Observations of Cepheids with the MOST satellite

Contrast between pulsation modes

N. R. Evans, R. Szabó, A. Derekas, L. Szabados, C. Cameron, J. M. Matthews, D. Sasselov, R. Kuschnig, J. F. Rowe, D. B. Guenther, A. F J Moffat, S. M. Rucinski, W. W. Weiss

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode and one pulsating in the first overtone with the Canadian MOST (Microvariability and Oscillations of Stars) satellite. The 3.7-d period fundamental mode pulsator (RT Aur) has a light curve that repeats precisely, and can be modelled by a Fourier series very accurately. The overtone pulsator (SZ Tau, 3.1 d period) on the other hand shows light-curve variation from cycle to cycle which we characterize by the variations in the Fourier parameters. We present arguments that we are seeing instability in the pulsation cycle of the overtone pulsator, and that this is also a characteristic of the O - C curves of overtone pulsators. On the other hand, deviations from cycle to cycle as a function of pulsation phase follow a similar pattern in both stars, increasing after minimum radius. In summary, pulsation in the overtone pulsator is less stable than that of the fundamental mode pulsator at both long and short time-scales.

Original languageEnglish
Pages (from-to)4008-4018
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume446
Issue number4
DOIs
Publication statusPublished - 2014

Fingerprint

oscillation
harmonics
stars
oscillations
cycles
satellite data
light curve
timescale
Fourier series
strings
deviation
radii
curves
parameter

Keywords

  • Stars: individual: RT Aur
  • Stars: individual: SZ Tau
  • Stars: variables: Cepheids
  • Techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Observations of Cepheids with the MOST satellite : Contrast between pulsation modes. / Evans, N. R.; Szabó, R.; Derekas, A.; Szabados, L.; Cameron, C.; Matthews, J. M.; Sasselov, D.; Kuschnig, R.; Rowe, J. F.; Guenther, D. B.; Moffat, A. F J; Rucinski, S. M.; Weiss, W. W.

In: Monthly Notices of the Royal Astronomical Society, Vol. 446, No. 4, 2014, p. 4008-4018.

Research output: Contribution to journalArticle

Evans, NR, Szabó, R, Derekas, A, Szabados, L, Cameron, C, Matthews, JM, Sasselov, D, Kuschnig, R, Rowe, JF, Guenther, DB, Moffat, AFJ, Rucinski, SM & Weiss, WW 2014, 'Observations of Cepheids with the MOST satellite: Contrast between pulsation modes', Monthly Notices of the Royal Astronomical Society, vol. 446, no. 4, pp. 4008-4018. https://doi.org/10.1093/mnras/stu2371
Evans, N. R. ; Szabó, R. ; Derekas, A. ; Szabados, L. ; Cameron, C. ; Matthews, J. M. ; Sasselov, D. ; Kuschnig, R. ; Rowe, J. F. ; Guenther, D. B. ; Moffat, A. F J ; Rucinski, S. M. ; Weiss, W. W. / Observations of Cepheids with the MOST satellite : Contrast between pulsation modes. In: Monthly Notices of the Royal Astronomical Society. 2014 ; Vol. 446, No. 4. pp. 4008-4018.
@article{f40e28ba5bc443cfae2d85492d29d037,
title = "Observations of Cepheids with the MOST satellite: Contrast between pulsation modes",
abstract = "The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode and one pulsating in the first overtone with the Canadian MOST (Microvariability and Oscillations of Stars) satellite. The 3.7-d period fundamental mode pulsator (RT Aur) has a light curve that repeats precisely, and can be modelled by a Fourier series very accurately. The overtone pulsator (SZ Tau, 3.1 d period) on the other hand shows light-curve variation from cycle to cycle which we characterize by the variations in the Fourier parameters. We present arguments that we are seeing instability in the pulsation cycle of the overtone pulsator, and that this is also a characteristic of the O - C curves of overtone pulsators. On the other hand, deviations from cycle to cycle as a function of pulsation phase follow a similar pattern in both stars, increasing after minimum radius. In summary, pulsation in the overtone pulsator is less stable than that of the fundamental mode pulsator at both long and short time-scales.",
keywords = "Stars: individual: RT Aur, Stars: individual: SZ Tau, Stars: variables: Cepheids, Techniques: photometric",
author = "Evans, {N. R.} and R. Szab{\'o} and A. Derekas and L. Szabados and C. Cameron and Matthews, {J. M.} and D. Sasselov and R. Kuschnig and Rowe, {J. F.} and Guenther, {D. B.} and Moffat, {A. F J} and Rucinski, {S. M.} and Weiss, {W. W.}",
year = "2014",
doi = "10.1093/mnras/stu2371",
language = "English",
volume = "446",
pages = "4008--4018",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "4",

}

TY - JOUR

T1 - Observations of Cepheids with the MOST satellite

T2 - Contrast between pulsation modes

AU - Evans, N. R.

AU - Szabó, R.

AU - Derekas, A.

AU - Szabados, L.

AU - Cameron, C.

AU - Matthews, J. M.

AU - Sasselov, D.

AU - Kuschnig, R.

AU - Rowe, J. F.

AU - Guenther, D. B.

AU - Moffat, A. F J

AU - Rucinski, S. M.

AU - Weiss, W. W.

PY - 2014

Y1 - 2014

N2 - The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode and one pulsating in the first overtone with the Canadian MOST (Microvariability and Oscillations of Stars) satellite. The 3.7-d period fundamental mode pulsator (RT Aur) has a light curve that repeats precisely, and can be modelled by a Fourier series very accurately. The overtone pulsator (SZ Tau, 3.1 d period) on the other hand shows light-curve variation from cycle to cycle which we characterize by the variations in the Fourier parameters. We present arguments that we are seeing instability in the pulsation cycle of the overtone pulsator, and that this is also a characteristic of the O - C curves of overtone pulsators. On the other hand, deviations from cycle to cycle as a function of pulsation phase follow a similar pattern in both stars, increasing after minimum radius. In summary, pulsation in the overtone pulsator is less stable than that of the fundamental mode pulsator at both long and short time-scales.

AB - The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode and one pulsating in the first overtone with the Canadian MOST (Microvariability and Oscillations of Stars) satellite. The 3.7-d period fundamental mode pulsator (RT Aur) has a light curve that repeats precisely, and can be modelled by a Fourier series very accurately. The overtone pulsator (SZ Tau, 3.1 d period) on the other hand shows light-curve variation from cycle to cycle which we characterize by the variations in the Fourier parameters. We present arguments that we are seeing instability in the pulsation cycle of the overtone pulsator, and that this is also a characteristic of the O - C curves of overtone pulsators. On the other hand, deviations from cycle to cycle as a function of pulsation phase follow a similar pattern in both stars, increasing after minimum radius. In summary, pulsation in the overtone pulsator is less stable than that of the fundamental mode pulsator at both long and short time-scales.

KW - Stars: individual: RT Aur

KW - Stars: individual: SZ Tau

KW - Stars: variables: Cepheids

KW - Techniques: photometric

UR - http://www.scopus.com/inward/record.url?scp=84985911296&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84985911296&partnerID=8YFLogxK

U2 - 10.1093/mnras/stu2371

DO - 10.1093/mnras/stu2371

M3 - Article

VL - 446

SP - 4008

EP - 4018

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -