J/AJ/155/109 Young binaries in Ophiuchus&Upper Centaurus-Lupus (Schaefer+, 2018)
Orbital motion of young binaries in Ophiuchus and Upper Centaurus-Lupus.
Schaefer G.H., Prato L., Simon M.
<Astron. J., 155, 109 (2018)>
=2018AJ....155..109S 2018AJ....155..109S (SIMBAD/NED BibCode)
ADC_Keywords: Star Forming Region ; Associations, stellar ;
Stars, double and multiple ; Stars, pre-main sequence ;
Stars, distances ; Spectral types ; Photometry, infrared
Keywords: binaries: visual - stars: fundamental parameters -
stars: pre-main sequence
Abstract:
We present measurements of the orbital positions and flux ratios of
17 binary and triple systems in the Ophiuchus star-forming region and
the Upper Centaurus-Lupus cluster based on adaptive optics imaging at
the Keck Observatory. We report the detection of visual companions in
MML 50 and MML 53 for the first time, as well as the possible detection
of a third component in WSB 21. For six systems in our sample, our
measurements provide a second orbital position following their initial
discoveries over a decade ago. For eight systems with sufficient orbital
coverage, we analyze the range of orbital solutions that fit the data.
Ultimately, these observations will help provide the groundwork toward
measuring precise masses for these pre-main-sequence stars and
understanding the distribution of orbital parameters in young multiple
systems.
Description:
Based on our adaptive optics (AO) observations and previous measurements
available in the literature, we provide an overview on the status of
the orbital motion and analysis for each binary and triple system that
was observed. We also indicate which systems show variability in their
flux ratios. We observed the sample of binary stars using the near-infrared
camera NIRC2 (Wizinowich et al. 2000SPIE.4007....2W 2000SPIE.4007....2W) on the 10 m Keck II
Telescope at the W. M. Keck Observatory. We used the natural guide star
AO system on all nights except for UT 2015 April 5 when we used the laser
guide star. MML 50 and MML 53 were observed using natural guide star AO
on all nights (including UT 2015 April 5). All images were taken with
the narrow-field camera in NIRC2, which has a field of view of 10".
Objects:
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RA (ICRS) DE Designation(s)
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16 28 06 -24 32.5 Ophiuchus = NAME Ophiuchus Cloud
15 24 -41.9 Upper Centaurus-Lupus = NAME Upper Centaurus Lupus
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 70 19 Observed Multiple Systems
table2.dat 96 46 Log of Keck NIRC2 AO Observations
table3.dat 87 167 Keck NIRC2 Adaptive Optics Measurements of
the Orbital Positions in Multiple Systems
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See also:
J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)
J/AJ/124/1670 : Post-T Tauri Stars in Sco-Cen Association (Mamajek+, 2002)
J/ApJ/593/1093 : IC 348 membership (Luhman+, 2003)
J/AJ/130/1733 : Optical spectroscopy of ρ Oph stars (Wilking+, 2005)
J/ApJ/630/381 : Mid-IR imaging in ρ Oph (Barsony+, 2005)
J/A+A/452/245 : Near-IR photometry of PMS stars in rho Oph (Natta+, 2006)
J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006)
J/A+A/485/155 : HK photometry of rho Oph PMS stars (Alves de Oliveira+, 2008)
J/ApJ/712/925 : Transition circumstellar disks in Ophiuchus (Cieza+, 2010)
J/AJ/142/140 : Optical spectroscopy of ρ Oph stars. II. (Erickson+, 2011)
J/ApJ/813/83 : Multiple star formation in Ophiuchus (Cheetham+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Object name
10- 19 A10 --- OName Other object name
21- 22 I2 h RAh Hour of Right Ascension (J2000)
24- 25 I2 min RAm Minute of Right Ascension (J2000)
27- 32 F6.3 s RAs Second of Right Ascension (J2000)
34- 34 A1 --- DE- Sign of the Declination (J2000)
35- 36 I2 deg DEd Degree of Declination (J2000)
38- 39 I2 arcmin DEm Arcminute of Declination (J2000)
41- 45 F5.2 arcsec DEs Arcsecond of Declination (J2000)
47- 51 F5.1 pc Dist [130/147.3] Distance
53- 58 A6 --- Region Region identifier
60- 64 A5 --- SpType MK spectral type
66- 67 A2 --- r_SpType Reference for SpType (1)
69- 70 A2 --- r_Dist Reference for Dist (2)
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Note (1): Reference for spectral type as follows:
S1 = Mamajek et al. (2002, J/AJ/124/1670);
S2 = Erickson et al. (2011, J/AJ/142/140);
S3 = Prato et al. (2018AAS...23133912P);
S4 = Torres et al. (2006, J/A+A/460/695);
S5 = Bouvier & Appenzeller (1992A&AS...92..481B 1992A&AS...92..481B);
S6 = Wilking et al. (2005, J/AJ/130/1733);
S7 = Luhman et al. (2003, J/ApJ/593/1093);
S8 = Cieza et al. (2010, J/ApJ/712/925).
