J/ApJ/811/85 RVs & V-band LCs of probable members of Cyg OB2 (Kiminki+, 2015)
Predicting GAIA's parallax distance to the Cygnus OB2 association
with eclipsing binaries.
Kiminki D.C., Kobulnicky H.A., Vargas Alvarez C.A., Alexander M.J.,
Lundquist M.J.
<Astrophys. J., 811, 85 (2015)>
=2015ApJ...811...85K 2015ApJ...811...85K (SIMBAD/NED BibCode)
ADC_Keywords: Radial velocities ; Photometry, UBV ; Binaries, spectroscopic
Keywords: binaries: close; binaries: general; binaries: spectroscopic;
stars: early-type; stars: kinematics and dynamics;
techniques: radial velocities
Abstract:
The Cygnus OB2 Association is one of the nearest and largest
collections of massive stars in the Galaxy. Situated at the heart of
the "Cygnus X" complex of star-forming regions and molecular clouds,
its distance has proven elusive owing to the ambiguous nature of
kinematic distances along this l~=80° sightline and the heavy,
patchy extinction. In an effort to refine the three-dimensional
geometry of key Cygnus X constituents, we have measured distances to
four eclipsing double-lined OB-type spectroscopic binaries that are
probable members of Cyg OB2. We find distances of 1.33±0.17,
1.32±0.07, 1.44±0.18, and 1.32±0.13kpc toward MT91 372,
MT91 696, CPR2002 A36, and Schulte 3, respectively. We adopt a
weighted average distance of 1.33±0.06kpc. This agrees well with
spectrophotometric estimates for the Association as a whole and with
parallax measurements of protostellar masers in the surrounding
interstellar clouds, thereby linking the ongoing star formation in
these clouds with Cyg OB2. We also identify Schulte 3C (O9.5V), a 4"
visual companion to the 4.75 day binary Schulte 3(A+B), as a
previously unrecognized Association member.
Description:
Optical spectroscopic observations of the four targets were obtained
as part of the Cygnus OB2 Radial Velocity Survey on numerous dates
between 2001 and 2011 using a variety of telescopes and instruments as
described in Papers I-IV (see References section below) of this series.
Several additional observations were obtained in 2012 October
(on MT91 696 and Schulte 3) and 2013 May-June (on MT91 372) using the
Wyoming Infrared Observatory (WIRO).
Photometry of MT91 696 was obtained on nine nights between 2012
October 17 and November 10 at the University of Wyoming 0.6m Red
Buttes Observatory (RBO). Data on Schulte 3 was obtained on 14 nights
at RBO between 2012 October 17 and December 21, and data
on CPR2002 A36 was obtained on four nights between 2012 December 10
and 22. Photometry of MT91 372 was also obtained at RBO on seven
nights between 2013 June 14 and July 8.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 68 86 Radial Velocities for MT91 372, MT91 696,
CPR2002 A36, & Schulte 3
table2.dat 22 724 V-band Photometry of MT91 372
table3.dat 22 278 V-band Photometry of CPR2002 A36
table4.dat 22 566 V-band Photometry of MT91 696
table5.dat 22 2108 V-band Photometry of Schulte 3
table7.dat 342 4 Joint light and velocity curve analysis for
MT91 372, MT91 696, CPR2002 A36, and Schulte 3
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See also:
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
III/195 : Atlas of Optical Spectral Classification OB Stars (Walborn+ 1990)
J/MNRAS/449/741 : The massive star population of Cygnus OB2 (Wright+, 2015)
