Exocomets size distribution in the $β$ Pictoris planetary system
A. Lecavelier des Etangs, L. Cros, G. Hébrard, E. Martioli, M. Duquesnoy, M. A. Kenworthy, F. Kiefer, S. Lacour, A. -M. Lagrange, N. Meunier, A. Vidal-Madjar
The star $β$ Pictoris harbors a young planetary system, which is characterized by the presence of a gaseous and dusty debris disk, at least two massive planets and many minor bodies. For more than thirty years, exocomets transiting the star have been detected using spectroscopy, probing the gaseous part of the cometary comas and tails.
The detection of the dusty component of the tails can be performed through photometric observations of the transits. Since 2018, the Transiting Exoplanet Survey Satellite has observed $β$ Pic for a total of 156 days. Here we report an analysis of the TESS photometric data set with the identification of a total of 30 transits of exocomets. Our statistical analysis shows that the number of transiting exocomet events ($N$) as a function of the absorption depth ($AD$) in the light curve follows a power law in the form $dN(AD) \propto AD^{-α}$, where $α=2.3\pm 0.4$. This distribution of absorption depth leads to a differential comet size distribution proportional to $R^{-γ}$, where $γ=3.6 \pm 0.8$, showing a striking similarity to the size distribution of comets in the Solar system and the distribution of a collisionally relaxed population ($γ_{\rm D}= 3.5$).
A Kinematic History of Stellar Encounters with Beta Pictoris
Centro de Astrobiología (CAB), CSIC-INTA（天体生物学中心）；Universidad Complutense de Madrid（马德里康普顿斯大学）；Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）；Lund University（隆德大学）；Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna (ULL)（拉各拉纳大学）
Lund University（隆德大学）；Observatoire astronomique de l’Université de Genève（日内瓦大学天文台）；University of Warwick（华威大学）；Centre for Exoplanets and Habitability, University of Warwick（华威系外行星与宜居性中心）；University of Exeter（埃克塞特大学）；University of Leeds（利兹大学）；Astronomical Institute of Slovak Academy of Sciences（斯洛伐克科学院天文研究所）；Main Astronomical Observatory of National Academy of Sciences of Ukraine（乌克兰国家科学院主天文台）；Gemini Observatory/NOIRLab（吉米天文台/美国国家光学红外天文研究实验室）
HD$\,$172555 is a young ($\sim$20$\,$Myr) A7V star surrounded by a 10$\,$au wide debris disk suspected to be replenished partly by collisions between large planetesimals. Small evaporating transiting bodies, exocomets, have also been detected in this system by spectroscopy. After $β\,$Pictoris, this is another example of a system possibly witnessing a phase of heavy bombardment of planetesimals. In such system, small bodies trace dynamical evolution processes. We aim at constraining their dust content by using transit photometry. We performed a 2-day-long photometric monitoring of HD$\,$172555…
A crucial diagnostic that can tell us about processes involved in the formation and dynamical evolutionof planetary systems is the angle between the rotation axis of a star and a planet's orbital angular momentum vector ("spin-orbit" alignment or "obliquity"). Here we present the first spin-orbit alignment measurement for a wide-separation exoplanetary system, namely on the directly-imaged planet $β$ Pictoris b. We use VLTI/GRAVITY spectro-interferometry with an astrometric accuracy of 1 $μ$as (microarcsecond) in the Br$γ$ photospheric absorption line to measure the photocenter displacement as…
Nearly 15 years of radial velocity (RV) monitoring and direct imaging enabled the detection of two giant planets orbiting the young, nearby star $β$ Pictoris. The $δ$ Scuti pulsations of the star, overwhelming planetary signals, need to be carefully suppressed. In this work, we independently revisit the analysis of the RV data following a different approach than in the literature to model the activity of the star. We show that a Gaussian Process (GP) with a stochastically driven damped harmonic oscillator kernel can model the $δ$ Scuti pulsations. It provides similar results as parametric mode…
Photometric monitoring of Beta Pictoris in 1981 showed anomalous fluctuations of up to 4% over several days, consistent with foreground material transiting the stellar disk. The subsequent discovery of the gas giant planet Beta Pictoris b and the predicted transit of its Hill sphere to within 0.1 au projected distance of the planet provided an opportunity to search for the transit of a circumplanetary disk in this $21\pm 4$ Myr-old planetary system. Continuous broadband photometric monitoring of Beta Pictoris requires ground-based observatories at multiple longitudes to provide redundancy and …
Photometric Variability and Rotation of Beta Pictoris b from JWST NIRCam Coronagraphic Imaging
University of Virginia（弗吉尼亚大学）；University of Edinburgh（爱丁堡大学）；Space Telescope Science Institute（太空望远镜科学研究所）；University of Toronto（多伦多大学）；American Museum of Natural History（美国自然历史博物馆）；Trinity College Dublin（都柏林三一学院）
Sparse aperture masking at the VLT II. Detection limits for the eight debris disks stars $β$ Pic, AU Mic, 49 Cet, $η$ Tel, Fomalhaut, g Lup, HD181327 and HR8799
