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J/AJ/115/1856       Dwarf Cepheids in Carina                 (Mateo+, 1998)

Dwarf Cepheids in the Carina dwarf spheroidal galaxy. Mateo M., Hurley-Keller D., Nemec J. <Astron. J. 115, 1856 (1998)> =1998AJ....115.1856M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Photometry, UBV Keywords: galaxies: dwarf - delta Scuti Abstract: We have discovered 20 dwarf Cepheids (DCs) in the Carina dwarf spheroidal galaxy from an analysis of individual CCD images obtained for a deep photometric study of the system. These short-period pulsating variable stars are by far the most distant (∼100kpc) and faintest (V∼23.0) DCs known. The Carina DCs obey a well-defined period-luminosity relation, allowing us to readily distinguish between overtone and fundamental pulsators in nearly every case. Unlike RR Lyrae stars, the pulsation mode turns out to be uncorrelated with light-curve shape, and the overtone pulsators do not tend toward shorter periods compared with the fundamental pulsators. Using the period-luminosity relations from Nemec, Nemec, & Lutz (1994, Cat. J/AJ/108/222 and McNamara (1995AJ....109.1751M), we derive (m-M)0=20.06±0.12, for E(B-V)=0.025 and [Fe/H]=-2.0, in good agreement with recent, independent estimates of the distance/reddening of Carina. The error reflects the uncertainties in the DC distance scale, and in the metallicity and reddening of Carina. The frequency of DCs among upper-main-sequence stars in Carina is approximately 3%. The ratio of dwarf Cepheids to RR Lyrae stars in Carina is 0.13±0.10, though this result is highly sensitive to the star formation history of Carina and the evolution of the horizontal branch. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 71 20 Properties of newly discovered variable stars in Carina v1.dat 27 33 V1 BV photometry v2.dat 27 40 V2 BV photometry v3.dat 27 43 V3 BV photometry v4.dat 27 32 V4 BV photometry v5.dat 27 42 V5 BV photometry v6.dat 27 42 V6 BV photometry v7.dat 27 32 V7 BV photometry v8.dat 27 40 V8 BV photometry v9.dat 27 41 V9 BV photometry v10.dat 27 32 V10 BV photometry v11.dat 27 32 V11 BV photometry v12.dat 27 42 V12 BV photometry v13.dat 27 19 V13 BV photometry v14.dat 27 20 V14 BV photometry v15.dat 27 20 V15 BV photometry v16.dat 27 20 V16 BV photometry v17.dat 27 20 V17 BV photometry v18.dat 27 20 V18 BV photometry v19.dat 27 19 V19 BV photometry v20.dat 27 20 V20 BV photometry
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 3 A3 --- [MHN98] Variable name (V1 to V20), [MHN98] VNN in Simbad 5 I1 --- Field [1/3] Field number 7- 8 I2 h RAh Right ascension (B1950.0) 10- 11 I2 min RAm Right ascension (B1950.0) 13- 16 F4.1 s RAs Right ascension (B1950.0) 18 A1 --- DE- Declination sign (B1950.0) 19- 20 I2 deg DEd Declination (B1950.0) 22- 23 I2 arcmin DEm Declination (B1950.0) 25- 26 I2 arcsec DEs Declination (B1950.0) 28- 32 F5.2 mag <Vmag> Average V magnitude 34- 38 F5.2 mag <Bmag> Average B magnitude 40- 43 F4.2 mag <V>-<B> <V>-<B> colour index 45- 51 F7.5 d Per Period 53- 64 F12.4 d E0 Approximate time of minimum light 66- 69 F4.2 mag DVmag 71 A1 --- Mode [FO?] Mode (1)
Note (1): F: stars pulsating in the fundamental mode O: overtone pulsators ?: cases in which the mode is uncertain
Byte-by-byte Description of file: v*.dat
Bytes Format Units Label Explanations
1 I1 --- Field [1/3] Field number 3 A1 --- Band [BV] Band 5- 16 F12.4 d HJD Heliocentric Julian date 18- 22 F5.2 mag mag Magnitude in Band filter 24- 27 F4.2 mag e_mag rms uncertainty on mag
History: From AJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 09-Mar-1999
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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