J/A+A/454/855 Geneva photometry of W Cru (Pavlovski+, 2006)
Indirect imaging of an aacretion disk rim in the long-period interacting
binary W Crucis.
Pavlovski, K., Burki, G., Mimica P.
<Astron. Astrophys. 454, 855 (2006)>
=2006A&A...454..855P 2006A&A...454..855P
ADC_Keywords: Binaries, eclipsing ; Photometry, Geneva
Keywords: binaries: eclipsing - accretion disk: image - techniques: photometry
Abstract:
Light curves of the long-period Algols are known for their complex
(asymmetry in the eclipse, light variations outside the eclipse,
changes from cycle-to-cycle), but their interpretation is not possible
in the standard model of binary stars. We determined that complex
structures present in these active Algol systems could be studied with
the eclipse-mapping method that was successfully applied to the new
7-color photometric observations in the Geneva system of W Cru,
belonging to the isolated group of these active Algols. Several cycles
of this long-period (198.5-days) eclipsing binary were covered by
observations. We used a modified Rutten's approach to the
eclipse-mapping. The optimization of the system's parameters and the
recovery of the disk intensity distribution are performed using a
genetic algorithm (GA). The finding of a primary (hot) component is
hidden in thick accretion disk confirms previous solutions. The mass
of the primary component, M1=8.2M☉, indicates that it is a
mid-B type star. The mass-losing component fills its critical lobe,
which, for the system's parameters, means it is a G-type supergiant
with a mass M2=1.6M☉. The disk is very extended geometrically,
and its outer radius is about 80% of the primary's critical lobe. A
reconstructed image reveals the rather clumpy and nonuniform
brightness distribution of an accretion disk rim in this system that
is seen almost edge-on. This clumpiness accounts for light curve
distortions and asymmetries, as well as for secular changes.
Description:
The 386 photometric measurements of W Cru (HD 105998) in the 7-colour
Geneva system.
Objects:
-------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------
12 11 59.2 -58 47 01 W Cru = HD 105998
-------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 67 386 Photometric measurements of W Cru in the
7-colour Geneva system
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.3 d HJD Heliocentric Julian date
13 I1 --- Q [0/4] Photometric Q weight
(Rufener 1988, Cat. II/169) (1)
17- 21 F5.3 mag Vmag Magnitude in the visible
23 I1 --- P [0/4] Photometric P weight
(Rufener 1988, Cat. II/169) (1)
27- 31 F5.3 mag [U-B] Geneva [U-B] colour index
33- 38 F6.3 mag [V-B] Geneva [V-B] colour index
40- 44 F5.3 mag [B1-B] Geneva [B1-B] colour index
46- 50 F5.3 mag [B2-B] Geneva [B2-B] colour index
52- 56 F5.3 mag [V1-B] Geneva [V1-B] colour index
58- 62 F5.3 mag [G-B] Geneva [G-B] colour index
64- 67 F4.2 --- Fz Airmass
--------------------------------------------------------------------------------
Note (1): Photometric weight as follows:
4 = observation of exceptional quality whose correlation with
standards is remarkably well assured.
3 = normal weight for all the good measurements conveniently
correlated with standards.
2 = weight conferred as soon as the least doubt exists as to the
transparency or correlation with standards.
1 = weight conferred as soon as no certainty of good transparency
and good correlation with standards can be obtained (case of
partial night for instance).
0 = this weight sanctions all measurement for which an objective
risk of error exists.
--------------------------------------------------------------------------------
Acknowledgements: Gilbert Burki, Gilbert.Burki(at)obs.unige.ch
(End) Kresimir Pavlovski [UniZagreb, Croatia], P. Vannier [CDS] 13-Jul-2006