New submissions for Monday, 17 June 2024

Auto update Star Formation & Molecular Cloud papers at about 2:30am UTC (10:30am Beijing time) every weekday.

阅读 Usage.md了解如何使用此repo实现个性化的Arxiv论文推送

See Usage.md for instructions on how to personalize the repo.

Keyword list: ['star formation', 'star-forming', 'molecular cloud', 'interstellar medium', 'cloud', 'clump', 'core', 'filament', 'atomic gas', 'N-PDF']

Excluded: ['galaxies', 'galaxy cluster', ' AGN ']

Today: 14papers

Time dependence of neutrino quantum kinetics in a core-collapse supernova

Authors: Shashank Shalgar, Irene Tamborra
Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics - Phenomenology (hep-ph)
Arxiv link: https://arxiv.org/abs/2406.09504
Pdf link: https://arxiv.org/pdf/2406.09504
Abstract Our understanding of neutrino flavor conversion in the supernova core is still preliminary, despite its likely relevance to the neutrino-driven supernova mechanism. We present multi-angle and multi-energy numerical simulations of neutrino quantum kinetics within a spherically symmetric shell in the proximity of the region of neutrino decoupling. We rely on inputs from a one-dimensional core-collapse supernova model with a mass of $18.6\ M_\odot$ and find that, at early post-bounce times ($t_{\mathrm pb} \lesssim 0.5$ s), no crossing is present in the angular distribution of the electron neutrino lepton number and flavor conversion develops due to vacuum mixing. Angular crossings appear for $t_{\textrm{pb}} \gtrsim 0.5$ s and fast flavor conversion leads to flavor equipartition, with the spectral energy distribution of $\nu_{e}$ ($\bar{\nu}{e}$) and $\nu{x}$ ($\bar{\nu}{x}$) becoming comparable. Notably, flavor equipartition is not a generic outcome of fast flavor conversion, but rather a consequence of the relatively similar properties of neutrinos of different flavors characterizing the late accretion phase. Artificially tweaking the collision term to introduce an electron lepton number angular crossing for $t{\mathrm{pb}} \lesssim 0.05$ s, we observe that flavor equipartition is not achieved. While our findings are restricted to a specific supernova model, they suggest a rich phenomenology of flavor conversion in the supernova core as a function of the post-bounce time which needs to be further explored to assess its impact on the explosion mechanism.

JWST/NIRCam 4-5 $\mu$m Imaging of the Giant Planet AF Lep b

Authors: Kyle Franson, William O. Balmer, Brendan P. Bowler, Laurent Pueyo, Yifan Zhou, Emily Rickman, Zhoujian Zhang, Sagnick Mukherjee, Tim D. Pearce, Daniella C. Bardalez Gagliuffi, Lauren I. Biddle, Timothy D. Brandt, Rachel Bowens-Rubin, Justin R. Grepp, James W. Davidson Jr., Jacqueline Faherty, Christian Kinski, Elliott P. Horch, Marvin Morgan, Caroline V. Morley, Marshall D. Perrin, Aniket Sanghi, Maissa Salama, Christopher A. Theissen, Quang H. Tran, Trevor N. Wolf
Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Arxiv link: https://arxiv.org/abs/2406.09528
Pdf link: https://arxiv.org/pdf/2406.09528
Abstract With a dynamical mass of $3 , M_\mathrm{Jup}$, the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectral type near the L/T transition make it a promising target to study the impact of clouds and atmospheric chemistry at low surface gravities. In this work, we present JWST/NIRCam imaging of AF Lep b. Across two epochs, we detect AF Lep b in F444W ($4.4 , \mathrm{\mu m}$) with S/N ratios of 9.6 and 8.7, respectively. At the planet's separation of $320 , \mathrm{mas}$ during the observations, the coronagraphic throughput is ${\approx}7%$, demonstrating that NIRCam's excellent sensitivity persists down to small separations. The F444W photometry of AF Lep b affirms the presence of disequilibrium carbon chemistry and enhanced atmospheric metallicity. These observations also place deep limits on wider-separation planets in the system, ruling out $1.1 , M_\mathrm{Jup}$ planets beyond $15.6 , \mathrm{au}$ (0.58 arcsec), $1.1 , M_\mathrm{Sat}$ planets beyond $27 , \mathrm{au}$ (1 arcsec), and $2.8 , M_\mathrm{Nep}$ planets beyond $67 , \mathrm{au}$ (2.5 arcsec). We also present new Keck/NIRC2 $L'$ imaging of AF Lep b; combining this with the two epochs of F444W photometry and previous Keck $L'$ photometry provides limits on the long-term 3-$5 , \mathrm{\mu m}$ variability of AF Lep b on months-to-years timescales. AF Lep b is the closest-separation planet imaged with JWST to date, demonstrating that planets can be recovered well inside the nominal (50% throughput) NIRCam coronagraph inner working angle.

