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— Centroid in pixels versus velocities in the stellocentric frame for the parallel (left panel) and anti-parallel (right panel) slit orientations. The color coding is as follows: black for 0 and 180 @BULLET , red for 270 and 90 @BULLET , green for 333 and 153 @BULLET , and blue for 63 and 243 @BULLET .
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![Fig. 2.— The five flux calibrated spectra of TW Hya around the [Ne ii]...](profile/Silvia-Alencar/publication/230967871/figure/fig2/AS:393455567163398@1470818525636/The-five-flux-calibrated-spectra-of-TW-Hya-around-the-Ne-ii-emission-line-The-x-axis_Q320.jpg)
Photoevaporation driven by the central star is expected to be a ubiquitous and important mechanism for dispersing the circumstellar dust and gas from which planets form. Here, we present a detailed study of the circumstellar disk surrounding the nearby star TW Hya and provide observational constraints to its photoevaporative wind. Our new high-reso...
Citations
... This also shows a blueshift (Herczeg et al. 2007;Pascucci & Sterzik 2009) and usually shows either an HVC or a single narrow LVC (Baldovin-Saavedra et al. 2012;Sacco et al. 2012;Pascucci et al. 2020), the latter suggesting an origin further out in the disk than [O I]. This scenario is also supported by the fact that it remains blueshifted even in disks with large cavities where the [O I] emission may have much smaller or no blueshift (e.g., TW Hya; Pascucci et al. 2011;Fang et al. 2023), and therefore likely has to originate further out, outside the cavity. Further evidence that the [Ne II] traces wind material distinct to that traced by the [O I] is that the former gets brighter as the spectral index between 13 and 31 μm increases (which indicates the clearing of dust from the inner disk), while latter gets fainter (Pascucci et al. 2020). ...
... In such a model, the column density is accumulated at small radii for b > 1 and large radii for b 1. We focus on b = 1.5, a value motivated both by theory/simulations (Hollenbach et al. 1994;Picogna et al. 2019) as well as previous comparisons to observations of TW Hya (Pascucci et al. 2011;Ballabio et al. 2020). Note that this is also the scaling adopted in various self-similar magnetized wind models (Blandford & Payne 1982;Lesur 2021). ...
... 11 We compare them to the R = 45,000 profile analyzed by Pascucci et al. (2020). While the models without a dust cavity in this case overpredict the blueshift, the presence of a cavity makes them consistent with the very low observed blueshift of the [O I] line (as argued for TW Hya by Pascucci et al. 2011). Moreover, with or without a cavity, since in all cases the emission is constrained to the hottest inner parts of the wind, there is an even stronger dependence of the FHWM on r in . ...
Ne ii ] 12.81 μ m emission is a well-used tracer of protoplanetary disk winds due to its blueshifted line profile. Mid-Infrared Instrument (MIRI)-Medium Resolution Spectrometer (MRS) recently observed T Cha, detecting this line along with lines of [Ne iii ], [Ar ii ], and [Ar iii ], with the [Ne ii ] and [Ne iii ] lines found to be extended while the [Ar ii ] was not. In this complementary work, we use these lines to address long-debated questions about protoplanetary disk winds regarding their mass-loss rate, the origin of their ionization, and the role of magnetically driven winds as opposed to photoevaporation. To this end, we perform photoionization radiative transfer on simple hydrodynamic wind models to map the line emission. We compare the integrated model luminosities to those observed with MIRI-MRS to identify which models most closely reproduce the data and produce synthetic images from these to understand what information is captured by measurements of the line extents. Along with the low degree of ionization implied by the line ratios, the relative compactness of [Ar ii ] compared to [Ne ii ] is particularly constraining. This requires Ne ii production by hard X-rays and Ar ii production by soft X-rays (and/or EUV) in an extended (≳10 au) wind that is shielded from soft X-rays, necessitating a dense wind with material launched on scales down to ∼1 au. Such conditions could be produced by photoevaporation, whereas an extended magnetohydrodynamic (MHD) wind producing equal shielding would likely underpredict the line fluxes. However, a tenuous inner MHD wind may still contribute to shielding the extended wind. This picture is consistent with constraints from spectrally resolved line profiles.
