TY - JOUR
T1 - Pulsation of the Lambda Bootis star HD 210111
AU - Breger, M.
AU - Beck, P.
AU - Lenz, P.
AU - Schmitzberger, L.
AU - Guggenberger, E.
AU - Shobbrook, R. R.
PY - 2006/8
Y1 - 2006/8
N2 - Context. The λ Bootis stars are a small spectroscopic subgroup of Population I A-type stars and show significant underabundances of metals. Many are δ Scuti pulsators. Aims. HD 210111 was selected for a detailed multisite pulsation study to determine whether its pulsation properties differ from those of normal A stars. Methods. 262 h of high-precision photometry were obtained at the SAAO and SSO observatories. Results. 13 statistically significant pulsation frequencies were detected with very small photometric amplitudes from 1 to 7 millimag in the visual. A comparison with earlier 1994 measurements indicates a small increase in amplitude. As a byproduct, one of the comparison stars, HD 210571, was discovered to be a millimag variable with a frequency of 1.235 cd-1 and is probably a new γ Doradus variable. The observed wide range of excited frequencies from 12 to 30 cd -1 in HD 210111 can be explained with both the single- and double-star hypothesis. HD 210111 is in a similar evolutionary status to FG Vir, which also shows a wide range of excited frequencies with a similar frequency spacing near 4 cd-1. This is interpreted as successive radial orders of the excited nonradial modes. In the double-star hypothesis previously evoked for HD 210111, the low and the high frequencies originate in different stars: here HD 210111 would resemble Θ2 Tau. Conclusions. The pulsation of the λ Bootis star HD 210111 does not differ from that of normal δ Scuti stars.
AB - Context. The λ Bootis stars are a small spectroscopic subgroup of Population I A-type stars and show significant underabundances of metals. Many are δ Scuti pulsators. Aims. HD 210111 was selected for a detailed multisite pulsation study to determine whether its pulsation properties differ from those of normal A stars. Methods. 262 h of high-precision photometry were obtained at the SAAO and SSO observatories. Results. 13 statistically significant pulsation frequencies were detected with very small photometric amplitudes from 1 to 7 millimag in the visual. A comparison with earlier 1994 measurements indicates a small increase in amplitude. As a byproduct, one of the comparison stars, HD 210571, was discovered to be a millimag variable with a frequency of 1.235 cd-1 and is probably a new γ Doradus variable. The observed wide range of excited frequencies from 12 to 30 cd -1 in HD 210111 can be explained with both the single- and double-star hypothesis. HD 210111 is in a similar evolutionary status to FG Vir, which also shows a wide range of excited frequencies with a similar frequency spacing near 4 cd-1. This is interpreted as successive radial orders of the excited nonradial modes. In the double-star hypothesis previously evoked for HD 210111, the low and the high frequencies originate in different stars: here HD 210111 would resemble Θ2 Tau. Conclusions. The pulsation of the λ Bootis star HD 210111 does not differ from that of normal δ Scuti stars.
KW - Stars: chemically peculiar
KW - Stars: individual: HD 210111
KW - Stars: individual: HD 210571
KW - Stars: oscillations
KW - Stars: variables: δ Sct
UR - http://www.scopus.com/inward/record.url?scp=33748419513&partnerID=8YFLogxK
U2 - 10.1051/0004-6361:20065457
DO - 10.1051/0004-6361:20065457
M3 - Article
SN - 0004-6361
VL - 455
SP - 673
EP - 677
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
IS - 2
ER -