J/ApJ/904/13 Radial velocity for 10 giant eclipsing binaries (Graczyk+, 2020)
A Distance Determination to the Small Magellanic Cloud with an Accuracy of
Better than Two Percent Based on Late-type Eclipsing Binary Stars.
Graczyk D., Pietrzynski G., Thompson I.B., Gieren W., Zgirski B.,
Villanova S., Gorski M., Wielgorski P., Karczmarek P., Narloch W.,
Pilecki B., Taormina M., Smolec R., Suchomska K., Gallenne A., Nardetto N.,
Storm J., Kudritzki R.-P., Kaluszynski M., Pych W.
<Astrophys. J., 904, 13 (2020)>
=2020ApJ...904...13G 2020ApJ...904...13G
ADC_Keywords: Magellanic Clouds; Stars, double and multiple; Stars, giant;
Spectra, optical; Radial velocities
Keywords: Galaxy distances ; Galaxy structure ; Eclipsing binary stars ;
Stellar distance ; Small Magellanic Cloud ; Late-type giant
stars
Abstract:
We present a new study of late-type eclipsing binary stars in the
Small Magellanic Cloud (SMC) undertaken with the aim of improving the
distance determination to this important galaxy. A sample of 10 new
detached, double-lined eclipsing binaries identified from the OGLE
variable star catalogs and consisting of F- and G-type giant
components has been analyzed. The absolute physical parameters of the
individual components have been measured with a typical accuracy of
better than 3%. All but one of the systems consist of young and
intermediate population stars with masses in the range of 1.4 to
3.8M☉. This new sample has been combined with five SMC eclipsing
binaries previously published by our team. Distances to the binary
systems were calculated using a surface brightness-color calibration.
The targets form an elongated structure, highly inclined to the plane
of the sky. The distance difference between the nearest and
most-distant system amounts to 10kpc with the line-of-sight depth
reaching 7kpc. We find tentative evidence of the existence of a
spherical stellar substructure (core) in the SMC coinciding with its
stellar center, containing about 40% of the young and intermediate age
stars in the galaxy. The radial extension of this substructure is
∼1.5kpc. We derive a distance to the SMC center of
DSMC=62.44±0.47(stat.)±0.81(syst.)kpc corresponding to a
distance modulus (m-M)SMC=18.977±0.016±0.028mag, representing
an accuracy of better than 2%.
Description:
High-resolution echelle spectra were collected with the Magellan
Inamori Kyocera Echelle (MIKE) spectrograph on the Magellan Clay 6.5m
telescope at Las Campanas, the High Accuracy Radial velocity Planet
Searcher (HARPS) spectrograph on the 3.6m telescope at La Silla, and
the Ultraviolet and Visual Echelle Spectrograph (UVES) spectrograph on
the 8.4m Very Large Telescope (VLT) Unit 2 telescope at Paranal. The
MIKE data were obtained with a 5x0.7" slit, yielding a resolution of
about 40000. In the case of HARPS, we used the EGGS mode, giving a
resolution of about R∼80000. UVES was operated in the high-resolution
mode with R∼80000. Integration times were typically 1hour for MIKE and
30minutes for UVES, depending on observing conditions and the
magnitude of the star.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 93 10 Target stars
table2.dat 48 114 The radial velocity measurements
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/288 : IRSF Magellanic Clouds Point Source Catalog (Kato+ 2007)
II/351 : VISTA Magellanic Survey (VMC) catalog (Cioni+, 2011)
VI/120 : High-resolution synthetic stellar library (Coelho+, 2005)
J/AJ/106/2096 : Limb-darkening coefficients in binaries (Van Hamme 1993)