... The CO model has a temperature and column density of T = 1500 K and N log 17.5 = cm −2 , and the rotational H 2 O emission lines are consistent with T = 850 K and N log 15.0 = . The rovibrational lines are shown with the rotational model scaled down by a factor of 20 in flux.High-resolution spectroscopic studies of mid-IR [Ne II] emission typically detect either a high-velocity component (HVC) associated with collimated jets or a low-velocity component (LVC) tracing either MHD or photoevaporative disk winds in the 1D emission line profiles(Herczeg et al. 2007;Güdel et al. 2010;Pascucci et al. 2011;Alexander et al. 2014;Pascucci et al. 2020) and 2D line images(Bajaj et al. 2024). Although the MIRI MRS observations do not have the ...
We present JWST MIRI MRS observations of the edge-on protoplanetary disk around the young subsolar-mass star Tau 042021, acquired as part of the Cycle 1 GO program “Mapping Inclined Disk Astrochemical Signatures.” These data resolve the mid-IR spatial distributions of H 2 , revealing X-shaped emission extending to ∼200 au above the disk midplane with a semiopening angle of 35° ± 5°. We do not velocity-resolve the gas in the spectral images, but the measured semiopening angle of the H 2 is consistent with a magnetohydrodynamic wind origin. A collimated, bipolar jet is seen in forbidden emission lines from [Ne ii ], [Ne iii ], [Ni ii ], [Fe ii ], [Ar ii ], and [S iii ]. Extended H 2 O and CO emission lines are also detected, reaching diameters of ∼90 and 190 au, respectively. Hot molecular emission is not expected at such radii, and we interpret its extended spatial distribution as scattering of inner disk molecular emission by dust grains in the outer disk surface. H i recombination lines, characteristic of inner disk accretion shocks, are similarly extended and are likely also scattered light from the innermost star–disk interface. Finally, we detect extended polycyclic aromatic hydrocarbon (PAH) emission at 11.3 μ m cospatial with the scattered-light continuum, making this the first low-mass T Tauri star around which extended PAHs have been confirmed, to our knowledge. MIRI MRS line images of edge-on disks provide an unprecedented window into the outflow, accretion, and scattering processes within protoplanetary disks, allowing us to constrain the disk lifetimes and accretion and mass-loss mechanisms.
... In another survey using high-resolution spectroscopy, Pascucci et al. (2020) modeled the [O I] λ6300 low velocity from several transition disks and showed that most of the emission is coming from within ∼1-2 au. More recently, Fang et al. (2023b) spatially resolved the [O I] λ6300 emission from TW Hya and showed that 80% comes from within 1 au of the star, in agreement with previous inferences based on modeling spectrally resolved [O I] profiles (Pascucci et al. 2011(Pascucci et al. , 2020. The small emitting radius in TW Hya as well as in other sources, combined with blueshifts in the line centroids, are difficult to reconcile with the PE wind scenario (but see Rab et al. 2023), and [O I] is therefore more frequently interpreted as tracing an MHD disk wind (e.g., Simon et al. 2016;Banzatti et al. 2019;Fang et al. 2023a). ...
... Disks with inner dust cavities show singly peaked [Ne II] profiles with modest widths (FWHM ∼ 15-40 km s −1 ) and small blueshifts (∼3-6 km s −1 ) relative to the stellar systemic velocity (Pascucci & Sterzik 2009;Sacco et al. 2012) that are consistent with the PE wind model predictions (Alexander 2008). Additionally, the absence of the redshifted component of [Ne II] suggests that there is dust in the midplane, which blocks our view of the receding wind (Alexander 2008;Ercolano & Owen 2010;Pascucci et al. 2011), and that the emission originates largely outside the dust hole. ...
... To reiterate, T Cha has a large dust gap (Hendler et al. 2018), and its [Ne II] emission shows a blueshift (Pascucci & Sterzik 2009;Sacco et al. 2012). This means that our view of the redshifted emission is blocked by either the very small inner dust disk (<1 au) or the outer disk (∼25 au; e.g., Ercolano & Owen 2010;Pascucci et al. 2011). If the [Ne II] emission was spatially compact, then it would have eliminated its possibility of tracing a PE wind, but as we have seen in Sections 3.2.1 and 3.2.2, the [Ne II] emission is extended beyond the PSF and hence resolved. ...