Turbulence and the characteristics of circumstellar discs

Authors: R. Riaz, D. R. G. Schleicher, S. Vanaverbeke, R. Klessen, J. Saavedra-Bastidas
Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
Arxiv link: https://arxiv.org/abs/2406.09594
Pdf link: https://arxiv.org/pdf/2406.09594
Abstract We investigate the properties of circumstellar discs (CDs) produced in hydrodynamical simulations of gravoturbulent core collapse considering Kolmogorov and Burger-type turbulence. We report that massive discs are more prevalent in the Kolmogorov regime than for Burger-type turbulence. A significant number of discs are formed with a radius of $\sim$ 15 au in both cases. However, the number of extended discs with radii $>$ 15 au is significantly larger in case of Kolmogorov turbulence. The two regimes of turbulence, in general, yield disc radii in the ranges of 7 au $-$ 30 au, and 13 au $-$ 39 au, respectively. The corresponding ranges of the disc masses are 30.37 $M_{\rm Jup}$ $-$ 0.92 M${\odot}$, and 2.09 $M{\rm Jup}$ $-$ 0.13 M${\odot}$, respectively. Moreover, the ratio $M{\rm disc}$/$M_{\rm star}$ is higher in models of Kolmogorov-type turbulence than in models of Burgers-type turbulence. We do not find any correlation between $R_{\rm disc}$ and $M_{\rm disc}$ over the explored range of initial temperatures (8 K $-$ 14 K) and the type of turbulence. Also, for these initial thermal variations, the turbulent circumstellar disc structures do not exhibit signs of turbulent diffusion. Nonetheless, both sub and supersonic velocity dispersions cause variations in the specific angular momentum (AM) of infalling gas, especially for CDs with radii $\sim$ 16 au $-$ 21 au. The radial profiles of CDs do not correlate with the initial conditions.

Dust-Evacuated Zones Near Massive Stars: Consequences of Dust Dynamics on Star-forming Regions

Authors: Nadine H. Soliman, Philip F. Hopkins, Michael Y. Grudić
Subjects: Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Arxiv link: https://arxiv.org/abs/2406.09602
Pdf link: https://arxiv.org/pdf/2406.09602
Abstract Stars form within dense cores composed of both gas and dust within molecular clouds. However, despite the crucial role that dust plays in the star formation process, its dynamics is frequently overlooked, with the common assumption being a constant, spatially uniform dust-to-gas ratio and grain size spectrum. In this study, we introduce a set of radiation-dust-magnetohydrodynamic simulations of star forming molecular clouds from the {\small STARFORGE} project. These simulations expand upon the earlier radiation MHD models, which included cooling, individual star formation, and feedback. Notably, they explicitly address the dynamics of dust grains, considering radiation, drag, and Lorentz forces acting on a diverse size spectrum of live dust grains. We find that interactions between radiation and dust significantly influence the properties of gas surrounding and accreting onto massive stars. Specifically, we find that once stars exceed a certain mass threshold ($\sim 2 M_{\odot}$), their emitted radiation can evacuate dust grains from their vicinity, giving rise to a dust-suppressed zone of size $\sim 100$ AU. Commencing during the early accretion stages and preceding the Main-sequence phase, this process results in a mass-dependent depletion in the accreted dust-to-gas (ADG) mass ratio within both the circumstellar disc and the star. We predict massive stars ($\gtrsim 10 M_{\odot}$) would exhibit ADG ratios that are approximately one order of magnitude lower than that of their parent clouds. Consequently, stars, their discs, and circumstellar environments would display notable deviations in the abundances of elements commonly associated with dust grains, such as carbon and oxygen.

