J/AJ/132/1910 HD 131861 radial velocities and VRI light curves (Fekel+, 2006)
HD 131861, a double-line spectroscopic triple system.
Fekel F.C., Henry G.W., Barlow D.J., Pourbaix D.
<Astron. J., 132, 1910-1917 (2006)>
=2006AJ....132.1910F 2006AJ....132.1910F
ADC_Keywords: Stars, double and multiple ; Radial velocities ; Photometry, VRI
Keywords: binaries: eclipsing - binaries: spectroscopic -
stars: fundamental parameters
Abstract:
Our red-wavelength spectroscopic observations of HD 131861, a
previously known single-line multiple system, span 20 years. Now lines
of two components, the short-period F5 V primary and G8 V secondary,
have been detected. The inner orbit is circular with a period of
3.5507439-days, while the outer orbit of the system has a period of
1642 days or 4.496-yr and a relatively low eccentricity of 0.10.
Analysis of the Hipparcos data produces a well-determined astrometric
orbit for the long-period system that has an inclination of 52°. Our
photometric observations show shallow primary and secondary eclipses
of the short-period pair, and eclipse solutions result in an
inclination of 81°. Thus, the long- and short-period orbits are not
coplanar. The mass of the unseen third component is 0.7M{dot},
corresponding to a mid-K dwarf. The total mass of the system,
3.08M{dot}, leads to a semimajor axis of 4AU for the outer orbit.
The F5 V primary is rotating more slowly than it would if it were
synchronously rotating, while the G8 V secondary may be synchronously
rotating. The lithium abundance of the F5 V primary is similar to the
initial lithium abundance found for Population I dwarfs and so
indicates no significant dilution.
Description:
From 1984 March through 2005 June we obtained 64 spectrograms of
HD 131861 at the Kitt Peak National Observatory (KPNO) with the coude
feed telescope, coude spectrograph, and a Texas Instruments CCD
detector. The first seven observations, obtained from 1984 through
1987, used grating D, which resulted in a wavelength range of about
90Å and a resolution of 0.23Å. One spectrogram was centered at
6700Å, while all the rest were obtained at 6430Å. From 1988
onward grating A was used, which produced spectrograms with a
wavelength range of over 80Å and a resolution of 0.21Å. The vast
majority of the grating A observations were centered at 6430Å,
while four were obtained at 6700Å.
Objects:
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RA (2000) DE Designation(s) (star)
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14 54 24.5 +45 17 55.7 HD 131861 = HIP 72939 (variable)
14 44 28.2 +45 11 09.6 HD 130044 = HIP 72066 (comparison)
14 49 18.7 +46 06 58.4 HD 130945 = HIP 72487 (check)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 53 87 Radial velocities of HD 131861
table2.dat 54 2113 Photometric observations of HD 131861
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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- 11 F11.3 d HJD Heliocentric Julian date
12 A1 --- n_HJD [b] b: Lithium region (λ=6700Å)
14- 18 F5.3 --- phiL [0/1] Phase in the long-period orbit
20- 24 F5.3 --- phiS ]0/1[ Phase in the short-period orbit
26- 30 F5.1 km/s RVAa Aa component radial velocity
32- 35 F4.1 km/s (O-C)Aa Aa component observed minus Computer
radial velocity
37- 42 F6.1 km/s RVAb ?=- Ab component radial velocity
43 A1 --- n_RVAb [a] a: 3σ residual, velocity
given zero weight.
44- 47 F4.1 km/s (O-C)Ab ?=- Ab component Observed minus Computer
radial velocity
50- 53 A4 --- Obs Onservatory (HPO or KPNO)
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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- 12 F12.4 --- HJD Heliocentric Julian Date
14- 19 F6.3 mag DV(V-C) ?=99.999 Var-Comp differential V magnitude (1)
21- 26 F6.3 mag DR(V-C) ?=99.999 Var-Comp differential R magnitude (1)
28- 33 F6.3 mag DI(V-C) ?=99.999 Var-Comp differential I magnitude (1)
35- 40 F6.3 mag DV(Ck-C) ?=99.999 Check-Comp differential V magnitude (1)
42- 47 F6.3 mag DR(Ck-C) ?=99.999 Check-Comp differential R magnitude (1)
49- 54 F6.3 mag DI(Ck-C) ?=99.999 Check-Comp differential I magnitude (1)
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Note (1): The '99.999' signifies that the differential magnitude was
discarded because its internal standard deviation exceeded 0.02mag.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 24-Jul-2008