New light synthesis and spectrum synthesis constraints on a model for β Lyrae

A. P. Llnnell, Ivan - Hubeny, P. Harmanec

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

A suite of programs that calculates both synthetic light curves and synthetic spectra for a binary system with an optically thick accretion disk has been applied for the first time to β Lyrae A. Our results demonstrate that the standard accretion disk model by Hubeny & Plavec shows significant residuals from observations, both photometric and spectroscopic, and that no changes in adjustable parameters are able to remove the residuals. The basic problem is that the Hubeny & Plavec model requires a small visible segment of the hot star at the center of the accretion disk and this requirement conflicts with the photometric evidence. As an alternative, we investigate standard accretion disk models in which the central star is hidden from view. We find that no model of this type can satisfy either the observed photometry or the IUE spectra. To resolve this impasse, we suggest the presence of a light-scattering region above the accretion disk faces, which scatters light from the central star into the line of sight and provides the high-Teff radiation component required by both the light curves and the observed spectra. This source of radiation is very likely related to the jets proposed by Harmanec et al. and Hoffman et al. We calculate the location of stream impact on the accretion disk rim. Observations show no detectable photometric signature of a rim bright spot. We suggest that the liberated kinetic energy is spread over a region sufficiently large and at a sufficient optical depth to suppress appearance of a bright spot. A slight asymmetry of primary minimum may indicate swelling of the accretion disk rim down-stream from the stream impact point, with an attendant slight increase in obscuration of the background light sources.

Original languageEnglish (US)
Pages (from-to)379-391
Number of pages13
JournalAstrophysical Journal
Volume509
Issue number1 PART I
DOIs
StatePublished - 1998
Externally publishedYes

Fingerprint

accretion disks
accretion
synthesis
rims
light curve
point impact
stars
IUE
hot stars
occultation
light scattering
radiation
swelling
optical thickness
line of sight
optical depth
kinetic energy
photometry
asymmetry
light sources

Keywords

  • Accretion: accretion disks
  • Binaries: close
  • Binaries: eclipsing
  • Stars: individual (β Lyrae)

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

New light synthesis and spectrum synthesis constraints on a model for β Lyrae. / Llnnell, A. P.; Hubeny, Ivan -; Harmanec, P.

In: Astrophysical Journal, Vol. 509, No. 1 PART I, 1998, p. 379-391.

Research output: Contribution to journalArticle

Llnnell, A. P. ; Hubeny, Ivan - ; Harmanec, P. / New light synthesis and spectrum synthesis constraints on a model for β Lyrae. In: Astrophysical Journal. 1998 ; Vol. 509, No. 1 PART I. pp. 379-391.
@article{a51ea549735a494693970a875e00109f,
title = "New light synthesis and spectrum synthesis constraints on a model for β Lyrae",
abstract = "A suite of programs that calculates both synthetic light curves and synthetic spectra for a binary system with an optically thick accretion disk has been applied for the first time to β Lyrae A. Our results demonstrate that the standard accretion disk model by Hubeny & Plavec shows significant residuals from observations, both photometric and spectroscopic, and that no changes in adjustable parameters are able to remove the residuals. The basic problem is that the Hubeny & Plavec model requires a small visible segment of the hot star at the center of the accretion disk and this requirement conflicts with the photometric evidence. As an alternative, we investigate standard accretion disk models in which the central star is hidden from view. We find that no model of this type can satisfy either the observed photometry or the IUE spectra. To resolve this impasse, we suggest the presence of a light-scattering region above the accretion disk faces, which scatters light from the central star into the line of sight and provides the high-Teff radiation component required by both the light curves and the observed spectra. This source of radiation is very likely related to the jets proposed by Harmanec et al. and Hoffman et al. We calculate the location of stream impact on the accretion disk rim. Observations show no detectable photometric signature of a rim bright spot. We suggest that the liberated kinetic energy is spread over a region sufficiently large and at a sufficient optical depth to suppress appearance of a bright spot. A slight asymmetry of primary minimum may indicate swelling of the accretion disk rim down-stream from the stream impact point, with an attendant slight increase in obscuration of the background light sources.",
keywords = "Accretion: accretion disks, Binaries: close, Binaries: eclipsing, Stars: individual (β Lyrae)",
author = "Llnnell, {A. P.} and Hubeny, {Ivan -} and P. Harmanec",
year = "1998",
doi = "10.1086/306484",
language = "English (US)",
volume = "509",
pages = "379--391",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1 PART I",

