J/ApJ/679/1490 Photometry and Velocity of 3 ζ Aur binaries (Eaton+, 2007)
Orbits and pulsations of the classical ζ Aurigae binaries.
Eaton J.A., Henry G.W., Odell A.P.
<Astrophys. J., 679, 1490-1498 (2008)>
=2008ApJ...679.1490E 2008ApJ...679.1490E
ADC_Keywords: Binaries, spectroscopic ; Radial velocities ; Equivalent widths ;
Photometry, UBV
Keywords: binaries: spectroscopic - stars: late-type - stars: oscillations
Abstract:
We have derived new orbits for ζ Aur, 32 Cyg, and 31 Cyg with
observations from the Tennessee State University (TSU) Automatic
Spectroscopic Telescope, and used them to identify nonorbital
velocities of the cool supergiant components of these systems. Our
concurrent photometry detected the nonradial pulsations driven by
tides (ellipsoidal variation) in both ζ Aur and 32 Cyg, at a
level and phasing roughly consistent with simple theory to first
order, although they seem to require moderately large gravity
darkening. We point out two fundamental questions in the
interpretation of these stars: (1) whether it is appropriate to model
the surface brightness as gravity darkening and (2) whether much of
the nonorbital velocity structure may actually represent changes in
the convective flows in the stars' atmospheres.
Description:
All data come from the completely automatic observatory Tennessee
State University (TSU) maintains at Fairborn Observatory, a private
site in southern Arizona. We observed ζ Aur, 31 Cyg, and 32 Cyg
between JD 2452860 and 2454200, obtaining echelle spectra of roughly
30000 resolution. This set consists of 302, 217, and 348 useful
spectra, respectively, for the three stars. We also collected BV
observations of the three stars with the TSU 0.4m Automatic
Photometric Telescope (APT), obtaining measurements over complete
cycles of both ζ Aur and 32 Cyg and 4.0yr for 31 Cyg.
Objects:
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RA (2000) DE Designation(s) (Period)
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05 02 28.7 +41 04 33 zeta Aur = HD 32068 = HR 1612 (P=972.162)
20 15 28.3 +47 42 51 32 Cyg = HD 192909 = HR 7751 (P=3786.1)
20 13 37.9 +46 44 29 31 Cyg = HD 192577 = HR 7735 (P=1147.80)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 41 867 Spectroscopic Data
table3.dat 64 1905 Photometric Data
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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- 12 F12.4 d HJD Heliocentric Julian Date
14- 19 F6.2 km/s RV Radial velocity of the K star (1)
21- 25 F5.3 0.1nm EW1 Equivalent width of Hα absorption
27- 31 F5.3 0.1nm EW2 Equivalent width of enhanced absorption in
the blue wing of Hα
33- 34 A2 --- --- [HD]
36- 41 I6 --- HD HD identification
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Note (1): The measured velocities from the AST (Automatic Spectroscopic
Telescope) have a formal external error of 0.10-0.11km/s and are
0.35±0.09km/s more negative than the IAU radial-velocity system.
The velocities in Table 2 are the raw velocities without the +0.35km/s
correction to the IAU system.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian Date
14- 19 F6.3 mag DUvar ?=99.999 Differential U band magnitude
21- 26 F6.3 mag DBvar ?=99.999 Differential B band magnitude
28- 33 F6.3 mag DVvar ?=99.999 Differential V band magnitude
35- 40 F6.3 mag DUchk ?=99.999 Check star differential U band magnitude
42- 47 F6.3 mag DBchk ?=99.999 Check star differential B band magnitude
49- 54 F6.3 mag DVchk ?=99.999 Check star differential V band magnitude
56- 57 A2 --- --- [HD]
59- 64 I6 --- HD HD identification
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 11-Oct-2010