JWST/MIRI Spectroscopy of the Disk of the Young Eruptive Star EX Lup in Quiescence

Abstract

EX Lup is a low-mass pre-main sequence star that occasionally shows accretion-related outbursts. Here, we present JWST/MIRI medium resolution spectroscopy obtained for EX Lup fourteen years after its powerful outburst. EX Lup is now in quiescence and displays a Class II spectrum. We detect a forest of emission lines from molecules previously identified in infrared spectra of classical T Tauri disks: H2O, OH, H2, HCN, C2H2, and CO2. The detection of organic molecules demonstrates that they are back after disappearing during the large outburst. Spectral lines from water and OH are for the first time de-blended and will provide a much improved characterization of their distribution and density in the inner disk. The spectrum also shows broad emission bands from warm, sub-micron size amorphous silicate grains at 10 and 18 um. During the outburst, in 2008, crystalline forsterite grains were annealed in the inner disk within 1 au, but their spectral signatures in the 10 um silicate band later disappeared. With JWST we re-discovered these crystals via their 19.0, 20.0, and 23.5 um emission, whose strength implies that the particles are at ~3 au from the star. This suggests that crystalline grains formed in 2008 were transported outwards and now approach the water snowline, where they may be incorporated into planetesimals. Containing several key tracers of planetesimal and planet formation, EX Lup is an ideal laboratory to study the effects of variable luminosity on the planet-forming material and may provide explanation for the observed high crystalline fraction in solar system comets.

arXiv comment9 pages, 4 figures, accepted for publication in ApJL. JWST/MIRI spectrum is available for download at https://tinyurl.com/spexodisksJWST

References in corpus (35)

• Protoplanetary Disks and Their Evolution
• A Survey and Analysis of Spitzer Infrared Spectrograph Spectra of T Tauri Stars in Taurus
• The c2d Spitzer Spectroscopic Survey of Ices Around Low-Mass Young Stellar Objects: I. H2O and the 5-8 um Bands
• Consistent dust and gas models for protoplanetary disks. I. Disk shape, dust settling, opacities, and PAHs
• Modeling optical properties of cosmic dust grains using a distribution of hollow spheres
• ISO spectroscopy of gas and dust: from molecular clouds to protoplanetary disks
• Astrochemistry During the Formation of Stars
• C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth
• A Spitzer survey of mid-infrared molecular emission from protoplanetary disks I: Detection rates
• Imaging the water-snow line during a protostellar outburst
• A Spitzer Survey of Mid-Infrared Molecular Emission from Protoplanetary Disks II: Correlations and LTE Models
• A Spitzer IRS Study of Infrared Variability in Transitional and Pre-Transitional Disks around T Tauri Stars
• Episodic formation of cometary material in the outburst of a solar-like young star
• Organic Molecules and Water in the Inner Disks of T Tauri Stars
• c2d Spitzer IRS Spectra of Disks around T Tauri Stars. III. [Ne II], [Fe I], and H_2 gas-phase lines
• GASPS - a Herschel survey of gas and dust in Protoplanetary Disks: Summary and Initial Statistics
• DIGIT survey of far-infrared lines from protoplanetary disks I
• The full infrared spectrum of molecular hydrogen
• Atmospheres of Rocky Exoplanets
• Evidence for Dynamical Changes in a Transitional Protoplanetary Disk with Mid-infrared Variability
• Ex Lupi from Quiescence to Outburst: Exploring the LTE Approach in Modelling Blended H2O and OH Mid-Infrared Emission
• The 2008 outburst of EX Lup - silicate crystals in motion
• On the nature of the EXor accretion events: an unfrequent manifestation of a common phenomenology ?
• EX Lupi in quiescence
• Scanning disk rings and winds in CO at 0.01-10 au: a high-resolution $M$-band spectroscopy survey with IRTF-iSHELL
• The TEXES Survey For H2 Emission From Protoplanetary Disks
• Chemical Signatures of the FU Ori Outbursts
• The chemistry of episodic accretion in embedded objects. 2D radiation thermo-chemical models of the post-burst phase
• The kinematics and excitation of infrared water vapor emission from planet-forming disks: results from spectrally-resolved surveys and guidelines for JWST spectra
• Mid-Infrared Spectral Variability Atlas of Young Stellar Objects
• Fundamental Vibrational Transition of CO during the Outburst of EX Lupi in 2008
• Depletion of molecular gas by an accretion outburst in a protoplanetary disk
• Chemical evolution in ices on drifting, planet-forming pebbles
• The Highly Dynamic Behavior of the Innermost Dust and Gas in the Transition Disk Variable LRLL 31
• Spectral evolution and radial dust transport in the prototype young eruptive system EX Lup

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