}

TY - JOUR

T1 - New light synthesis and spectrum synthesis constraints on a model for β Lyrae

AU - Llnnell, A. P.

AU - Hubeny, Ivan -

AU - Harmanec, P.

PY - 1998

Y1 - 1998

N2 - A suite of programs that calculates both synthetic light curves and synthetic spectra for a binary system with an optically thick accretion disk has been applied for the first time to β Lyrae A. Our results demonstrate that the standard accretion disk model by Hubeny & Plavec shows significant residuals from observations, both photometric and spectroscopic, and that no changes in adjustable parameters are able to remove the residuals. The basic problem is that the Hubeny & Plavec model requires a small visible segment of the hot star at the center of the accretion disk and this requirement conflicts with the photometric evidence. As an alternative, we investigate standard accretion disk models in which the central star is hidden from view. We find that no model of this type can satisfy either the observed photometry or the IUE spectra. To resolve this impasse, we suggest the presence of a light-scattering region above the accretion disk faces, which scatters light from the central star into the line of sight and provides the high-Teff radiation component required by both the light curves and the observed spectra. This source of radiation is very likely related to the jets proposed by Harmanec et al. and Hoffman et al. We calculate the location of stream impact on the accretion disk rim. Observations show no detectable photometric signature of a rim bright spot. We suggest that the liberated kinetic energy is spread over a region sufficiently large and at a sufficient optical depth to suppress appearance of a bright spot. A slight asymmetry of primary minimum may indicate swelling of the accretion disk rim down-stream from the stream impact point, with an attendant slight increase in obscuration of the background light sources.

AB - A suite of programs that calculates both synthetic light curves and synthetic spectra for a binary system with an optically thick accretion disk has been applied for the first time to β Lyrae A. Our results demonstrate that the standard accretion disk model by Hubeny & Plavec shows significant residuals from observations, both photometric and spectroscopic, and that no changes in adjustable parameters are able to remove the residuals. The basic problem is that the Hubeny & Plavec model requires a small visible segment of the hot star at the center of the accretion disk and this requirement conflicts with the photometric evidence. As an alternative, we investigate standard accretion disk models in which the central star is hidden from view. We find that no model of this type can satisfy either the observed photometry or the IUE spectra. To resolve this impasse, we suggest the presence of a light-scattering region above the accretion disk faces, which scatters light from the central star into the line of sight and provides the high-Teff radiation component required by both the light curves and the observed spectra. This source of radiation is very likely related to the jets proposed by Harmanec et al. and Hoffman et al. We calculate the location of stream impact on the accretion disk rim. Observations show no detectable photometric signature of a rim bright spot. We suggest that the liberated kinetic energy is spread over a region sufficiently large and at a sufficient optical depth to suppress appearance of a bright spot. A slight asymmetry of primary minimum may indicate swelling of the accretion disk rim down-stream from the stream impact point, with an attendant slight increase in obscuration of the background light sources.

KW - Accretion: accretion disks

KW - Binaries: close

KW - Binaries: eclipsing

KW - Stars: individual (β Lyrae)

UR - http://www.scopus.com/inward/record.url?scp=22444456131&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=22444456131&partnerID=8YFLogxK

U2 - 10.1086/306484

DO - 10.1086/306484

M3 - Article

AN - SCOPUS:22444456131

VL - 509

SP - 379

EP - 391

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART I

ER -