J/AJ/120/284 Variables in Leo II dwarf spheroidal (Siegel+, 2000)
Exploring the Leo II dwarf spheroidal galaxy. I. The variable star content.
Siegel M.H., Majewski S.R.
<Astron. J. 120, 284 (2000)>
=2000AJ....120..284S 2000AJ....120..284S
ADC_Keywords: Stars, variable ; Photometry ; Regional catalog
Keywords: galaxies: dwarf - galaxies: individual (Leo II) -
galaxies: stellar content - stars: variables: general
Abstract:
We present the first comprehensive catalog of variable stars in the
Leo II dwarf spheroidal galaxy. We have identified 148 RR Lyrae type
variables, of which 140 were amenable to derivation of variability
parameters with our data. We have also confirmed the existence of four
anomalous Cepheids as identified in previous studies. The average
period of the RR Lyrae ab variables (0.62 days), the fraction of c
variables (0.24), and the minimum period of the RR Lyrae ab variables
(0.51 days) all define Leo II as an "Oosterhoff intermediate" galaxy.
We have used the properties of these variables to derive a metallicity
for Leo II of approximately [Fe/H]=-1.9.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 148 RR Lyrae variables
table2.dat 88 4 Anomalous Cepheids
table4.dat 42 7830 Julian dates and magnitudes
table5.dat 13 20 Dickens & Irwin (1993, Cat. J/MNRAS/261/657)
stars that are nonvariable
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See also:
J/MNRAS/261/657 : Deep CCD photometry of Leo II (Demers+ 1993)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- VName Variable designation (VNNN),
[SM2000] VNNN in Simbad
6- 9 I4 --- [SM2000] Star identification number,
[SM2000] NNNN in Simbad
11- 18 F8.3 pix Xpos X position
20- 27 F8.3 pix Ypos Y position
29- 30 I2 h RAh Right ascension (J2000.0)
32- 33 I2 min RAm Right ascension (J2000.0)
35- 39 F5.2 s RAs Right ascension (J2000.0)
41 A1 --- DE- Declination sign (J2000.0)
42- 43 I2 deg DEd Declination (J2000.0)
45- 46 I2 arcmin DEm Declination (J2000.0)
48- 51 F4.1 arcsec DEs Declination (J2000.0)
53- 59 F7.5 d Per ? Period
61- 65 F5.3 mag AVmag ? Amplitude in the V passband
67- 71 F5.2 mag Vmag V magnitude
73- 76 A4 --- Type Bailey (1902AnHar..38....1B 1902AnHar..38....1B) type
(ab, abb, c or Unk.)
78- 83 F6.3 --- dlogPer ? Pediod shift, ΔlogP (1)
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Note (1): Period shift is measured by comparison with a reference variable
population. The usual candidate population is that of M3, for which
Sandage (1982ApJ...252..553S 1982ApJ...252..553S, 1982ApJ...252..574S 1982ApJ...252..574S) derived a measure
of ΔlogP=-(0.129AB+ 0.088 + log P),
where AB is the amplitude in the B passband.
The resulting revised period shift relations are
ΔlogP=-(0.129AB + 0.112 + logP),
ΔlogP=-(0.156AV + 0.112 + logP).
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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 A4 --- VName Variable designation (VNNN)
6- 9 I4 --- [SM2000] Star identification number
11- 18 F8.3 pix Xpos X position
20- 27 F8.3 pix Ypos Y position
29- 30 I2 h RAh Right ascension (J2000.0)
32- 33 I2 min RAm Right ascension (J2000.0)
35- 39 F5.2 s RAs Right ascension (J2000.0)
41 A1 --- DE- Declination sign (J2000.0)
42- 43 I2 deg DEd Declination (J2000.0)
45- 46 I2 arcmin DEm Declination (J2000.0)
48- 51 F4.1 arcsec DEs Declination (J2000.0)
53- 59 F7.5 d Per ? Period
61- 65 F5.3 mag AVmag ? Amplitude in the V passband
67- 71 F5.2 mag Vmag V magnitude
73- 83 A11 --- Mode Pulsation mode
85- 88 A4 --- Swope Swope (1968, AJ, 73, S204) variable number
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [SM2000] Star identification number
8- 19 F12.4 d JD Julian Date
23- 30 F8.5 mag Vmag V band magnitude
34- 40 F7.5 mag e_Vmag Uncertainty in Vmag
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- [DI93] DI93 designation (VNNN), in J/MNRAS/261/657,
[DI93] NNNN in Simbad
6- 9 I4 --- [SM2000] Star identification number
11- 13 F3.1 --- W-S Welch-Stetson (1993AJ....105.1813W 1993AJ....105.1813W)
variability index
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History: From AJ electronic version
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 29-Aug-2000