Seismological modeling of the Delta Scuti star: CD-24 7599

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A major goal of asteroseismology is a better understanding of stellar evolution via ``snapshots`` of many stars of different masses in different evolutionary states. For stars of about 2M{sub {circle_dot}} near the sequence, b Scuti stars are the usual suspects. There is an ongoing renaissance in theoretical modeling of 6 Scuti stars brought on by improvements in constitutive physics and by a dramatic increase in the number of modes observed. FG Virginis and CD-24` 7599 are two of the best studied objects, and they have 19 and 13 known frequencies, respectively. . We create models using an updated and modified ... continued below

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Bradley, P.A. & Guzik, J.A. November 1, 1996.

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A major goal of asteroseismology is a better understanding of stellar evolution via ``snapshots`` of many stars of different masses in different evolutionary states. For stars of about 2M{sub {circle_dot}} near the sequence, b Scuti stars are the usual suspects. There is an ongoing renaissance in theoretical modeling of 6 Scuti stars brought on by improvements in constitutive physics and by a dramatic increase in the number of modes observed. FG Virginis and CD-24` 7599 are two of the best studied objects, and they have 19 and 13 known frequencies, respectively. . We create models using an updated and modified version of the Iben code described by Guzik & Cox that includes either of the two versions of the OPAL opacities . We use the star`s observed location on the H-R diagram as a starting point for our seismological modeling. Because there is no evidence for observed t = 3 modes, we only consider l = 0, 1, and 2 modes in our analysis. We take into account rotational splitting (about 5 - 10 {mu}Hz) in our frequency matching. Several observed modes must be rotationally split members of a given mode. CD-24` 7599 is less than halfway through core hydrogen burning, and the modes appear to be a set of consecutive 3rd through 5th overtones of {ital l} = 0 through 2 modes. With only 13 modes, we find satisfactory fits with models between 1.9 and 2.0 M{sub {circle_dot}} that fall within the observed luminosity and effective temperature range. By contrast, Guzik & Bradley suggest that FG Virginis is over halfway through core hydrogen burning and the best fitting models lie near 1.80 or 2.00 M{sub {circle_dot}}. We see persistent discrepancies in some low frequency modes, which suggests we may need a small amount of core overshoot or a slight change in metallicity to duplicate FG Virginis.

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3 p.

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OSTI as DE97000375

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  • International Astronomical Union (IAU) symposium 181: sounding solar and stellar interiors, Nice (France), 30 Sep - 3 Oct 1996

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  • Other: DE97000375
  • Report No.: LA-UR--96-3420
  • Report No.: CONF-9609278--1
  • Grant Number: W-7405-ENG-36
  • Office of Scientific & Technical Information Report Number: 399358
  • Archival Resource Key: ark:/67531/metadc686965

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  • November 1, 1996

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  • July 25, 2015, 2:20 a.m.

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  • Aug. 8, 2016, 8:36 p.m.

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Bradley, P.A. & Guzik, J.A. Seismological modeling of the Delta Scuti star: CD-24 7599, article, November 1, 1996; New Mexico. (digital.library.unt.edu/ark:/67531/metadc686965/: accessed November 18, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.