A Tight Upper Limit on Oscillations in the Ap Star Ursae Majoris from
                    <i>WIRE</i>
                    Photometry

Retter, A.; Bedding, Timothy R.; Buzasi, Derek L.; Kjeldsen, H.; Kiss, L. L.

doi:10.1086/381889

Cited by 7 publications

(10 citation statements)

References 31 publications

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“…We also attempted to use spectroscopic observations obtained by the International Ultraviolet Explorer (IUE) and Copernicus space missions available via the Multimission Archive at STScl 1 . Finally, we used a dataset of photometric observations carried out by the Wide Field Infrared Explorer (WIRE) obtained during June-July 2000, although we had to rejected several parts strongly affected by instrumental effects and instabilities (see Retter et al 2004, for details).…”

Section: Observationsmentioning

confidence: 99%

“…Measurements taken in various narrow-and broad-band filters were divided into 10 groups according to their effective wavelengths -see Table 3. We also used a very extensive data-set of WIRE photometry (Retter et al 2004), which was unfortunately unreliable in several ways:…”

Section: Improved Ephemerismentioning

confidence: 99%

“…(1), ϕ Guth can be transformed to new phases according to Eq. (7), ϕ new by means of the relation ϕ new = ϕ Guth + 2.648 × 10 −6 (t − 2 431 960) (Molnar 1975), -10-color medium-band photometry (Musielok et al 1980); ubvy photometry of Pyper & Adelman (1985); ∇ − BV (Provin 1953); − Hipparcos photometry (ESA 1997), and small full circles relate to broad-band photometry of WIRE (Retter et al 2004) -each point is the median of 1600 individual time-consecutive measurements.…”

Section: Improved Ephemerismentioning

confidence: 99%

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Modelling the light variability of the Ap starε Ursae Majoris

Shulyak

Krtička

Mikulášek

et al. 2010

A&A

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Aims. We simulate the light variability of the Ap star ε UMa using the observed surface distributions of Fe, Cr, Ca, Mn, Mg, Sr, and Ti obtained with the help of the Doppler imaging technique. Methods. Using all photometric data available, we specified light variations of ε UMa modulated by its rotation from far UV to IR. We employed the LLmodels stellar model atmosphere code to predict the light variability in different photometric systems. Results. The rotational period of ε UMa is refined to 5.d 088631(18). It is shown that the observed light variability can be explained as a result of the redistribution of radiative flux from the UV spectral region to the visual caused by the inhomogeneous surface distribution of chemical elements. Among seven mapped elements, only Fe and Cr contribute significantly to the amplitude of the observed light variability. In general, we find very good agreement between theory and observations. We confirm the important role of Fe and Cr in determining the magnitude of the well-known depression around 5200 Å by analyzing the peculiar a-parameter. Finally, we show that the abundance spots of considered elements cannot explain the observed variabilities in near UV and β index, which probably have other causes. Conclusions. The inhomogeneous surface distribution of chemical elements can explain most of the observed light variability of the A-type CP star ε UMa.

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Section: Observationsmentioning

confidence: 99%

Section: Improved Ephemerismentioning

confidence: 99%

Section: Improved Ephemerismentioning

confidence: 99%

See 1 more Smart Citation

Modelling the light variability of the Ap starε Ursae Majoris

Shulyak

Krtička

Mikulášek

et al. 2010

A&A

View full text Add to dashboard Cite

show abstract

“…Oscillations excited by turbulent convection – solar‐like oscillations – have been successfully identified in cool main‐sequence and post‐main‐sequence stars with convective envelopes. In the red giants, solar‐like oscillations have been first detected by ground‐based observations (Merline 1999; Frandsen et al 2002; Stello et al 2004) and by the Wide Field Infrared Explorer ( WIRE ) satellite (Buzasi et al 2000; Retter et al 2003, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…sequence and post-main-sequence stars with convective envelopes. In the red giants, solar-like oscillations have been first detected by ground-based observations (Merline 1999;Frandsen et al 2002;Stello et al 2004) and by the WIRE satellite Retter et al 2003Retter et al , 2004.…”

mentioning

confidence: 98%

Solar-like oscillations from the depths of the red-giant star KIC 4351319 observed with Kepler

Mauro

Cardini

Catanzaro

et al. 2011

Monthly Notices of the Royal Astronomical Society

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We present the results of the asteroseismic analysis of the red‐giant star KIC 4351319 (TYC 3124‐914‐1), observed for 30 d in short‐cadence mode with the Kepler satellite. The analysis has allowed us to determine the large and small frequency separations, Hz and Hz, respectively, and the frequency of maximum oscillation power, Hz. The high signal‐to‐noise ratio of the observations allowed us to identify 25 independent pulsation modes whose frequencies range approximately from 300 to Hz. The observed oscillation frequencies together with the accurate determination of the atmospheric parameters (effective temperature, gravity and metallicity), provided by additional ground‐based spectroscopic observations, enabled us to theoretically interpret the observed oscillation spectrum. KIC 4351319 appears to oscillate with a well‐defined solar‐type p‐mode pattern due to radial acoustic modes and non‐radial nearly pure p modes. In addition, several non‐radial mixed modes have been identified. Theoretical models well reproduce the observed oscillation frequencies and indicate that this star, located at the base of the ascending red‐giant branch, is in the hydrogen‐shell‐burning phase, with a mass of ∼1.3 M⊙, a radius of and an age of ∼5.6 Gyr. The main parameters of this star have been determined with an unprecedented level of precision for a red‐giant star, with uncertainties of 2 per cent for mass, 7 per cent for age, 1 per cent for radius and 4 per cent for luminosity.

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No stellar p-mode oscillations in space-based photometry of Procyon

Matthews

Kuschnig

Guenther

et al. 2004

Nature

137

130

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Pressure-driven (p-mode) oscillations at the surface of the Sun, resulting from sound waves travelling through the solar interior, are a powerful probe of solar structure, just as seismology can reveal details about the interior of the Earth. Astronomers have hoped to exploit p-mode asteroseismology in Sun-like stars to test detailed models of stellar structure and evolution, but the observations are extremely difficult. The bright star Procyon has been considered one of the best candidates for asteroseismology, on the basis of models and previous reports of p-modes detected in ground-based spectroscopy. Here we present a search for p-modes in 32 days of nearly continuous photometric satellite-based observations of Procyon. If there are p-modes in Procyon, they must have lifetimes less than 2-3 days and/or peak amplitudes <15 parts per million, which defy expectations from the Sun's oscillations and previous theoretical predictions. Target selection for future planned asteroseismology space missions may need to be reconsidered, as will the theory of stellar oscillations.

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A Tight Upper Limit on Oscillations in the Ap Star Ursae Majoris from WIRE Photometry

Cited by 7 publications

References 31 publications

Modelling the light variability of the Ap starε Ursae Majoris

Modelling the light variability of the Ap starε Ursae Majoris

Solar-like oscillations from the depths of the red-giant star KIC 4351319 observed with Kepler

No stellar p-mode oscillations in space-based photometry of Procyon

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