TY - JOUR
T1 - A precise asteroseismic age and metallicity for HD 139614
T2 - A pre-main-sequence star with a protoplanetary disc in Upper Centaurus-Lupus
AU - Murphy, Simon J.
AU - Joyce, Meridith
AU - Bedding, Timothy R.
AU - White, Timothy R.
AU - Kama, Mihkel
N1 - Publisher Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2021/4/1
Y1 - 2021/4/1
N2 - HD 139614 is known to be a ∼14-Myr-old, possibly pre-main-sequence star in the Sco-Cen OB association in the Upper Centaurus-Lupus subgroup, with a slightly warped circumstellar disc containing ring structures hinting at one or more planets. The star's chemical abundance pattern is metal-deficient except for volatile elements, which places it in the λ Boo class and suggests it has recently accreted gas-rich but dust-poor material. We identify seven dipole and four radial pulsation modes among its δSct pulsations using the TESS light curve and an échelle diagram. Precision modelling with the mesa stellar evolution and gyre stellar oscillation programs confirms it is on the pre-main sequence. Asteroseismic, grid-based modelling suggests an age of 10.75 ± 0.77 Myr, a mass of 1.52 ± 0.02 M⊙, and a global metal abundance of Z = 0.0100 ± 0.0010. This represents the first asteroseismic determination of the bulk metallicity of a λ Boo star. The precise age and metallicity offer a benchmark for age estimates in Upper Centaurus-Lupus, and for understanding disc retention and planet formation around intermediate-mass stars.
AB - HD 139614 is known to be a ∼14-Myr-old, possibly pre-main-sequence star in the Sco-Cen OB association in the Upper Centaurus-Lupus subgroup, with a slightly warped circumstellar disc containing ring structures hinting at one or more planets. The star's chemical abundance pattern is metal-deficient except for volatile elements, which places it in the λ Boo class and suggests it has recently accreted gas-rich but dust-poor material. We identify seven dipole and four radial pulsation modes among its δSct pulsations using the TESS light curve and an échelle diagram. Precision modelling with the mesa stellar evolution and gyre stellar oscillation programs confirms it is on the pre-main sequence. Asteroseismic, grid-based modelling suggests an age of 10.75 ± 0.77 Myr, a mass of 1.52 ± 0.02 M⊙, and a global metal abundance of Z = 0.0100 ± 0.0010. This represents the first asteroseismic determination of the bulk metallicity of a λ Boo star. The precise age and metallicity offer a benchmark for age estimates in Upper Centaurus-Lupus, and for understanding disc retention and planet formation around intermediate-mass stars.
KW - asteroseismology
KW - protoplanetary discs
KW - stars: chemically peculiar
KW - stars: fundamental parameters
KW - stars: pre-main-sequence
KW - variables: Scuti
UR - http://www.scopus.com/inward/record.url?scp=85102375356&partnerID=8YFLogxK
U2 - 10.1093/mnras/stab144
DO - 10.1093/mnras/stab144
M3 - Article
SN - 0035-8711
VL - 502
SP - 1633
EP - 1646
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -