Low-frequency variability and binarity of the<i>δ</i>Scuti star XX Pyx

Arentoft, T.; Sterken, C.; Handler, G.

doi:10.1046/j.1365-8711.2001.04594.x

Cited by 16 publications

(15 citation statements)

References 10 publications

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“…1 and de-noised following the method used for XX Pyx by Handler et al (2000), it is possibly caused by intrinsic low frequencies or binarity as shown by Arentoft et al (2001a). We have noted a similar sinusoidal amplitude variation appearing in the δ Sct star V1162 Ori (Arentoft et al 2001b), for which binarity (Arentoft & Sterken 2000) and multiperiodicity were proposed and well discussed.…”

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confidence: 56%

A comprehensive study of the δ Scuti star AN Lyncis

Zhou

2002

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Abstract. We present new time-series CCD photometry on the δ Scuti star AN Lyn. Analyses based on all the available data show that the amplitude of the main frequency increased from 1994 to 2000 at a rate of 0.006 mmag yr −1 . Considering all the existing amplitudes, the amplitude variations seem sinusoidal since 1980. In both periods of 1980-1983 and 1994-2001 with data available the amplitudes increased linearly with time. The amplitudes in the earlier 1980s were higher and they increased at a higher rate than those in 1994-2001. Amplitude variations of the other frequencies are also present from season to season. The light variation of AN Lyn can be explained currently by amplitude variability plus multiperiodic pulsation. However, no conclusion can be drawn regarding change of periods and new oscillation contents. The two independent frequencies f1 = 10.1756 cycle d

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confidence: 56%

A comprehensive study of the δ Scuti star AN Lyncis

Zhou

2002

A&A

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“…Handler et al (2000) found 22 independent Scuti frequencies in this A4 dwarf from an 81 day multisite photometric campaign; Arentoft, Sterken, & Handler (2001) found the low-frequency light variation, which they Fig. 6.-Computed radial-velocity curve of HD 207651 Aa compared with the six unit-weight observations.…”

Section: Discussionmentioning

confidence: 90%

HD 207651: A Triple System with Scuti and Ellipsoidal Variations But No Doradus Pulsations

2004

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We examine HD 207651 as a possible example of a star exhibiting both Doradus and Scuti type pulsations. We find photometric periods of 0.06479 and 0.06337 days with peak-to-peak amplitudes in Johnson B of 21 and 13 mmag, respectively, clearly indicating Scuti pulsations. Additional light variation with a period of 0.73540 days and an even larger amplitude of 31 mmag is within the range of Doradus pulsation periods but results instead from the ellipticity effect. HD 207651 has a composite spectrum with a weak, narrow absorption line superposed near the center of each broad metal line. The broad-lined component is the primary of a shortperiod, single-lined binary, which has a period of 1.4708 days, twice the period of the ellipsoidal variations seen in the photometry. We determine the primary to be an A8 giant and estimate the unseen secondary of the shortperiod binary to be a mid-M dwarf. The narrow-lined star, an F7: dwarf, shows velocity variability with a period of months or perhaps years. It is thus a more distant companion to the binary, making HD 207651 a triple system. All light variations come from the A8 giant primary star. Since the 0.73540 day variation results from the ellipticity effect, HD 207651 is not an example of a star that exhibits both Scuti and Doradus pulsations. The growing number of confirmed Doradus stars that also occur within the Scuti instability strip but fail to show additional Scuti variability makes it increasingly unlikely that the two types of pulsation can coexist in the same star.

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“…Arentoft, Sterken & Handler (2001) shed new light on the nature of XX Pyx by suggesting the presence of a close companion. This hypothesis was based on two facts:…”

Section: Introductionmentioning

confidence: 99%

“…Arentoft et al (2001) concluded that XX Pyx may have a low‐mass companion and gave some preliminary constraints on its mass and the orbital inclination based on the velocity shift in the spectra published by Handler et al (1997).…”

Section: Introductionmentioning

confidence: 99%

Theδ Scuti star XX Pyx is an ellipsoidal variable

Aerts¹,

Handler²,

Arentoft³

et al. 2002

Monthly Notices of the Royal Astronomical Society

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We present spectroscopic and multicolour photometric evidence supporting the binary nature of the δ Scuti star XX Pyx (CD–24 7599). Applying a cross‐correlation technique to the spectra, we find clear radial‐velocity variations with a large amplitude. We derive the orbital parameters and confirm an orbital period of 1.15 d, as suggested previously on the basis of photometric variations. The amplitude of the slow variations present in our new multicolour data is wavelength independent, pointing also to a geometric effect as origin of the variability. They are thus fully consistent with the spectral variations and are interpreted as ellipsoidal variations. XX Pyx has a circular orbit of which the radial‐velocity variations have a semi‐amplitude of 17.8±0.4 km s‐1. The single‐lined binary nature of the star, together with the mass function, lead us to conclude that the orbital inclination must be larger than 10°. The orbital solution is compatible with a synchronized M3V companion. The deformation of the primary due to tidal forces is very probably the reason for the failure of detailed seismic modelling efforts done recently.

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Low-frequency variability and binarity of theδScuti star XX Pyx

Cited by 16 publications

References 10 publications

A comprehensive study of the δ Scuti star AN Lyncis

A comprehensive study of the δ Scuti star AN Lyncis

HD 207651: A Triple System with Scuti and Ellipsoidal Variations But No Doradus Pulsations

Theδ Scuti star XX Pyx is an ellipsoidal variable

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