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J/AJ/115/1894 Eclipsing binaries and Cepheids in M31A field (Stanek+ 1998)
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DIRECT distances to nearby galaxies using detached eclipsing binaries and
Cepheids. II. Variables in the field M31A.
Stanek K.Z., Kaluzny J., Krockenberger M., Sasselov D.D., Tonry J.L.,
Mateo M.
<Astron. J. 115, 1894 (1998)>
=1998AJ....115.1894S (SIMBAD/NED BibCode)
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ADC_Keywords: Stars, variable ; Binaries, eclipsing ; Photometry, UBVRI ;
Stars, diameters
Keywords: binaries: eclipsing - Cepheids - distance scale -
galaxies: individual (M31) - stars: variables: other
Abstract:
We have undertaken a long-term project, DIRECT, to obtain the direct
distances to two important galaxies in the cosmological distance
ladder, M31 and M33, using detached eclipsing binaries (DEBs) and
Cepheids. While rare and difficult to detect, DEBs provide us with the
potential to determine these distances with an accuracy better than
5%. The extensive photometry obtained in order to detect DEBs provides
us with good light curves for the Cepheid variables. These are
essential to the parallel project to derive direct Baade-Wesselink
distances to Cepheids in M31 and M33. For both Cepheids and eclipsing
binaries, the distance estimates will be free of any intermediate
steps. As a first step in the DIRECT project, between 1996 September
and 1997 January we obtained 36 full nights on the
Michigan-Dartmouth-MIT Observatory 1.3m telescope and 45 full/partial
nights on the F. L. Whipple Observatory 1.2m telescope to search for
DEBs and new Cepheids in the M31 and M33 galaxies. In this paper,
second in a series, we present the catalog of variable stars, most of
them newly detected, found in the field M31A
[({alpha},{delta})=(11.34{deg}, 41.73{deg}), J2000.0]. We have found
75 variable stars: 15 eclipsing binaries, 43 Cepheids, and 17 other
periodic, possible long-period or nonperiodic variables. The catalog
of variables, as well as their photometry and finding charts, is
available via anonymous ftp and the World Wide Web. The CCD frames are
available upon request.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 74 15 DIRECT eclipsing binaries in M31A
table2.dat 61 43 DIRECT Cepheids in M31A
table3.dat 62 6 DIRECT other periodic variables in M31A
table4.dat 65 11 DIRECT miscellaneous variables in M31A
table5.dat 33 2019 Light curves of eclipsing binaries in M31A
table6.dat 33 6397 Light curves of Cepheids in M31A
table7.dat 33 840 Light curves of other periodic variables in M31A
table8.dat 33 1624 Light curves of miscellaneous variables in M31A
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See also:
J/AJ/115/1016 : Paper I. (M31B field). (Kaluzny+ 1998)
J/AJ/117/2810 : M31C eclipsing binaries and Cepheids (Stanek+, 1999)
J/AJ/118/346 : M31D eclipsing binaries and Cepheids (Kaluzny+ 1999)
J/AJ/118/2211 : M31F eclipsing binaries and Cepheids (Mochejska+ 1999)
http://cfa-www.harvard.edu/~kstanek/DIRECT : Direct Project
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- M31A Name (DIRECT VNNNN M31A in Simbad)
7- 13 F7.4 deg RAdeg Right ascension (J2000.0)
15- 21 F7.4 deg DEdeg Declination (J20000)
23- 26 F4.2 --- Js Variability index (Paper I, eq. (8))
28- 33 F6.3 d Per Period
35- 39 F5.2 mag Vmax V magnitude at maximum brightness
41- 45 F5.2 mag Imax ? Maximum I magnitude
47- 50 F4.2 --- Rad1 Radius of the primary component (1)
52- 55 F4.2 --- Rad2 Radius of the secondary component (1)
57- 58 I2 deg i Inclination angle
60- 63 F4.2 --- e Eccentricity
65- 74 A10 --- Com Comment (2)
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Note (1): The radii are in units of the orbital separation.
Note (2): V4636 D31A, with period P=8.181 days, is a good detached eclipsing
binary (DEB) candidate, with significant eccentricity.
V1555 D31A was found as V6913 D31B in Paper I, with identical period,
V_max_=20.63 and I_max_=20.06.
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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- 5 A5 --- M31A Name (DIRECT VNNNN M31A in Simbad)
7- 13 F7.4 deg RAdeg Right ascension (J2000.0)
15- 21 F7.4 deg DEdeg Declination (J2000.0)
23- 26 F4.2 --- Js Variability index
28- 33 F6.3 d Per Period
35- 39 F5.2 mag <V> Flux-weighted mean V magnitude
41- 45 F5.2 mag <I> ? Flux-weighted mean I magnitude
47- 50 F4.2 mag Amp Amplitude of the variation
52- 61 A10 --- Com Comments (1)
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Note (1): Ma97: Magnier et al., Cat. <J/A+AS/126/401>, [MAP97] in Simbad
Variable V2276 D31A (Ma97 108) was found as V7553 D31B in Paper I,
with period P=9.482 days, <V>=20.93, and <I>=19.77.
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Byte-by-byte Description of file: table3.dat, table4.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- M31A Name (DIRECT VNNNN M31A in Simbad)
7- 13 F7.4 deg RAdeg Right ascension (J2000.0)
15- 21 F7.4 deg DEdeg Declination (J2000.0)
23- 26 F4.2 --- Js Variability index
28- 32 F5.2 d Per ? Period (only in table3.dat)
34- 38 F5.2 mag Vbar Error-weighted mean V magnitude
40- 44 F5.2 mag Ibar ? Error-weighted mean I magnitude
46- 49 F4.2 mag e_Vmag Standard deviation in the V band
51- 54 F4.2 mag e_Imag ? Standard deviation in the I band
56- 65 A10 --- Com Comments (1)
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Note (1): Variables V3222, V541 and V11 of table4 where also found in Paper I.
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Byte-by-byte Description of file: table5.dat, table6.dat, table7.dat
Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- M31A Name (VNNNN)
7 A1 --- Band [IV] Band
9- 20 F12.4 d HJD Heliocentric Julian date
22- 27 F6.3 mag Mag Magnitude in the band (I or V)
29- 33 F5.3 mag e_Mag rms uncertainty on Mag
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History: From AJ electronic version
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(End) James Marcout, Patricia Bauer [CDS] 12-Aug-1998