J/ApJ/469/355 : Teff, B-V and BC relation (Flower, 1996)
J/A+A/339/858 : Calibration of stellar parameters (Di Benedetto 1998)
J/AJ/119/1448 : Improved properties for cool stars (Houdashelt+, 2000)
J/AcA/54/1 : OGLE II SMC eclipsing binaries (Wyrzykowski+, 2004)
J/A+A/450/735 : Effective temperatures and radii of stars (Masana+, 2006)
J/AJ/134/1963 : MACHO r,b light curves MC eclipsing binaries (Faccioli+, 2007)
J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)
J/A+A/475/1003 : Stellar parameters of G and K giant stars (Hekker+, 2007)
J/A+A/490/625 : Abundances of NGC 6121 red giants (Marino+, 2008)
J/AJ/135/209 : Rotational & radial veloc 761 HIP giants (Massarotti+, 2008)
J/A+A/497/497 : Physical parameters from JHK flux (Gonzalez-Hernandez+, 2009)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/ApJS/193/1 : UBVRIJHK color-temperature calibration (Worthey+, 2011)
J/AcA/63/323 : OGLE-III SMC eclipsing binary stars (Pawlak+, 2013)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/A+A/557/A119 : Eclipsing binary system LL Aquarii (Southworth, 2013)
J/MNRAS/449/639 : VMC survey. XIV. SFR in SMC (Rubele+, 2015)
J/AcA/66/405 : Galactic bulge eclipsing & ellipsoidal bin (Soszynski+, 2016)
J/ApJS/224/21 : The VMC survey. XIX. Classical Cepheids in SMC (Ripepi+, 2016)
J/ApJ/816/49 : Spitzer/IRAC observations of SMC Cepheids (Scowcroft+, 2016)
J/MNRAS/472/808 : YJKs light curves of SMC Classical Cepheids (Ripepi+, 2017)
J/MNRAS/478/3138 : Luminous cool supergiants Magellanic Clouds (Davies+, 2018)
J/A+A/620/A99 : SMC Cepheids K-band and RV curves (Gieren+, 2018)
J/ApJ/860/1 : Radial velocity measurements of 20 EBs in LMC (Graczyk+, 2018)
J/ApJ/860/1 : Radial velocity measurements of 20 EBs in LMC (Graczyk+, 2018)
J/MNRAS/473/3131 : VMC survey. XXVI. SMC RR Lyrae stars (Muraveva+, 2018)
J/ApJ/887/267 : OB stars embedded in the HI gas of SMC (Murray+, 2019)
J/ApJ/876/85 : HST observations for LMC Cepheids (Riess+, 2019)
J/A+A/640/A2 : Dwarfs & giants surface brightness-colour relat. (Salsi+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- OGLE OGLE identifier (SMC-ECL-NNNN)
6- 19 A14 --- MACHO MACHO identifier
21- 22 I2 h RAh [0] Hour of right ascension (J2000)
24- 25 I2 min RAm [22/57] Minute of right ascension (J2000)
27- 31 F5.2 s RAs Second of right ascension (J2000)
33 A1 --- DE- [-] Sign of declination (J2000)
35- 36 I2 deg DEd [71/73] Degree of declination (J2000)
38- 39 I2 arcmin DEm Arcminute of declination (J2000)
41- 44 F4.1 arcsec DEs Arcsecond of declination (J2000)
46- 51 F6.3 mag Vmag [15.5/18.2] V-band magnitude
53- 58 F6.3 mag Imag [14.8/17.2] I-band magnitude
60- 65 F6.3 mag Jmag [14.2/16.6] J-band magnitude
67- 72 F6.3 mag Kmag [13.8/16] K-band magnitude
74- 81 F8.4 d Per [73.7/317] Orbital period
83- 93 F11.3 d HJD [2452023/2456683] Epoch of th primary minimum
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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- 4 I4 --- OGLE OGLE identifier (SMC-ECL-NNNN)
6- 15 F10.5 d HJD [4784/8842] Heliocentric Julian date JD-2450000
17- 23 F7.3 m/s RVel1 [68.2/216] Radial Velocity of the first component
25- 29 F5.3 m/s e_RVel1 [0.1/1.8] The 1-sigma uncertainty in RVel1
31- 37 F7.3 m/s RVel2 [68.1/224] Radial Velocity of the second component
39- 43 F5.3 m/s e_RVel2 [0.08/0.6] The 1-sigma uncertainty in RVel2
45- 48 A4 --- Instr Spectrograph used; MIKE, HARP ans UVES
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 01-Mar-2022