Observational tests and predictive stellar evolution

P. A. Young, E. E. Mamajek, W David Arnett, James Liebert

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

We compare 18 binary systems with precisely determined radii and masses from 23 to 1.1 M and stellar evolution models produced with our newly revised code TYCHO. "Overshooting" and rotational mixing were suppressed in order to establish a baseline for isolating these and other hydrodynamic effects. Acceptable coeval fits are found for 16 pairs without optimizing for heavy-element or helium abundance. The precision of these tests is limited by the accuracies of the observed effective temperatures. High-dispersion spectra and detailed atmospheric modeling should give more accurate effective temperatures and heavy-element abundances. PV Cas, a peculiar early A system, EK Cep B, a known post-T Tauri star, and RS Cha, a member of a young OB association, are matched by pre-mainsequence models. Predicted mass loss agrees with upper limits from IUE for CW Cep A and B. Relatively poor fits are obtained for binaries having at least one component in the mass range 1.7 < M/M < 2.6, whose evolution is sensitive to mixing. These discrepancies are robust and consistent with additional mixing in real stars. The predicted apsidal motion implies that massive star models are systematically less centrally condensed than the real stars. If these effects are due to overshooting, then the overshooting parameter αov increases with stellar mass. The apsidal motion constants are controlled by radiative opacity under conditions close to those directly measured in laser experiments, making this test more stringent than possible before.

Original languageEnglish (US)
Pages (from-to)230-244
Number of pages15
JournalAstrophysical Journal
Volume556
Issue number1 PART 1
DOIs
StatePublished - Jul 20 2001

Fingerprint

stellar evolution
heavy elements
stars
IUE
T Tauri stars
opacity
stellar mass
massive stars
atmospheric modeling
helium
hydrodynamics
radii
temperature
laser
lasers
test
experiment
effect

Keywords

  • Atomic processes
  • Binaries: eclipsing
  • Color figures, machine-readable table
  • Hydrodynamics
  • Stars: evolution
  • Stars: fundamental parameters

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Young, P. A., Mamajek, E. E., Arnett, W. D., & Liebert, J. (2001). Observational tests and predictive stellar evolution. Astrophysical Journal, 556(1 PART 1), 230-244. https://doi.org/10.1086/321559

Observational tests and predictive stellar evolution. / Young, P. A.; Mamajek, E. E.; Arnett, W David; Liebert, James.

In: Astrophysical Journal, Vol. 556, No. 1 PART 1, 20.07.2001, p. 230-244.

Research output: Contribution to journalArticle

Young, PA, Mamajek, EE, Arnett, WD & Liebert, J 2001, 'Observational tests and predictive stellar evolution', Astrophysical Journal, vol. 556, no. 1 PART 1, pp. 230-244. https://doi.org/10.1086/321559
Young, P. A. ; Mamajek, E. E. ; Arnett, W David ; Liebert, James. / Observational tests and predictive stellar evolution. In: Astrophysical Journal. 2001 ; Vol. 556, No. 1 PART 1. pp. 230-244.
@article{cffa7db180be422ea8e5af33ba20508d,
title = "Observational tests and predictive stellar evolution",
abstract = "We compare 18 binary systems with precisely determined radii and masses from 23 to 1.1 M⊙ and stellar evolution models produced with our newly revised code TYCHO. {"}Overshooting{"} and rotational mixing were suppressed in order to establish a baseline for isolating these and other hydrodynamic effects. Acceptable coeval fits are found for 16 pairs without optimizing for heavy-element or helium abundance. The precision of these tests is limited by the accuracies of the observed effective temperatures. High-dispersion spectra and detailed atmospheric modeling should give more accurate effective temperatures and heavy-element abundances. PV Cas, a peculiar early A system, EK Cep B, a known post-T Tauri star, and RS Cha, a member of a young OB association, are matched by pre-mainsequence models. Predicted mass loss agrees with upper limits from IUE for CW Cep A and B. Relatively poor fits are obtained for binaries having at least one component in the mass range 1.7 < M/M⊙ < 2.6, whose evolution is sensitive to mixing. These discrepancies are robust and consistent with additional mixing in real stars. The predicted apsidal motion implies that massive star models are systematically less centrally condensed than the real stars. If these effects are due to overshooting, then the overshooting parameter αov increases with stellar mass. The apsidal motion constants are controlled by radiative opacity under conditions close to those directly measured in laser experiments, making this test more stringent than possible before.",
keywords = "Atomic processes, Binaries: eclipsing, Color figures, machine-readable table, Hydrodynamics, Stars: evolution, Stars: fundamental parameters",
author = "Young, {P. A.} and Mamajek, {E. E.} and Arnett, {W David} and James Liebert",
year = "2001",
month = "7",
day = "20",
doi = "10.1086/321559",
language = "English (US)",
volume = "556",
pages = "230--244",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1 PART 1",

