J/A+A/363/L1 The distance modulus of the LMC (Kovacs, 2000)
The distance modulus of the Large Magellanic Cloud based on double-mode
RR Lyrae stars.
Kovacs G.
<Astron. Astrophys. 363, L1 (2000)>
=2000A&A...363L...1K 2000A&A...363L...1K
ADC_Keywords: Galaxies, nearby ; Photometry ; Stars, distances ;
Stars, horizontal branch ; Stars, variable ; Surveys
Keywords: stars: fundamental parameters - stars: distances - stars: variables -
stars: oscillations - stars: horizontal-branch -
globular clusters: general - galaxies: Magellanic Clouds
Abstract:
We use double-mode RR Lyrae (RRd) stars from the MACHO variable star
database of the Large Magellanic Cloud (LMC) to estimate its distance,
by utilizing photometric data, linear pulsation and stellar atmosphere
models. If we set E(B-V)=0.11 and [M/H]=-1.5 for LMC, we get
M-m=18.52mag. The fact that the distance moduli obtained in this and
in our former studies of cluster RRd and Small Magellanic Cloud beat
Cepheids agree so well, implies that the only serious source of error
is the zero point of the temperature scale, which should not have
larger than ±0.10mag effect on the distance modulus.
Description:
This table provides periods, intensity averaged V magnitudes and
magnitude averaged V-Rc (Johnson V & Kron-Cousins R) colors of the
MACHO LMC double-mode RR Lyrae variables employed in the above paper.
For the calculation of the averages, an iterative 3-sigma condition
was used to omit outliers. Further references (coordinates, amplitude
ratios, etc.) to these variables can be found in Alcock et al.
(1997ApJ...482...89A 1997ApJ...482...89A) and in Alcock et al. (2000,
Cat. J/ApJ/542/257). Trasformation to the standard system has been
performed in accordance with Alcock et al. (1999PASP..111.1539A 1999PASP..111.1539A).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
lmcrrd.dat 85 181 Double mode RR Lyr stars in LMC
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See also:
J/AJ/114/326 : MACHO Variables V. (Alcock+ 1997)
J/ApJ/542/257 : MACHO Variables IX. (Alcock+ 2000)
http://wwwmacho.mcmaster.ca : MACHO home page
Byte-by-byte Description of file: lmcrrd.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- MACHO MACHO identifier (FFF.NNNNN.NNNN)
18- 25 F8.5 d P0 Period
29- 34 F6.4 --- P1/P0 Period ratio
39- 44 F6.3 mag Vmag Average V magnitude
50- 55 F6.3 mag V-R Average V-Rc color index
61- 64 I4 --- Npoints Number of data points
66- 67 I2 h RAh ? Right ascension (J2000) (1)
69- 70 I2 min RAm ? Right ascension (J2000) (1)
72- 75 F4.1 s RAs ? Right ascension (J2000) (1)
77 A1 --- DE- ? Declination sign (J2000) (1)
78- 79 I2 deg DEd ? Declination (J2000) (1)
81- 82 I2 arcmin DEm ? Declination (J2000) (1)
84- 85 I2 arcsec DEs ? Declination (J2000) (1)
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Note (1): Positions added at CDS from Alcock et al., 1997ApJ...482...89A 1997ApJ...482...89A
and 2000, Cat. J/ApJ/542/257.
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Acknowledgements: Geza Kovacs
(End) Geza Kovacs [Konkoly Observatory], Patricia Bauer [CDS] 07-Dec-2000