax error
79- 79 I1 --- Memb [0/2] Membership flag (2)
81- 87 F7.4 arcsec Sep [0/19.96] Binary separation
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Note (1): Null values correspond to missing values in Gaia DR2
Note (2): Membership flags as follows:
0 = astrometric non-member;
1 = member with missing or unreliable astrometry;
2 = astrometric member.
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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- 4 I4 --- Nint [1/1406] Internal number (G1)
6- 9 I4 --- CVSO [11/1914] CVSO number (G2)
11- 15 F5.1 deg PA [0.7/359] Position angle
17- 22 F6.3 arcsec Sep [0.505/11.44]Separation
24- 28 F5.3 arcsec rmsSep [0.001/2.23]RMS scatter of separation
30- 34 F5.2 mag dZmag [-1.35/7.5]? Magnitude difference in Z (1)
36- 40 F5.2 mag dYmag [-1.27/7.5]? Magnitude difference in Y (1)
42- 46 F5.2 mag dJmag [-1.24/7.19]? Magnitude difference in J (1)
48- 52 F5.2 mag dHmag [-1.28/7.04]? Magnitude difference in H (1)
54- 58 F5.2 mag dKmag [-4.44/7.06]? Magnitude difference in K (1)
60- 63 F4.2 mag rmsdZ [0/1.14]? RMS scatter of dZ (2)
65- 68 F4.2 mag rmsdY [0/2.78]? RMS scatter of dY (2)
70- 73 F4.2 mag rmsdJ [0/1.76]? RMS scatter of dJ (2)
75- 78 F4.2 mag rmsdH [0/5.78]? RMS scatter of dH (2)
80- 83 F4.2 mag rmsdK [0/4.94]? RMS scatter of dK (2)
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Note (1): Null if no images in this band are available.
Note (2): Null if no images, 0 if one image
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
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Bytes Format Units Label Explanations
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1- 4 I4 --- Nint [5/1406] Internal number (G1)
6- 9 I4 --- CVSO [11/1895] CVSO number (G2)
11- 15 F5.1 deg PA [0.3/358.2] Position angle
17- 22 F6.3 arcsec Sep [0.5/20] Separation
24- 28 F5.2 mag dJmag [-3.78/2.99] J-band magnitude difference (1)
30- 34 F5.2 mag dGmag [-6/4.74] G-band magnitude difference
36- 38 F3.1 --- pastro [0/1] Astrometric membership flag (2)
40- 45 F6.3 --- pphys [-1/1] Physical relation flag (3)
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Note (1): Median of dY, dJ, and dH
Note (2): Astrometric membership flag as follows:
0.0= astrometric non-member;
0.5= no reliable astrometry;
1.0= member.
Note (3): Values above 0.5 indicate physical companions to members of Ori
OB1. Negative values correspond to physical companions to non-members of
the association.
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Global Notes:
Note (G1): Internal numbers are ordered in RA and range from 1 to 732 for Ori
OB1a and from 1001 to 1407 for Ori OB1b.
Note (G2): Number in Briceno+, J/AJ/157/85.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 12-Feb-2021