Phase-resolving the absorption signatures of water and carbon monoxide in the atmosphere of the ultra-hot Jupiter WASP-121b with GEMINI-S/IGRINS

Authors: Joost P. Wardenier, Vivien Parmentier, Michael R. Line, Megan Weiner Mansfield, Xianyu Tan, Shang-Min Tsai, Jacob L. Bean, Jayne L. Birkby, Matteo Brogi, Jean-Michel Désert, Siddharth Gandhi, Elspeth K. H. Lee, Colette I. Levens, Lorenzo Pino, Peter C. B. Smith
Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Arxiv link: https://arxiv.org/abs/2406.09641
Pdf link: https://arxiv.org/pdf/2406.09641
Abstract Ultra-hot Jupiters are among the best targets for atmospheric characterization at high spectral resolution. Resolving their transmission spectra as a function of orbital phase offers a unique window into the 3D nature of these objects. In this work, we present three transits of the ultra-hot Jupiter WASP-121b observed with Gemini-S/IGRINS. For the first time, we measure the phase-dependent absorption signals of CO and H${\text{2}}$O in the atmosphere of an exoplanet, and we find that they are different. While the blueshift of CO increases during the transit, the absorption lines of H${\text{2}}$O become less blueshifted with phase, and even show a redshift in the second half of the transit. These measurements reveal the distinct spatial distributions of both molecules across the atmospheres of ultra-hot Jupiters. Also, we find that the H${\text{2}}$O signal is absent in the first quarter of the transit, potentially hinting at cloud formation on the evening terminator of WASP-121b. To further interpret the absorption trails of CO and H${\text{2}}$O, as well as the Doppler shifts of Fe previously measured with VLT/ESPRESSO, we compare the data to simulated transits of WASP-121b. To this end, we post-processes the outputs of global circulation models with a 3D Monte-Carlo radiative transfer code. Our analysis shows that the atmosphere of WASP-121b is subject to atmospheric drag, as previously suggested by small hotspot offsets inferred from phase-curve observations. Our study highlights the importance of phase-resolved spectroscopy in unravelling the complex atmospheric structure of ultra-hot Jupiters and sets the stage for further investigations into their chemistry and dynamics.

Simulating Brown Dwarf Observations for Various Mass Functions, Birthrates, and Low-mass Cutoffs

Authors: Yadukrishna Raghu, J. Davy Kirkpatrick, Federico Marocco, Christopher R. Gelino, Daniella C. Bardalez Gagliuffi, Jacqueline K. Faherty, Steven D. Schurr, Adam C. Schneider, Aaron M. Meisner, Marc J. Kuchner, Hunter Brooks, Jake Grigorian, The Backyard Worlds: Planet 9 Collaboration
Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Arxiv link: https://arxiv.org/abs/2406.09690
Pdf link: https://arxiv.org/pdf/2406.09690
Abstract After decades of brown dwarf discovery and follow-up, we can now infer the functional form of the mass distribution within 20 parsecs, which serves as a constraint on star formation theory at the lowest masses. Unlike objects on the main sequence that have a clear luminosity-to-mass correlation, brown dwarfs lack a correlation between an observable parameter (luminosity, spectral type, or color) and mass. A measurement of the brown dwarf mass function must therefore be procured through proxy measurements and theoretical models. We utilize various assumed forms of the mass function, together with a variety of birthrate functions, low-mass cutoffs, and theoretical evolutionary models, to build predicted forms of the effective temperature distribution. We then determine the best fit of the observed effective temperature distribution to these predictions, which in turn reveals the most likely mass function. We find that a simple power law ($dN/dM \propto M^{-\alpha}$) with $\alpha \approx 0.5$ is optimal. Additionally, we conclude that the low-mass cutoff for star formation is $\lesssim0.005M_{\odot}$. We corroborate the findings of Burgasser (2004) which state that the birthrate has a far lesser impact than the mass function on the form of the temperature distribution, but we note that our alternate birthrates tend to favor slightly smaller values of $\alpha$ than the constant birthrate. Our code for simulating these distributions is publicly available. As another use case for this code, we present findings on the width and location of the subdwarf temperature gap by simulating distributions of very old (8-10 Gyr) brown dwarfs.

