2006MNRAS.365..327H

Query : 2006MNRAS.365..327H

2006MNRAS.365..327H - Mon. Not. R. Astron. Soc., 365, 327-338 (2006/January-1)

Asteroseismology of the β Cephei star 12 (DD) Lacertae: photometric observations, pulsational frequency analysis and mode identification.

HANDLER G., JERZYKIEWICZ M., RODRIGUEZ E., UYTTERHOEVEN K., AMADO P.J., DOROKHOVA T.N., DOROKHOV N.I., PORETTI E., SAREYAN J.-P., PARRAO L., LORENZ D., ZSUFFA D., DRUMMOND R., DASZYNSKA-DASZKIEWICZ J., VERHOELST T., DE RIDDER J., ACKE B., BOURGE P.-O., MOVCHAN A.I., GARRIDO R., PAPARO M., SAHIN T., ANTOCI V., UDOVICHENKO S.N., CSORBA K., CROWE R., BERKEY B., STEWART S., TERRY D., MKRTICHIAN D.E. and AERTS C.

Abstract (from CDS):

We report a multisite photometric campaign for the β Cephei star 12 Lacertae. 750 h of high-quality differential photoelectric Strömgren, Johnson and Geneva time-series photometry were obtained with nine telescopes during 190 nights. Our frequency analysis results in the detection of 23 sinusoidal signals in the light curves. Ten of those correspond to independent pulsation modes, and the remainder are combination frequencies. We find some slow aperiodic variability such as that seemingly present in several β Cephei stars. We perform mode identification from our colour photometry, derive the spherical degree ℓ for the five strongest modes unambiguously and provide constraints on ℓ for the weaker modes. We find a mixture of modes of 0 ≤ℓ≤ 4. In particular, we prove that the previously suspected rotationally split triplet within the modes of 12 Lac consists of modes of different ℓ; their equal frequency splitting must thus be accidental.

One of the periodic signals we detected in the light curves is argued to be a linearly stable mode excited to visible amplitude by non-linear mode coupling via a 2:1 resonance. We also find a low-frequency signal in the light variations whose physical nature is unclear; it could be a parent or daughter mode resonantly coupled. The remaining combination frequencies are consistent with simple light-curve distortions.

The range of excited pulsation frequencies of 12 Lac may be sufficiently large that it cannot be reproduced by standard models. We suspect that the star has a larger metal abundance in the pulsational driving zone, a hypothesis also capable of explaining the presence of β Cephei stars in the Large Magellanic Cloud.


Abstract Copyright: 2005 The Authors. Journal compilation © 2005 RAS

Journal keyword(s): techniques: photometric - stars: early-type - stars: individual: 12 (DD) Lacertae - stars: oscillations - stars: variables: other

Errata: erratum vol. 426, p. 2600 (2012)

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 * nu. Eri bC* 04 36 19.1419185396 -03 21 08.857744927 2.82 3.737 3.928     B2III 407 0
2 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
3 * 1 Mon dS* 05 59 01.0801985544 -09 22 56.006401080   6.46 6.16     F2/3IV 157 0
4 V* KK Vel bC* 09 07 42.5207085395 -44 37 56.750000545 6.03 6.76 6.80     B2II/III 68 0
5 V* V836 Cen bC* 14 46 25.7601403800 -37 13 20.082887904 7.04 7.88 8.05     B2 124 0
6 * tet Oph bC* 17 22 00.5793468 -24 59 58.366974 2.18 3.03 3.26 3.38 3.58 OB 350 0
7 * 10 Lac ** 22 39 15.6786372 +39 03 00.971152 3.650 4.670 4.880 4.98 5.19 O9V 790 0
8 NAME I Lac As* 22 41 +38.5           ~ 158 0
9 * 12 Lac bC* 22 41 28.6495065456 +40 13 31.609736580 4.24 5.080 5.229     B1.5III 369 0
10 HD 216608 ** 22 53 40.1609179248 +44 44 57.015416328           kA3VmF2III/IVp 134 0
11 * 16 Lac bC* 22 56 23.6299283136 +41 36 13.948480440 4.61 5.436 5.587     B2IVs 325 0
12 * 2 And ** 23 02 36.38176 +42 45 28.0628           A1V 169 0
13 V* ZZ Psc WD* 23 28 47.6365087803 +05 14 54.235051503   13.217   13.106   DA4.1 536 0

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