Note (2): Reference for distance as follows:
D1 = de Zeeuw et al. (1999, J/AJ/117/354);
D2 = Cheetham et al. (2015, J/ApJ/813/83);
D3 = Ortiz-Leon et al. (2017ApJ...834..141O 2017ApJ...834..141O).
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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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1-11 A11 "date" Date UT date of observation
13- 17 I5 "h:m" Time UT time of observation
19- 27 A9 --- Name Object name
29- 34 A6 --- OName Other object name
36- 40 A5 --- Filt1 First filter used
42- 43 I2 --- o_Filt1 [3/30] Number of images taken in Filt1
45- 49 A5 --- Filt2 Second filter used
51- 52 I2 --- o_Filt2 [3/12]? Number of images taken in Filt2
54- 58 A5 --- Filt3 Third filter used
60- 61 I2 --- o_Filt3 [6/12]? Number of images taken in Filt3
63- 64 A2 --- Filt4 Fourth filter used
66- 67 I2 --- o_Filt4 [3/20]? Number of images taken in Filt4
69- 71 I3 Hz AORate [50/750] Adaptive optics (AO) rate
73- 76 F4.2 s Tmin [0.18/4] Minimum integration time (1)
78- 80 F3.1 s Tmax [0.5/2]? Maximum integration time (1)
82- 96 A15 --- PSF Point-spread function (PSF) used
(ePSF="effective PSF")
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Note (1): Integration time per co-add. Each image is composed of 10 co-added
exposures. If different exposure times were used for different sets of images,
then the range of values is listed (Tmin, Tmax).
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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 A9 --- Name Object name
11- 20 A10 --- OName Other object name
22- 26 A5 --- m_Name Component identification (1)
28- 36 F9.4 yr JYr [2003.2855/2015.5261] Julian year
38- 44 F7.2 mas Sep [21.47/5071.4]? Binary separation
46- 50 F5.2 mas e_Sep [0.12/10.28]? Error in Sep
52- 58 F7.3 deg PA [9.99/352.96]? Position angle
60- 64 F5.3 deg e_PA [0.025/5.8]? Error in PA
66- 70 A5 --- Filt Filter
72- 77 F6.4 --- Fratio [0.0335/5.527] Flux ratio (f2/f1)
79- 84 F6.4 --- e_Fratio [0.0009/0.532] Error in Fratio
86- 87 A2 --- Note Code for additional note (2)
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Note (1): Component designation "X,Y" indicates that component Y was measured
relative to X.
Note (2): Code for additional note as follows:
N1 = ROX 47 Ac,Aa and Ac,Ab give the position angle of the brighter component
relative to the fainter tertiary. This angle is flipped 180 ° from
the position angle given in the literature for the faint companion
relative to the brighter primary;
N2 = System is fit as a binary, assuming the close pair is unresolved;
N3 = System is fit as a possible triple. The close pair separation is small
so the results need confirmation;
N4 = H-band images of VSSG 14 from UT 2014 Jul 5 (2014.5075) were of poor
quality and not included in the final results. The discrepancy between
the two positions measured in 2014.5 is likely because of a larger
mismatch of PSF shapes on UT 2014 Jul 5. The components of VSSG 14 were
too blended to create an effective PSF.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 24-Oct-2018