The beta Pictoris system, with its two directly imaged planets beta Pic b and beta Pic c and its well characterised debris disk, is a prime target for detailed characterisation of young planetary systems. Here, we present high-resolution and high-contrast LM band spectroscopy with CRIRES+ of the system, primarily for the purpose of atmospheric characterisation of beta Pic b. We developed methods for determining slit geometry and wavelength calibration based on telluric absorption and emission lines, as well as methods for PSF modelling and subtraction, and artificial planet injection, in order to extract and characterise planet spectra at a high S/N and spectral fidelity. Through cross-correlation with model spectra, we detected H2O absorption for planet b in each of the 13 individual observations spanning four different spectral settings. This provides a clear confirmation of previously detected water absorption, and allowed us to derive an exquisite precision on the rotational velocity of beta Pic b, v_rot = 20.36 +/- 0.31 km/s, which is consistent within error bars with previous determinations. We also observed a tentative H2O cross-correlation peak at the expected position and velocity of planet c; the feature is however not at a statistically significant level. Despite a higher sensitivity to SiO than earlier studies, we do not confirm a tentative SiO feature previously reported for planet b. When combining data from different epochs and different observing modes for the strong H2O feature of planet b, we find that the S/N grows considerably faster when sets of different spectral settings are combined, compared to when multiple data sets of the same spectral setting are combined. This implies that maximising spectral coverage is often more important than maximising integration depth when investigating exoplanetary atmospheres using cross-correlation techniques.
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…
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 photom…
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 …
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）
The nearby young star beta Pictoris hosts a rich and complex planetary system, with at least two giant planets and a nearly edge-on debris disk that contains several dynamical subpopulations of planetesimals. While the inner ranges of the debris disk have been studied extensively, less information is known about the outer, fainter parts of the disk. Here we present an analysis of archival FORS V-band imaging data from 2003-2004, which have previously not been explored scientifically because the halo substructure of the bright stellar point spread function is complex. Through a high-contrast sc…
While beta Pic is known to host silicates in ring-like structures, whether the properties of these silicate dust vary with stellocentric distance remains an open question. We re-analyze the beta Pictoris debris disk spectrum from the Spitzer Infrared Spectrograph (IRS) and a new IRTF/SpeX spectrum to investigate trends in Fe/Mg ratio, shape, and crystallinity in grains as a function of wavelength, a proxy for stellocentric distance. By analyzing a re-calibrated and re-extracted spectrum, we identify a new 18 micron forsterite emission feature and recover a 23 micron forsterite emission feature…
The Birth of Minor-Body Populations in the $β$ Pictoris System I: The First 25 Myr
Universidad de La Laguna (ULL)（拉古纳大学）；Centro de Astrobiología (CAB), CSIC-INTA（天体生物学中心（CAB），CSIC-INTA）；Universidad Complutense de Madrid（马德里康普顿斯大学）；Lund University（隆德大学）
VLTI/MATISSE observations of the hot dust around $β$ Pictoris: Observing faint objects with MATISSE
Univ. Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学）；Univ. Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange（蔚蓝海岸大学，蔚蓝海岸天文台）；Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, HUN-REN（孔科利天文台，地球与天文学研究中心）；CSFK, MTA Centre of Excellence（匈牙利科学院天文学研究所，MTA卓越中心）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）
Discovery of an Exterior Third Planet Orbiting $β$ Pictoris
University of California, San Diego（加州大学圣地亚哥分校）；Space Telescope Science Institute（太空望远镜科学研究所）；The University of Arizona（亚利桑那大学）；California Institute of Technology（加州理工学院）；Center for Interdisciplinary Exploration and Research in Astrophysics（天体物理学跨学科探索与研究中心）；University of California, Santa Cruz（加州大学圣克鲁兹分校）；University of California Observatories（加州大学天文台）
