J/A+AS/116/497 Radial velocities of 4 Cepheids (Imbert, 1996)
Cepheids and binarity. II. Radial velocities and spectroscopic orbits of four
galactic cepheids: RX Camelopardis, MW Cygni, Z Lacertae and U Vulpeculae
Imbert M.
<Astron. Astrophys. Suppl. Ser. 116, 497 (1996)>
=1996A&AS..116..497I 1996A&AS..116..497I (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Stars, variable
Keywords: stars: individual: RX Cam, MW Cyg, Z Lac, U vul - cepheids -
binaries: spectroscopic
Description:
Continued radial velocity observations over several years, have
allowed to discover four spectroscopic binary systems among our sample
of twenty five galactic Cepheids. Each system is composed by the
Cepheid and an invisible probably hot dwarf star. A spectroscopic
orbit has been determined for each system. The orbital periods for RX
Cam, MW Cyg, Z Lac and U Vul are 1113, 439, 383 and 2510 days,
respectively. For the pulsation motion, radial velocity versus phase
diagram have been fitted by an analytic relation, formally similar to
a Kepler motion. The stellar radius variation of each cepheid has been
derived by integration of this relation over the whole pulsating
period.
Objects:
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RA (2000) DE Name
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04 04 58.4 +58 39 35 RX Cam = HD 25361
20 12 22 +32 52.5 MW Cyg = HD 331970
22 40 52.1 +56 49 46 Z Lac = HD 214975
09 33 13.2 -45 30 55 U Vel = HD 82850
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2 75 401 Observed and calculated radial velocities
table5 63 194 Pulsation component of the radial velocity
(Coravel measures)
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Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Star name
8- 18 F11.4 --- OBSdate UT date of observation (ddmmyy.hhmm).
22- 33 F12.4 d HJD Heliocentric Julian date
36- 41 F6.2 km/s Vobs Observed velocity
44- 49 F6.2 km/s Vcal Calculated velocity (1)
52- 57 F6.2 km/s Vobs-Vcal Observed - calculated radial velocity
60 I1 --- Ref Source references (2)
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Note (1): Calculated velocity by superposition of the pulsation and orbital
motion following:
Vcal(t)=Vo+KP[eP(coswP)+cos(vP(t)+wP)]+Kb[eb(coswb)+cos(vb(t)+wb)]
+KG[eG(coswG)+cos(vG(t)+wG)]
Note (2): References are:
(1) Coravel
(2) Barnes et al. 1988 (1988ApJS...66...43B 1988ApJS...66...43B)
(3) Evans & Welch 1993 (1993PASP..105..836E 1993PASP..105..836E)
(4) Gieren 1989 (1989PASP..101..160G 1989PASP..101..160G)
(5) Gorynya et al. 1992a (1992PAZh...18..777G 1992PAZh...18..777G)
(6) Gorynya et al. 1992b (1992IBVS.3776....1G 1992IBVS.3776....1G)
(7) Joy 1937
(8) Sanford 1951 (1951ApJ...114..331S 1951ApJ...114..331S)
(9) Struve 1945
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Byte-by-byte Description of file: table5
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Star name
8- 18 F11.4 --- OBSdate Observation date (ddmmyy.hhmm)
22- 33 F12.4 d HJD Heliocentric Julian date
40- 45 F6.4 --- Phase [0/1[ Phase
48- 53 F6.2 km/s RVpul Pulsation component of the radial velocity
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References:
Barnes III T.G. et al., 1988, ApJS 66,43
Evans N.R. & Welch D.L., 1993, PASP 105, 836
Gieren W.P., 1989, PASP 101, 160
Gorynya N.A. et al., 1992a, Pis'ma Astron. Zh. 18, 777
Gorynya N.A. et al. 1992b, IBVS 3776
Joy A.H., 1937, ApJ 86, 263
Sanford R.F., 1951, ApJ 114, 331
Struve O., 1945, ApJ 102, 132
(End) Patricia Bauer [CDS] 15-Mar-1996