}

TY - JOUR

T1 - Observational tests and predictive stellar evolution

AU - Young, P. A.

AU - Mamajek, E. E.

AU - Arnett, W David

AU - Liebert, James

PY - 2001/7/20

Y1 - 2001/7/20

N2 - We compare 18 binary systems with precisely determined radii and masses from 23 to 1.1 M⊙ and stellar evolution models produced with our newly revised code TYCHO. "Overshooting" and rotational mixing were suppressed in order to establish a baseline for isolating these and other hydrodynamic effects. Acceptable coeval fits are found for 16 pairs without optimizing for heavy-element or helium abundance. The precision of these tests is limited by the accuracies of the observed effective temperatures. High-dispersion spectra and detailed atmospheric modeling should give more accurate effective temperatures and heavy-element abundances. PV Cas, a peculiar early A system, EK Cep B, a known post-T Tauri star, and RS Cha, a member of a young OB association, are matched by pre-mainsequence models. Predicted mass loss agrees with upper limits from IUE for CW Cep A and B. Relatively poor fits are obtained for binaries having at least one component in the mass range 1.7 < M/M⊙ < 2.6, whose evolution is sensitive to mixing. These discrepancies are robust and consistent with additional mixing in real stars. The predicted apsidal motion implies that massive star models are systematically less centrally condensed than the real stars. If these effects are due to overshooting, then the overshooting parameter αov increases with stellar mass. The apsidal motion constants are controlled by radiative opacity under conditions close to those directly measured in laser experiments, making this test more stringent than possible before.

AB - We compare 18 binary systems with precisely determined radii and masses from 23 to 1.1 M⊙ and stellar evolution models produced with our newly revised code TYCHO. "Overshooting" and rotational mixing were suppressed in order to establish a baseline for isolating these and other hydrodynamic effects. Acceptable coeval fits are found for 16 pairs without optimizing for heavy-element or helium abundance. The precision of these tests is limited by the accuracies of the observed effective temperatures. High-dispersion spectra and detailed atmospheric modeling should give more accurate effective temperatures and heavy-element abundances. PV Cas, a peculiar early A system, EK Cep B, a known post-T Tauri star, and RS Cha, a member of a young OB association, are matched by pre-mainsequence models. Predicted mass loss agrees with upper limits from IUE for CW Cep A and B. Relatively poor fits are obtained for binaries having at least one component in the mass range 1.7 < M/M⊙ < 2.6, whose evolution is sensitive to mixing. These discrepancies are robust and consistent with additional mixing in real stars. The predicted apsidal motion implies that massive star models are systematically less centrally condensed than the real stars. If these effects are due to overshooting, then the overshooting parameter αov increases with stellar mass. The apsidal motion constants are controlled by radiative opacity under conditions close to those directly measured in laser experiments, making this test more stringent than possible before.

KW - Atomic processes

KW - Binaries: eclipsing

KW - Color figures, machine-readable table

KW - Hydrodynamics

KW - Stars: evolution

KW - Stars: fundamental parameters

UR - http://www.scopus.com/inward/record.url?scp=0035920047&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035920047&partnerID=8YFLogxK

U2 - 10.1086/321559

DO - 10.1086/321559

M3 - Article

AN - SCOPUS:0035920047

VL - 556

SP - 230

EP - 244

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART 1

ER -