J/ApJ/652/313 BV phot. of a detached eclipsing binary in M 33 (Bonanos+, 2006)
The first DIRECT distance determination to a detached eclipsing binary in M 33.
Bonanos A.Z., Stanek K.Z., Kudritzki R.P., Macri L.M., Sasselov D.D.,
Kaluzny J., Stetson P.B., Bersier D., Bresolin F., Matheson T.,
Mochejska B.J., Przybilla N., Szentgyorgyi A.H., Tonry J., Torres G.
<Astrophys. J., 652, 313-322 (2006)>
=2006ApJ...652..313B 2006ApJ...652..313B
ADC_Keywords: Galaxies, nearby ; Binaries, eclipsing ; Photometry
Keywords: binaries: eclipsing - binaries: spectroscopic - distance scale -
galaxies: individual (M33) - stars: fundamental parameters
Abstract:
We present the first direct distance determination to a detached
eclipsing binary in M33, which was found by the DIRECT Project.
Located in the OB 66 association at coordinates
(RA,DE)=(01:33:46.17,+30:44:39.9) for J2000.0, it was one of the most
suitable detached eclipsing binaries found by DIRECT for distance
determination, given its apparent magnitude and orbital period. We
obtained follow-up BV time-series photometry, JHKs photometry, and
optical spectroscopy from which we determined the parameters of the
system. It contains two O7 main-sequence stars, with masses of
33.4±3.5 and 30.0±3.3M☉ and radii of 12.3±0.4 and
8.8±0.3R☉, respectively. We derive temperatures of
37000±1500 and 35600±1500K. Using BVRJHKs photometry for the flux
calibration, we obtain a distance modulus of 24.92±0.12mag
(964±54kpc), which is 0.3mag longer than the Key Project distance
to M33. We discuss the implications of our result and the importance
of establishing M33 as an independent rung on the cosmological
distance ladder.
Description:
In 1999 and 2001 we obtained follow-up photometry with the Tektronix
2048x2048 CCD (T2KA camera) at the Kitt Peak National Observatory
(KPNO) 2.1m telescope, with a pixel scale of 0.305"/pixel. The 1999
observations are described in Paper VII (Cat. J/AJ/121/2032). In
addition we obtained 94x600s exposures in the V band and 19x600s in B
band in 2001 October.
Objects:
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RA (2000) DE Designation(s)
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01 33 46.17 +30 44 39.9 DEB = D33 J013346.2+304439.9
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 25 278 V-Band Light Curve
table2.dat 25 83 B-Band Light Curve
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See also:
J/AJ/115/1016 : M31B eclipsing binaries and Cepheids (Kaluzny+ 1998)
J/AJ/115/1894 : M31A eclipsing binaries and Cepheids (Stanek+ 1998)
J/AJ/117/2810 : Eclipsing binaries and Cepheids in M31C (Stanek+, 1999)
J/AJ/118/346 : M31D eclipsing binaries and Cepheids (Kaluzny+ 1999)
J/AJ/118/2211 : M31F eclipsing binaries and Cepheids (Mochejska+ 1999)
J/AJ/121/861 : BVI photometry of central part of M33 (Macri+, 2001)
J/AJ/121/870 : BVI photometry of Variables in M33 (Macri+, 2001)
J/AJ/121/2032 : Direct variables in M33A field (Mochejska+, 2001)
J/AJ/122/1383 : DIRECT BVI photometry in M31 (Mochejska+, 2001)
J/AJ/122/2477 : DIRECT variables in M33B field (Mochejska+, 2001)
J/AJ/126/175 : M31Y eclipsing binaries and Cepheids (Bonanos+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian Date
14- 19 F6.3 mag Vmag The V band magnitude
21- 25 F5.3 mag e_Vmag Error in Vmag
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d HJD Heliocentric Julian Date
14- 19 F6.3 mag Bmag The B band magnitude
21- 25 F5.3 mag e_Bmag Error in Bmag
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History:
From electronic version of the journal
References:
Kaluzny et al., Paper I 1998AJ....115.1016K 1998AJ....115.1016K, Cat. J/AJ/115/1016
Stanek et al., Paper II 1998AJ....115.1894S 1998AJ....115.1894S, Cat. J/AJ/115/1894
Stanek et al., Paper III 1999AJ....117.2810S 1999AJ....117.2810S, Cat. J/AJ/117/2810
Kaluzny et al., Paper IV 1999AJ....118..346K 1999AJ....118..346K, Cat. J/AJ/118/346
Mochejska et al., Paper V 1999AJ....118.2211M 1999AJ....118.2211M, Cat. J/AJ/118/2211
Macri et al., Paper VI 2001AJ....121..870M 2001AJ....121..870M, Cat. J/AJ/121/870
Mochejska et al., Paper VII 2001AJ....121.2032M 2001AJ....121.2032M, Cat. J/AJ/121/2032
Mochejska et al., Paper VIII 2001AJ....122.2477M 2001AJ....122.2477M, Cat. J/AJ/122/2477
Bonanos et al., Paper Ix 2003AJ....126..175B 2003AJ....126..175B, Cat. J/AJ/126/175
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 25-Jul-2008