J/ApJS/213/34 : Velocities of Cygnus OB2 massive binaries (Kobulnicky+, 2014)
J/AJ/145/125 : Spectroscopy & HST photometry in Westerlund 2 (Vargas+, 2013)
J/AJ/145/9 : BVRI LCs of the early-type binary V382 Cyg (Yasarsoy+, 2013)
J/A+A/543/A101 : OB stars in Cygnus OB2 association (Comeron+, 2012)
J/ApJ/751/4 : RVs of massive stars in Cyg OB2 (Kiminki+, 2012)
J/ApJ/720/679 : Optical spectroscopy in Cygnus X region (Beerer+, 2010)
J/ApJ/713/871 : Sources in region Cyg-OB2 from X-ray (Wright+, 201)
J/AJ/137/3358 : Speckle interferometry of massive stars (Mason+, 2009)
J/A+A/495/231 : Multiwavelength study of Cyg OB2 5 (Linder+, 2009)
J/A+A/476/1243 : Millimeter continuum mapping of Cygnus X (Motte+, 2007)
J/ApJ/664/1102 : RV survey of Cyg OB2 association (Kiminki+, 2007)
J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)
J/AJ/106/2096 : Limb-darkening coefficients in binaries (Van Hamme 1993)
J/AJ/101/1408 : Massive stars in Cyg OB2. (Massey+ 1991)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Star Star designation
13- 21 F9.3 d HJD Heliocentric Julian date; HJD-2400000.0
23- 27 F5.3 --- Phase Phase
29- 34 F6.1 km/s RVel1 [-248/256]? Primary's radial velocity
36- 40 F5.1 km/s e_RVel1 [3/105]? Uncertainty in RVel1
42 A1 --- f_RVel1 [a] a: Observation not used in solution fit
44- 48 F5.1 km/s (O-C)1 [-56/90]? Primary's (O-C) value
50- 55 F6.1 km/s RVel2 [-320/306]? Secondary's radial velocity
57- 60 F4.1 km/s e_RVel2 [1/46]? Uncertainty in RVel2
62 A1 --- f_RVel2 [a] a: Observation not used in solution fit
64- 68 F5.1 km/s (O-C)2 [-51/99]? Secondary's (O-C) value
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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- 9 F9.3 d HJD Heliocentric Julian date; HJD-2400000.0
11- 16 F6.3 mag Vmag [14.9/15.6] The V band magnitude
18- 22 F5.3 mag e_Vmag [0.003/0.1] The 1σ uncertainty in Vmag (G1)
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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- 9 F9.3 d HJD Heliocentric Julian date; HJD-2400000.0
11- 16 F6.3 mag Vmag [11.3/11.9] The V band magnitude (1)
18- 22 F5.3 mag e_Vmag [0.002/0.005] The 1σ uncertainty in Vmag (G1)
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Note (1): The photometry in the table was binned in two minute intervals
before analysis.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d HJD Heliocentric Julian date; HJD-2400000.0
11- 16 F6.3 mag Vmag [12/12.7] The V band magnitude (1)
18- 22 F5.3 mag e_Vmag [0.001/0.07] The 1σ uncertainty in Vmag (G1)
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Note (1): The photometry includes the contribution from a blended 0.02"
tertiary component, MT91 696c.
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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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1- 9 F9.3 d HJD Heliocentric Julian date; HJD-2400000.0
11- 16 F6.3 mag Vmag [10.1/10.5] The V band magnitude (1)
18- 22 F5.3 mag e_Vmag [0.001/0.03] The 1σ uncertainty in Vmag (G1)
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Note (1): The photometry includes the contribution from a tertiary component,
Schulte 3c. Additionally, the photometry in the table was binned in
two minute intervals before analysis.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Star Star designation
13- 20 F8.6 d Per [1.4/4.8] orbital period