The gravitational-wave emission from the explosion of a 15 solar mass star with rotation and magnetic fields

Authors: Jade Powell, Bernhard Müller
Subjects: Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)
Arxiv link: https://arxiv.org/abs/2406.09691
Pdf link: https://arxiv.org/pdf/2406.09691
Abstract Gravitational waveform predictions from 3D simulations of explosions of non-rotating massive stars with no magnetic fields have been extensively studied. However, the impact of magnetic fields and rotation on the core-collapse supernova gravitational-wave signal is not well understood beyond the core-bounce phase. Therefore, we perform four magnetohydrodynamical simulations of the explosion of a $15,M_{\odot}$ star with the SFHx and SFHo equations of state. All of the models start with a weak magnetic field strength of $10^{8}$,G, and two of the models are rapidly rotating. We discuss the impact of the rotation and magnetic fields on the gravitational-wave signals. We find that the weak pre-collapse fields do not have a significant impact on the gravitational-wave signal amplitude. With rapid rotation, the f/g-mode trajectory can change in shape, and the dominant emission band becomes broader. We include the low-frequency memory component of the gravitational-wave signal from both matter motions and neutrino emission anisotropy. We show that including the gravitational waves from anisotropic neutrino emission increases the supernova detection distances for the Einstein Telescope, and would also be detectable out to Mpc distances by a moon-based gravitational-wave detector.

Evidence for Morning-to-Evening Limb Asymmetry on the Cool Low-Density Exoplanet WASP-107b

Authors: Matthew M. Murphy, Thomas G. Beatty, Everett Schlawin, Taylor J. Bell, Michael R. Line, Thomas P. Greene, Vivien Parmentier, Emily Rauscher, Luis Welbanks, Jonathan J. Fortney, Marcia Rieke
Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Arxiv link: https://arxiv.org/abs/2406.09863
Pdf link: https://arxiv.org/pdf/2406.09863
Abstract Transmission spectroscopy has enabled unprecedented insights into the makeup of exoplanet atmospheres. A transmission spectrum combines contributions from a planet's morning and evening limbs, but these limbs may have different temperatures, compositions, and aerosol properties due to atmospheric circulation. High-resolution ground-based observations have detected limb asymmetry on several ultra-hot (>2000 K) exoplanets, but space-based investigation into limb asymmetry is in its infancy, and limb asymmetry's prevalence in the broader exoplanet population remains unexplored. We find evidence for limb asymmetry on the exoplanet WASP-107b via transmission spectroscopy from 2.5 to 4.0 micrometers with JWST/NIRCam. This is one of the first low-resolution space-based measurements of limb asymmetry and is unique because, at 770 K, WASP-107b is in a relatively cool regime where planetary terminators are expected to be homogeneous. These observations imply a difference in temperature and cloud properties between WASP-107b's limbs, challenging our models of limb asymmetry in this cooler regime.

The nucleosynthetic fingerprint of the outermost protoplanetary disk and early Solar System dynamics

Authors: Elishevah van Kooten, Xuchao Zhao, Ian Franchi, Po-Yen Tung, Simon Fairclough, John Walmsley, Isaac Onyett, Martin Schiller, Martin Bizzarro
Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Arxiv link: https://arxiv.org/abs/2406.09893
Pdf link: https://arxiv.org/pdf/2406.09893
Abstract Knowledge of the nucleosynthetic isotope composition of the outermost protoplanetary disk is critical to understand the formation and early dynamical evolution of the Solar System. We report the discovery of outer disk material preserved in a pristine meteorite based on its chemical composition, organic-rich petrology, and 15N-rich, deuterium-rich, and 16O-poor isotope signatures. We infer that this outer disk material originated in the comet-forming region. The nucleosynthetic Fe, Mg, Si and Cr compositions of this material reveal that, contrary to current belief, the isotope signature of the comet-forming region is ubiquitous amongst outer Solar System bodies, possibly reflecting an important planetary building block in the outer Solar System. This nucleosynthetic component represents fresh material added to the outer disk by late accretion streamers connected to the ambient molecular cloud. Our results show that most Solar System carbonaceous asteroids accreted material from the comet-forming region, a signature lacking in the terrestrial planet region.

