J/A+A/333/205 HD 185510 UBV photometry (Frasca+ 1998)
Photospheric and chromospheric activity in the late-type giant component of the
evolved binary system HD 185510
Frasca A., Marilli E., Catalano S.
<Astron. Astrophys. 333, 205 (1998)>
=1998A&A...333..205F 1998A&A...333..205F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Stars, late-type ; Photometry, UBV
Keywords: stars: activity - binaries: eclipsing - subdwarfs -
stars: individual: HD 185510
Abstract:
UBV photometry and moderate resolution Hα spectrophotometry of
the evolved binary system HD 185510 (sdB + K0 III), performed at
Catania Astrophysical Observatory, is presented and discussed. The
spectrophotometric data were collected in 1991, 1993, and 1994, while
the photometric light curves were obtained in 1993, 1994 and 1995.
From the B and V photometry we determine a new photometric rotational
period of 26.23d, confirming the asynchronous rotation of the cool
giant component. The spectroscopic data confirm the vsin i value of
15km/s measured by Fekel et al. (1993AJ....106.2370F 1993AJ....106.2370F) and clearly
reveal a filled-in Hα line with appreciable variations. The
excess emission of the line, observed at any orbital phase, is found
to be anticorrelated with the V light curve and is primarily ascribed
to the chromospheric activity on the cool star. The primary total
eclipse is clearly visible in the U band, but undetectable in the V
band. From the U observations we determined a total duration of the
primary eclipse (from 1st to 4rd contact) of 1.3883d, with the
ingress lasting only 27 minutes. This new accurate monitoring and
timing of the eclipse allowed us to improve the system solution which
leads to RC=8.8R☉, TC=4800K, RH=0.11R☉, TH=30000K
for the cool and hot star respectively. The evolution of HD 185510B is
discussed also in relation to the evolutionary status of HD 185510A
and the synchronization time scale. HD 185510B is probably a sdB near
the zero age extended horizontal branch, resulting from an enhanced
mass loss in late case B or case A mass exchange with a possible
common envelope phase. A small amount (15-20%) of mass loss from the
system which can account for the strong IR excess is suggested.
Objects:
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RA (2000) DE Designation(s)
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19 39 38.6 -06 03 48 HD 185510
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 59 107 UBV photometry
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD Heliocentric Julian date
15- 20 F6.4 mag Vmag V magnitude
22- 27 F6.4 mag B-V B-V colour index
29- 34 F6.4 mag U-B U-B colour index
36- 41 F6.4 mag e_Vmag rms uncertainty on Vmag
43- 48 F6.4 mag e_B-V rms uncertainty on B-V
50- 55 F6.4 mag e_U-B rms uncertainty on U-B
57- 59 I3 --- Npt Number of points contributing to each listed
average value (1)
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Note (1): We have listed nightly means of UBV observations far from the ingress
or egresses eclipse phases.
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Acknowledgements: Antonio Frasca
(End) Patricia Bauer [CDS] 05-Feb-1998