TheδScuti pulsations ofβPictoris as observed by ASTEP from Antarctica

Abstract

Aims. The Antarctica Search for Transiting Extrasolar Planets (ASTEP), an automatized 400 mm telescope located at Concordia station in Antarctica, monitored β Pictoris continuously to detect any variability linked to the transit of the Hill sphere of its planet β Pictoris b. The long observation sequence, from March to September 2017, combined with the quality and high level duty cycle of our data, enables us to detect and analyse the δ Scuti pulsations of the star. Methods. Time series photometric data were obtained using aperture photometry by telescope defocussing. The 66 418 data points were analysed using the software package Period04. We only selected frequencies with amplitudes that exceed four times the local noise level in the amplitude spectrum. Results. We detect 31 δ Scuti pulsation frequencies, 28 of which are new detections. All the frequencies detected are in the interval 34.76−75.68 d −1 . We also find that β Pictoris exhibits at least one pulsation mode that varies in amplitude over our monitoring duration of seven months.

Exocomets: A spectroscopic survey

“…27 that stars with both stable and/or sporadic CS features tend to be in many cases located above the main sequence, in the δ Scuti instability strip of the HR diagram (Breger 1979;Rodriguez et al 1994). A few of the hotgas-bearing stars in our sample are identified as δ Scuti stars in SIMBAD -HD 110411, HD 183324, and HD 192518; recently, Mellon et al (2019) have found that HD 156623 is also a δ Scuti star; we also point out that β Pic itself has δ Scuti pulsations (Koen 2003;Mékarnia et al 2017). In addition, the CS gas stars have distinctly larger v sin i.…”

Transiting exocomets detected in broadband light by TESS in the β Pictoris system

“…Future work includes a more comprehensive modelling of all the transits seen in the TESS light curve, and a study of whether high resolution spectral observations were taken simultaneously with this transit to confirm the cometary hypothesis. A comprehensive photometric campaign was conducted during the Hill sphere transit of β Pictoris b (Kenworthy 2017), which includes bRing (Stuik et al 2017), ASTEP (Guillot et al 2015;Abe et al 2013;Mékarnia et al 2017), and BRITE-Constellation (Weiss et al 2014) photometry. Searching this data may yield more candidate broadband transits.…”

Very regular high-frequency pulsation modes in young intermediate-mass stars

“…• β Pictoris: known to be a high-frequency δ Scuti star 88,89 , but a value for the large separation has not been reported. The TESS observations indicate a value of ∆ν = 6.95 d −1 (Fig.…”