22- 29 F8.6 d e_Per [0/0.0006] Period uncertainty
31- 40 F10.4 d T0 [53996/56101] Date of periastron
42- 47 F6.4 d e_T0 [0.0005/0.2] T0 uncertainty
49- 53 F5.3 --- ecc [0/0.05] Eccentricity
55- 59 F5.3 --- e_ecc [0.002]? ecc uncertainty
61 A1 --- f_ecc f: fixed
63- 66 F4.1 Rsun a [16.3/38.7] Semimajor axis
68- 70 F3.1 Rsun e_a [0.2/0.9] a uncertainty
72- 75 F4.2 --- q [0.4/0.8] Mass ratio
77- 80 F4.2 --- e_q [0.01/0.03] q uncertainty
82- 86 F5.1 km/s V0 [-47/1.1] Systemic velocity (γ)
88- 90 F3.1 km/s e_V0 [2/3] V0 uncertainty
92- 95 F4.1 deg inc [59.2/86.5] Orbital inclination
97- 99 F3.1 deg e_inc [0.3/1.5] inc uncertainty
101-102 I2 % 3l [12/14]? third light contribution
104 A1 --- f_3l f: fixed
106-108 F3.1 [cm/s2] loggP [3.3/4.2] Log of surface gravity (P)
110-112 F3.1 [cm/s2] loggS [3.3/4.1] Log of surface gravity (S)
114-118 I5 K T1 [24000/38500] Primary temperature
120-123 I4 K e_T1 [600/3000]? T1 uncertainty
125-129 I5 K T2 [16600/31300] Secondary temperature
131-134 I4 K e_T2 [600/2300] T2 uncertainty
136-140 F5.2 Rsun R1 [4.9/16.5] Primary radius
142-145 F4.2 Rsun e_R1 [0.03/0.1] R1 uncertainty
147-151 F5.2 Rsun R2 [3.3/13.1] Secondary radius
153-156 F4.2 Rsun e_R2 [0.02/0.1] R2 uncertainty
158-161 F4.1 Msun M1 [13/22] Primary mass
163-165 F3.1 Msun e_M1 [0.2/2] M1 uncertainty
167-170 F4.1 Msun M2 [5.7/14] Secondary mass
172-174 F3.1 Msun e_M2 [0.4/1] M2 uncertainty
176-186 A11 --- SpT1 MK primary spectral type
188-197 A10 --- SpT2 MK secondary spectral type
199-203 F5.2 mag Mbol1 [-9.6/-4.8] Primary bolometric magnitude
205-208 F4.2 mag e_Mbol1 [0.1/0.6] Mbol1 uncertainty
210-214 F5.2 mag Mbol2 [-7.8/-2.4] Secondary bolometric magnitude
216-219 F4.2 mag e_Mbol2 [0.2/0.7] Mbol2 uncertainty
221-225 F5.2 mag BC1 [-3.6/-2.3] Primary bolometric correction
227-230 F4.2 mag e_BC1 [0.09/0.4] BC1 uncertainty
232-236 F5.2 mag BC2 [-3/-1.4] Secondary bolometric correction
238-241 F4.2 mag e_BC2 [0.1/0.4] BC2 uncertainty
243-247 F5.2 mag MV1 [-6/-2.4] Primary absolute V-band magnitude
249-252 F4.2 mag e_MV1 [0.04/0.3] MV1 uncertainty
254-258 F5.2 mag MV2 [-4.8/-0.9] Secondary absolute V-band magnitude
260-263 F4.2 mag e_MV2 [0.1/0.3] MV2 uncertainty
265-269 F5.2 mag VMag [-6.3/-2.7] Absolute V-band magnitude
271-274 F4.2 mag e_VMag [0.07/0.3] VMag uncertainty
276-279 F4.2 mag Av [5.8/7.1] Adopted extinction
281-284 F4.2 mag e_Av [0.09/0.3] Av uncertainty
286-290 F5.2 mag Vmag [10.3/15] Apparent magnitude of the system
292-295 F4.2 mag e_Vmag [0.01/0.03] Vmag uncertainty
297-299 A3 --- f_Vmag Flag on Vmag (1)
301-305 F5.3 mag rmsV [0.007/0.03] V rms
307-311 F5.3 mag rmsN [0.03/0.05]? NSVS rms
313-316 F4.1 km/s rmsRV1 [10.2/32.9] RV1 rms
318-321 F4.1 km/s rmsRV2 [14.3/37.6] RV2 rms
323-327 F5.2 mag DM [10.6/10.8] Distance modulus
329-332 F4.2 mag e_DM [0.1/0.3] DM uncertainty
334-337 F4.2 kpc Dist [1.3/1.5] Resulting distance
339-342 F4.2 kpc e_Dist [0.07/0.2] Dist uncertainty
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Note (1): Flag as follows:
a = Component A+B only
b = Spot contribution removed
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Global note:
Note (G1): Additional uncertainties at the level of 0.01mag are present as a
result of uncorrected atmospheric transparency variations.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Jan-2016