J/ApJ/835/251 Radial velocities and BVIc LCs of the EB* CU Cnc (Wilson+, 2017)
The M dwarf eclipsing binary CU Cancri.
Wilson R.E., Pilachowski C.A., Terrell D.
<Astrophys. J., 835, 251-251 (2017)>
=2017ApJ...835..251W 2017ApJ...835..251W (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Radial velocities ; Photometry, VRI
Keywords: binaries: eclipsing; binaries: spectroscopic;
stars: individual: CU Cnc
Abstract:
Spectral features, radial velocities, elemental abundance estimates,
other spectral data, and BVIC light curves are reported for the
double-M dwarf eclipsing binary CU Cancri-a good target for a radius
check versus the Zero Age Main Sequence (ZAMS) due to the low
component masses and corresponding very slow evolutionary expansion.
The estimate of [Fe/H] is about 0.4, although continuum placement and
other difficulties due to line crowding introduce the usual
uncertainties for red dwarfs. Detection of the LiIλ6707 line
was attempted, with an estimated upper limit of 50mÅ. Spectral and
photometric indicators of stellar activity are described and
illustrated. Other objectives were to measure the stellar radii via
simultaneous velocity and light-curve solutions of earlier and new
data while also improving the ephemeris by filling gaps in timewise
coverage with the new velocities and eclipse data from the new light
curves. The radii from our solutions agree within about 2% with those
from Ribas, being slightly larger than expected for most estimates of
the ZAMS. Some aspects of the red dwarf radius anomaly are briefly
discussed. Evolution tracks show only very slight age-related
expansion for masses near those in CU Cnc. Such expansion could be
significant if CU Cnc were similar in age to the Galaxy, but then its
Galactic velocity components should be representative of Population
II, and they are not.
Description:
Infrared spectra of CU Cnc were obtained with the Phoenix spectrometer
on the 2.1 and 4m telescopes at Kitt Peak National Observatory in 2013
December, and 2014 January and February (λc=2.33um, R=50000).
The primary star is defined here as the slightly hotter and more
massive one that is eclipsed near zero phase according to the
ephemeris.
High-resolution optical spectra of CU Cnc were obtained for estimation
of elemental abundances. An 1800s observation was obtained on 2014 May
17 with the Astrophysical Research Consortium (ARC) echelle
spectrograph (ARCES) at a phase near quadrature. A second spectrum was
obtained with the same instrument on 2015 November 21 with an exposure
time of 3600s at a phase near conjunction. The spectra cover the
wavelength range from 3500 to 10000Å and resolving power is about
31500.
The CU Cnc field was observed at the Sonoita Research Observatory with
Johnson-Cousins BVIC and SDSS g'r'i' filters.
Objects:
------------------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
------------------------------------------------------------------------
08 31 37.57 +19 23 39.4 V* CU Cnc = WDS J08317+1924A (P=2.771470)
------------------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 38 48 Radial velocity observations with
the Phoenix Spectrometer
table3.dat 59 823 *Light curves in B, V , and IC bands
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Note on table3.dat: CU Cnc aperture photometry was done in IRAF, with the BVIC
differential magnitudes against GSC 1387-01006 extending
from JD 2457006 to 2457081. See section 3 for further explanations.
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2014)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/A+A/398/239 : RI differential photometry of CU Cnc (Ribas, 2003)
J/ApJ/628/411 : Identification & analysis of eclipsing binaries (Devor+, 2005)
J/AJ/130/873 : Properties of BQS objects in the SDSS DR3 area (Jester+, 2005)
J/MNRAS/406/2559 : BVRI light curves of GSC2314-0530 (Dimitrov+, 2010)
J/ApJ/709/535 : Masses and radii of eclipsing binaries (Brown, 2010)
J/ApJ/723/1469 : Flux calibrations and WZ Oph photometry (Wilson+, 2010)
J/AJ/141/78 : Low-mass eclipsing binaries in KIC (Coughlin+, 2011)
J/MNRAS/431/3240 : Ji photometry of WTS 19g-4-02069 (Nefs+, 2013)
J/A+A/572/A50 : J0113+31 light + velocity curves (Gomez Maqueo Chew+, 2014)
J/ApJ/789/102 : Properties of late M-dwarfs (Janson+, 2014)
J/MNRAS/442/2620 : VRI light curve of 5 eclipsing binaries (Zhang+, 2014)
J/MNRAS/437/2831 : 4 transiting F-M binary systems (Zhou+, 2014)
J/other/PASA/31.24 : Milky Way detached double-lined EB catalog (Eker+, 2014)
J/AJ/149/131 : Param. of galactic nearby main-sequence stars (Eker+, 2015)
J/AJ/152/180 : Bolometric fluxes of EB* in Tycho-2 (Stassun+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.5 d HJD Midpoint Heliocentric Julian date; HJD-2450000
13- 15 I3 s Exp [600/900] Integration time
17- 22 F6.2 km/s RV1 [-55/72] Radial velocity of the Primary
24- 29 F6.2 km/s RV2 [-71/68] Radial velocity of the Secondary
31- 34 F4.1 --- R [3/19] Tonry-Davis (1979AJ.....84.1511T 1979AJ.....84.1511T)
"R" value (1)
36- 38 F3.1 km/s sig [0.5/1.4]? Standard deviation of the four
independent measurements
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Note (1): The R value is the height of the cross-correlation peak divided by
the noise in the cross-correlation function. Observations with
R's above three are ordinarily considered reliable.
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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- 12 F12.4 d HJD-B ?=0 Heliocentric Julian Date of B band
observation
14- 19 F6.3 mag delBmag [-0.6/0.4]?=0 Differential B band magnitude
21- 32 F12.4 d HJD-V Heliocentric Julian Date of V band observation
34- 39 F6.3 mag delVmag [-0.9/-0.4] Differential V band magnitude
41- 52 F12.4 d HJD-Ic ?=0 Heliocentric Julian Date of Ic band
observation
54- 59 F6.3 mag delIcmag [-2.8/-2.5]?=0 Differential Ic band magnitude
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Sep-2017