J/AJ/128/1748 VR photometry of type II Cepheids (Schmidt+, 2004)
Photometry of type II Cepheids. I. The long-period stars.
Schmidt E.G., Johnston D., Langan S., Lee K.M.
<Astron. J., 128, 1748-1760 (2004)>
=2004AJ....128.1748S 2004AJ....128.1748S
ADC_Keywords: Stars, population II ; Stars, variable ; Photometry
Keywords: Cepheids - stars: Population II
Abstract:
We present 1256 new photometric observations of 36 Cepheids with
periods longer than 8 days. The majority are likely type II Cepheids,
but we have included about a dozen classical Cepheids for comparison
purposes, a few stars of uncertain type, and one putative RV Tauri
star. We discuss the appearance of the light curves, the Fourier
parameters, and the light-curve stability in terms of differentiation
between type I and type II Cepheids. Although we encounter the same
difficulties as previous investigators in using these parameters for
this purpose, we are able to identify some stars of particular
interest, including several likely type I Cepheids at large distances
from the Galactic plane. Six stars with especially large period
changes are identified and discussed.
Description:
The observations were made at Behlen Observatory with the 0.76m
telescope. Three different CCDs were used in the observations
presented here: prior to 1999 May (JD2,451,300) a Photometrics TI4849
CCD system; between 2000 January (JD2,450,480) and 2002 March
(JD2,452,344) a Santa Barbara Instruments ST-7 CCD; after 2002 April
(JD2,452,380) a Princeton Instruments VersArray:1300B CCD.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 84 45 The program stars
table2.dat 44 1256 Photometric data
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See also:
II/217 : Photoelectric observations of Cepheids in UBV(RI)c
(Berdnikov, 1997)
J/AJ/112/2769 : Behlen Observatory Survey. IV. (Schmidt+ 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Name
10 A1 --- f_Name Flag on Name (1)
11- 14 F4.1 d Per ? Period
17- 21 A5 --- Class GCVS class (Cat. II/250)
24- 25 A2 --- Class2 [II] Cepheid Harris class (1985AJ.....90..756H 1985AJ.....90..756H)
28 I1 --- Ncomp Number of comparison stars used for each field
31- 32 I2 mmag sigVmag ? Standard errors of the adopted V magnitude
of the comparison stars
35- 36 I2 mmag sigRmag ? Standard errors of the adopted R magnitude
of the comparison stars
39- 40 I2 --- Nnights ? Number of photometric nights included in
calculating the comparison star magnitudes
41 A1 --- Note Note (2)
43- 49 I7 d Date1 Julian date of start of observation
50 A1 --- --- [-]
51- 57 I7 d Date2 Julian date of end of observation
60- 62 I3 --- Ntot ? Total number of light-curve points used
63 A1 --- --- [(]
64- 65 I2 --- Nnew New points in the light-curve
66 A1 --- --- [)]
68- 84 A17 --- Ref ? References to the sources of the photometry (3)
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Note (1): "a" means that IX Cas is a member of a single-line spectroscopic
binary (Harris & Welch, 1989AJ.....98..981H 1989AJ.....98..981H).
Note (2): Note is defined as follows:
b = The V magnitudes from the present photometry differed systematically
from the earlier photometry. Accordingly, their zero point was adjusted
to produce agreement with the earlier photometry.
c = No photometric nights are available. The zero point is set to make mean
of variable equal that from later photometry.
Note (3): Reference numbers have the following meaning:
1 = New Behlen Observatory photometry;
2 = Pel, 1976A&AS...24..413P 1976A&AS...24..413P (Walraven photometry transformed to the
Johnson system using VJ=6.874-2.5[VW-0.065(VW-BW)] from the
same reference);
3 = Harris, 1980, Ph.D. thesis, Univ. Washington;
4 = Szabados 1980CoKon..76....1S 1980CoKon..76....1S, 1981CoKon..77....1S 1981CoKon..77....1S;
5 = Berdnikov 1986PZ.....22..369B 1986PZ.....22..369B, 1987PZ.....22..530B 1987PZ.....22..530B, 1992PAZh...18..325B 1992PAZh...18..325B,
1993PAZh...19..210B 1993PAZh...19..210B, 1993PZ.....23...64B 1993PZ.....23...64B,
1992, Astron. Astrophys. Trans., 2, 1;31;43;107;157;
6 = Schmidt & Seth, 1996, Cat. J/AJ/112/2769;
7 = Berdnikov & Yakubov, 1993PZ.....23...47B 1993PZ.....23...47B;
8 = Moffett & Barnes, 1984ApJS...55..389M 1984ApJS...55..389M;
9 = Berdnikov & Turner, 1995PAZh...21..803B 1995PAZh...21..803B;
10 = Berdnikov & Voziakova, 1995PAZh...21..348B 1995PAZh...21..348B;
11 = Schmidt et al., 1995AJ....109.1239S 1995AJ....109.1239S.
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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- 9 A9 --- Name Object name
10- 20 F11.3 d HJD Heliocentric Julian Date
23- 28 F6.3 mag Vmag The V-band magnitude
31- 36 F6.3 mag Rmag The R-band magnitude
40- 44 F5.3 mag V-R The (V-R) color
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 08-Apr-2005