Interstellar Neutral Hydrogen in the Heliosphere: New Horizons Observations in the Context of Models

Authors: P. Swaczyna, M. Bzowski, K. Dialynas, L. Dyke, F. Fraternale, A. Galli, J. Heerikhuisen, M. Z. Kornbleuth, D. Koutroumpa, I. Kowalska-Leszczyńska, M. A. Kubiak, A. T. Michael, H.-R. Müller, M. Opher, F. Rahmanifard
Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics of Galaxies (astro-ph.GA); Space Physics (physics.space-ph)
Arxiv link: https://arxiv.org/abs/2406.09915
Pdf link: https://arxiv.org/pdf/2406.09915
Abstract Interstellar neutral (ISN) hydrogen is the most abundant species in the outer heliosheath and the very local interstellar medium (VLISM). Charge exchange collisions in the outer heliosheath result in filtration, reducing the ISN hydrogen density inside the heliosphere. Additionally, these atoms are intensively ionized close to the Sun, resulting in a substantial reduction of their density within a few au from the Sun. The products of this ionization - pickup ions (PUIs) - are detected by charged particle detectors. The Solar Wind Around Pluto (SWAP) instrument on New Horizons provides, for the first time, PUI observations from the distant heliosphere. We analyze the observations collected between 22 and 52 au from the Sun to find the ISN hydrogen density profile and compare the results with predictions from global heliosphere models. We conclude that the density profile derived from the observations is inconsistent with steady-state model predictions. This discrepancy is not explained by time variations close to the Sun and thus may be related to the temporal evolution of the outer boundaries or VLISM conditions. Furthermore, we show that the cold and hot models of ISN hydrogen distribution are not a good approximation closer to the termination shock. Therefore, we recommend a new fiduciary point based on the available New Horizons observations at 40 au from the Sun, at ecliptic direction (285.62°, 1.94°), where the ISN hydrogen density is 0.11 cm$^{-3}$. The continued operation of New Horizons should give better insight into the source of the discussed discrepancy.

GASTLI: An open-source coupled interior-atmosphere model to unveil gas giant composition

Authors: Lorena Acuña, Laura Kreidberg, Meng Zhai, Paul Mollière
Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Arxiv link: https://arxiv.org/abs/2406.10032
Pdf link: https://arxiv.org/pdf/2406.10032
Abstract The metal mass fractions of gas giants are a powerful tool to constrain their formation mechanisms and evolution. The metal content is inferred by comparing mass and radius measurements with interior structure and evolution models. In the midst of the JWST, CHEOPS, TESS, and the forthcoming PLATO era, we are at the brink of obtaining unprecedented precision in radius, age and atmospheric metallicity measurements. To prepare for this wealth of data, we present the GAS gianT modeL for Interiors (GASTLI), an easy-to-use, publicly available Python package. The code is optimized to rapidly calculate mass-radius relations, and radius and luminosity thermal evolution curves for a variety of envelope compositions and core mass fractions. Its applicability spans planets with masses $17 \ M_{\oplus} < M < 6 \ M_{Jup}$, and equilibrium temperatures $T_{eq} < 1000$ K. The interior model is stratified in a core composed of water and rock, and an envelope constituted by H/He and metals (water). The interior is coupled to a grid of self-consistent, cloud-free atmospheric models to determine the atmospheric and boundary interior temperature, as well as the contribution of the atmosphere to the total radius. We successfully validate GASTLI by comparing it to previous work and data of the Solar System's gas giants and Neptune. We also test GASTLI on the Neptune-mass exoplanet HAT-P-26 b, finding a bulk metal mass fraction between 0.60-0.78 and a core mass of 8.5-14.4 $M_{\oplus}$. Finally, we explore the impact of different equations of state and assumptions, such as C/O ratio and transit pressure, in the estimation of bulk metal mass fraction. These differences between interior models entail a change in radius of up to 2.5% for Jupiter-mass planets, but more than 10% for Neptune-mass. These are equivalent to variations in core mass fraction of 0.07, or 0.10 in envelope metal mass fraction.