We report on the high-resolution spectroscopic observations of two planetary transits of the hot Jupiter KELT-7b ($M_{\rm p}$ $=$ 1.28 $\pm$ 0.17 M$_{\rm Jup}$, $T_{\rm eq}$ $=$ 2028 K) observed with the High Optical Resolution Spectrograph (HORuS) mounted on the 10.4-m Gran Telescopio Canarias (GTC). A new set of stellar parameters are obtained for the rapidly rotating parent star from the analysis of the spectra. Using the newly derived stellar mass and radius, and the planetary transit data of the Transiting Exoplanet Survey Satellite (TESS) together with the HORuS velocities and the photom…
Chemical signatures of planetary systems in their host stars. Near-infrared spectroscopy of four planet-hosting wide binaries
Yonsei University（延世大学）；Chungnam National University（忠南国立大学）；Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut（海德堡大学天文计算研究所）；Korea Astronomy and Space Science Institute（韩国天体宇宙科学研究所）
The analysis of exoplanetary atmospheres by means of high-resolution spectroscopy is an expanding research field which provides information on chemical composition, thermal structure, atmospheric dynamics and orbital velocity of exoplanets. In this work, we aim at the detection of the light reflected by the exoplanet 51~Peg~b employing optical high-resolution spectroscopy. To detect the light reflected by the planetary dayside we use optical HARPS and HARPS-N spectra taken near the superior conjunction of the planet, when the flux contrast between the planet and the star is maximum. To search …
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）
Direct Imaging Discovery of Giant Exoplanet $β$ Pictoris d: A Decade-Long Game of Hide-and-Seek
Institute for Astronomy, University of Edinburgh（爱丁堡大学天文研究所）；Centre for Exoplanet Science, University of Edinburgh（爱丁堡大学系外行星科学中心）；European Southern Observatory（欧洲南方天文台）；Max Planck Institute for Intelligent Systems（马克斯·普朗克智能系统研究所）；Université Paris-Saclay（巴黎萨克雷大学）；Université Paris Cité（巴黎西岱大学）；CEA（法国原子能和替代能源委员会）；CNRS（法国国家科学研究中心）
通过VLT/ERIS、JWST/NIRCam和VLT/SPHERE的档案数据，直接成像发现了β Pictoris系统的第三颗系外行星d，其轨道半长轴26.0 au，质量2.4 M_Jup，温度600 K，与51 Eri b相似。
We present follow-up photometry and spectroscopy of ZTF J0328$-$1219 strengthening its status as a white dwarf exhibiting transiting planetary debris. Using TESS and Zwicky Transient Facility photometry, along with follow-up high speed photometry from various observatories, we find evidence for two significant periods of variability at 9.937 and 11.2 hr. We interpret these as most likely the orbital periods of different debris clumps. Changes in the detailed dip structures within the light curves are observed on nightly, weekly, and monthly timescales, reminiscent of the dynamic behavior obser…
A theory of transmission spectroscopy of hydrodynamic outflows from planetary atmospheres: Spectral-line saturation and limits on mass-loss constraints
Instituto de Astrofísica de Andalucía (IAA-CSIC)（安达卢西亚天体物理研究所）
Hydrocarbons are observed in the gas or solid phases of solar system objects, including comets, Trans-Neptunian Objects, planets and their moons. In the presence of water ice in these environments, hydrocarbons-bearing clathrate hydrates could form. In clathrate hydrates, guest molecules are trapped in crystalline water cages of different sizes, a phase used in models of planetary (sub-)surfaces or icy bodies such as comets. The phases in presence, the potential estimate of abundances of hydrocarbon species, the spectroscopic behaviour of hydrocarbon species in the different phases must be rec…
JWST promises to be the most versatile infrared observatory for the next two decades. The Near Infrared and Slitless Spectrograph (NIRISS) instrument, when used in the Aperture Masking Interferometry (AMI) mode, will provide an unparalleled combination of angular resolution and sensitivity compared to any existing observatory at mid-infrared wavelengths. Using simulated observations in conjunction with evolutionary models, we present the capability of this mode to image planetary mass companions around nearby stars at small orbital separations near the circumstellar water frost-line for member…
