J/ApJ/850/10 Radial velocities of the F-type EB* V2154 Cygni (Bright+, 2017)
Absolute dimensions of the F-type eclipsing binary V2154 Cygni.
Bright J.C., Torres G.
<Astrophys. J., 850, 10 (2017)>
=2017ApJ...850...10B 2017ApJ...850...10B
ADC_Keywords: Binaries, eclipsing; Radial velocities
Keywords: binaries: eclipsing; stars: evolution; stars: fundamental parameters;
stars: individual (V2154 Cyg) ; techniques: photometric
Abstract:
We report spectroscopic observations of the 2.63day, detached, F-type
main-sequence eclipsing binary V2154 Cyg. We use our observations
together with existing uvby photometric measurements to derive
accurate absolute masses and radii for the stars that are good to
better than 1.5%. We obtain masses of M1=1.269±0.017M☉ and
M2=0.7542±0.0059M☉, radii of R1=1.477±0.012R☉ and
R2=0.7232±0.0091R☉, and effective temperatures of 6770±150K
and 5020±150K for the primary and secondary stars, respectively.
Both components appear to have their rotations synchronized with the
motion in the circular orbit. A comparison of the properties of the
primary with current stellar evolution models gives good agreement for
a metallicity of [Fe/H]=-0.17, which is consistent with photometric
estimates, and an age of about 2.2Gyr. On the other hand, the K2
secondary is larger than predicted for its mass by about 4%. Similar
discrepancies are known to exist for other cool stars, and are
generally ascribed to stellar activity. The system is in fact an X-ray
source, and we argue that the main site of the activity is the
secondary star. Indirect estimates give a strength of about 1kG for
the average surface magnetic field on that star. A previously known
close visual companion to V2154 Cyg is shown to be physically bound,
making the system a hierarchical triple.
Description:
V2154 Cyg was placed on our spectroscopic program in 2001 October, and
observed through 2007 June with two nearly identical echelle
instruments (Digital Speedometer) on the 1.5m telescope at the Oak
Ridge Observatory in the town of Harvard (MA), and on the 1.5m
Tillinghast reflector at the Fred L. Whipple Observatory on Mount
Hopkins (AZ).
The resolving power delivered by these spectrographs was R∼35000, and
the signal-to-noise ratios achieved for the 80 usable observations of
V2154 Cyg range from about 20 to 67 per resolution element of 8.5km/s.
Objects:
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RA (ICRS) DE Designation(s) Per
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21 23 08.30 +48 31 08.1 V2154 Cyg = V* V2154 Cyg (P=2.63063)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 54 80 Heliocentric radial velocity measurements of V2154 Cyg
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See also:
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
I/276 : Tycho Double Star Catalogue (TDSC) (Fabricius+ 2002)
J/ApJS/99/701 : EMSS (Fleming+ 1995)
J/ApJ/469/355 : Teff, B-V and BC relation (Flower, 1996)
J/A+A/363/1081 : Non-linear limb-darkening law for LTE models (Claret, 2000)
J/A+A/372/588 : uvby light curves of V2154 Cyg (Rodriguez+ 2001)
J/AJ/124/1144 : Orbits of 171 single-lined spectrosc. binaries (Latham, 2002)
J/A+A/403/247 : Variability in the ROSAT All-Sky Survey (Fuhrmeister+, 2003)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/A+A/450/681 : Companions to close spectroscopic binaries (Tokovinin+, 2006)
J/A+A/475/677 : X-ray emission from A-type stars (Schroeder+, 2007)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/AJ/139/205 : 2007-2008 WIYN speckle observations of binaries (Horch+, 2010)
J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)
J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)
J/A+A/557/A119 : Eclipsing binary system LL Aquarii (Southworth, 2013)
J/ApJ/780/159 : Rotation-mass-age of old field stars (Epstein+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d HJD Heliocentric Julian Date; HJD-2400000
12- 17 F6.2 km/s RV1 [-53.8/94] Heliocentric radial velocity of star 1
19- 22 F4.2 km/s e_RV1 [0.5/2] Uncertainty in RV1
24- 30 F7.2 km/s RV2 [-107/154] Heliocentric radial velocity of star 2
32- 36 F5.2 km/s e_RV2 [4.5/15.5] Uncertainty in RV2
38- 42 F5.2 km/s RV3 [16/23.1] Heliocentric radial velocity of star 3
44- 47 F4.2 km/s e_RV3 [0.9/3.1] Uncertainty in RV3
49- 54 F6.4 --- Phase Phase (1)
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Note (1): Orbital phases are computed from the reference time of
primary eclipse given in Section 4.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 19-Jun-2018