Carbon Monoxide Cooling in Radiative Transfer Modeling of Supernovae

Authors: Collin McLeod, D. John Hillier, Luc Dessart
Subjects: Subjects: Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE)
Arxiv link: https://arxiv.org/abs/2406.10132
Pdf link: https://arxiv.org/pdf/2406.10132
Abstract Carbon monoxide (CO) emission has been observed in a number of core-collapse supernovae (SNe) and is known to be an important coolant at late times. We have implemented a chemical reaction network in the radiative-transfer code CMFGEN to investigate the formation of CO and its impact on SN ejecta. We calculate two 1D SN models with and without CO: a BSG explosion model at one nebular epoch and a full time sequence (50 to 300 days) for a RSG explosion. In both models, CO forms at nebular times in the dense, inner regions at velocities $<2000 \mathrm{km/s}$ where line emission from CO can dominate the cooling and reduce the local temperature by as much as a factor of two, weakening emission lines and causing the optical light curve to fade faster. That energy is instead emitted in CO bands, primarily the fundamental band at $\sim 4.5\mathrm{\mu m}$, which accounts for up to 20% of the total luminosity at late times. However, the non-monotonic nature of the CO cooling function can cause numerical difficulties and introduce multiple temperature solutions. This issue is compounded by the sensitivity of the CO abundance to a few reaction rates, many of which have large uncertainties or disparate values across literature sources. Our results also suggest that, in many SNe, CO level populations are far from their LTE values. Unfortunately, accurate collisional data, necessary to compute NLTE populations, are limited to a few transitions.

DESI and the Hubble tension in light of modified recombination

Authors: Gabriel P. Lynch, Lloyd Knox, Jens Chluba
Subjects: Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Arxiv link: https://arxiv.org/abs/2406.10202
Pdf link: https://arxiv.org/pdf/2406.10202
Abstract Recent measurements and analyses from the Dark Energy Spectroscopic Instrument (DESI) Collaboration and supernova surveys combined with cosmic microwave background (CMB) observations, indicate that the dark energy density changes over time. Here we explore the possibility that the dark energy density is constant, but that the cosmological recombination history differs substantially from that in $\Lambda$CDM. When we free up the ionization history, but otherwise assume the standard cosmological model, we find the combination of CMB and DESI data prefer i) early recombination qualitatively similar to models with small-scale clumping, ii) a value of $H_0$ consistent with the estimate from the SH0ES Collaboration at the $2\sigma$ level, and iii) a higher CMB lensing power, which takes pressure off of otherwise tight constraints on the sum of neutrino masses. Our work provides additional motivation for finding physical models that lead to the small-scale clumping that can theoretically explain the ionization history preferred by DESI and CMB data.

Latitudinal Asymmetry in the Dayside Atmosphere of WASP-43b

Authors: Ryan C. Challener, Zafar Rustamkulov, Elspeth K.H. Lee, Nikole Lewis, David K. Sing, Stephan M. Birkmann, Nicolas Crouzet, Néstor Espinoza, Elena Manjavacas, Natalia Oliveros-Gomez, Jeff A. Valenti, Jingxuan Yang
Subjects: Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Arxiv link: https://arxiv.org/abs/2406.10207
Pdf link: https://arxiv.org/pdf/2406.10207
Abstract We present two-dimensional near-infrared temperature maps of the canonical hot Jupiter WASP-43b using a phase-curve observation with JWST NIRSpec/G395H. From the white-light planetary transit, we improve constraints on the planet's orbital parameters and measure a planet-to-star radius ratio of $0.15883^{+0.00056}{-0.00053}$. Using the white-light phase curve, we measure a longitude of maximum brightness of $6.9^{+0^\circ.5}{-0^\circ.5}$ east of the substellar point and a phase-curve offset of $10.0^{+0^\circ.8}{-0^\circ.8}$. We also find an $\approx4\sigma$ detection of a latitudinal hotspot offset of $-13.4^{+3^\circ.2}{-1^\circ.7}$, the first significant detection of a non-equatorial hotspot in an exoplanet atmosphere. We show that this detection is robust to variations within planetary parameter uncertainties, but only if the transit is used to improve constraints, showing the importance of transit observations to eclipse mapping. Maps retrieved from the NRS1 and NRS2 detectors are similar, with hotspot locations consistent between the two detectors at the $1\sigma$ level. Our JWST data show brighter (hotter) nightsides and a dimmer (colder) dayside at the shorter wavelengths relative to fits to \textit{Spitzer} 3.6 and 4.5 \microns\ phase curves. Through comparison between our phase curves and a set of general circulation models, we find evidence for clouds on the nightside and atmospheric drag or high metallicity reducing the eastward hotspot offset.

by olozhika (Xing Yuchen).

2024-06-18

olozhika / ArXivDaily_StarFormation