Understanding when and how circumstellar disks disperse is crucial to constrain planet formation and migration. Thermal winds powered by high-energy stellar photons have long been theorized to drive disk dispersal. However, evidence for these winds is currently based only on small (∼3–6 km s ⁻¹ ) blueshifts in [Ne ii ] 12.81 μ m lines, which does not exclude MHD winds. We report JWST MIRI MRS spectro-imaging of T Cha, a disk with a large dust gap (∼30 au in radius) and blueshifted [Ne ii ] emission. We detect four forbidden noble gas lines, [Ar ii ], [Ar iii ], [Ne ii ], and [Ne iii ], of which [Ar iii ] is the first detection in any protoplanetary disk. We use line flux ratios to constrain the energy of the ionizing photons and find that argon is ionized by extreme ultraviolet, whereas neon is most likely ionized by X-rays. After performing continuum and point-spread function subtraction on the integral field unit cube, we discover a spatial extension in the [Ne ii ] emission off the disk continuum emission. This is the first spatially resolved [Ne ii ] disk wind emission. The mostly ionic spectrum of T Cha, in combination with the extended [Ne ii ] emission, points to an evolved stage for any inner MHD wind and is consistent with the existence of an outer thermal wind ionized and driven by high-energy stellar photons. This work acts as a pathfinder for future observations aiming at investigating disk dispersal using JWST.
... On the one hand, a vortex generated by a planet(s) inside the cavity will create an observable azimuthal shift in the dust millimeter emission (Baruteau & Zhu 2016), while it is still unclear if that is the case in the dead zone case. On the other hand, disk winds can be detected through broad (>5 km s −1 ) molecular and atomic lines (e.g., Pascucci et al. 2011;Klaassen et al. 2013Klaassen et al. , 2016Booth et al. 2021). Therefore, with high-spatial-resolution observations of gas and dust emission at different wavelengths, it is possible to start ruling out one or more of the proposed mechanisms toward specific systems. ...
While the most exciting explanation of the observed dust asymmetries in protoplanetary disks is the presence of protoplanets, other mechanisms can also form the dust features. This paper presents dual-wavelength Atacama Large Millimeter/submillimeter Array observations of a large asymmetric dusty ring around the M-type star CIDA 9A. We detect a dust asymmetry in both 1.3 and 3.1 mm data. To characterize the asymmetric structure, a parametric model is used to fit the observed visibilities. We report a tentative azimuthal shift of the dust emission peaks between the observations at the two wavelengths. This shift is consistent with a dust trap caused by a vortex, which may be formed by an embedded protoplanet or other hydrodynamical instabilities, such as a dead zone. Deep high-spatial-resolution observations of dust and molecular gas are needed to constrain the mechanisms that formed the observed millimeter cavity and dust asymmetry in the protoplanetary disk around CIDA 9A.
... However, comparing observations and theories has not led to clear results. High-resolution groundbased observations of the [Ne II] line are fit equally well by different photoevaporation models (e.g., Pascucci et al. 2011). ...
We report the first detection of variability in the mid-infrared neon line emission of a protoplanetary disk by comparing a JWST Mid-InfraRed Instrument Medium Resolution Spectrometer spectrum of SZ Cha taken in 2023 with a Spitzer Infrared Spectrograph Short-High spectrum of this object from 2008. We measure the [Ne iii ]-to-[Ne ii ] line flux ratio, which is a diagnostic of the high-energy radiation field, to distinguish between the dominance of EUV- or X-ray-driven disk photoevaporation. We find that the [Ne iii ]-to-[Ne ii ] line flux ratio changes significantly from ∼1.4 in 2008 to ∼0.2 in 2023. This points to a switch from EUV-dominated to X-ray-dominated photoevaporation of the disk. We present contemporaneous ground-based optical spectra of the H α emission line that show the presence of a strong wind in 2023. We propose that this strong wind prevents EUV radiation from reaching the disk surface while the X-rays permeate the wind and irradiate the disk. We speculate that at the time of the Spitzer observations, the wind was suppressed and EUV radiation reached the disk. These observations confirm that the MIR neon emission lines are sensitive to changes in high-energy radiation reaching the disk surface. This highlights the [Ne iii ]-to-[Ne ii ] line flux ratio as a tool to gauge the efficiency of disk photoevaporation in order to provide constraints on the planet formation timescale. However, multiwavelength observations are crucial to interpret the observations and properly consider the star–disk connection.
... We also compare our model with the observations of the [Ne II] 12.8 μm line presented in Pascucci et al. (2011). For this line, we simply produce spectral line profiles, again using both postprocessing approaches. ...
... As [Ne II] 12.8 μm traces regions further out and higher up (up to r ≈ 10 au) in the disk/wind with respect to [O I] 6300 Å, it traces higher velocities of the photoevaporative flow (see Figure 3), consistent with the observed v c ≈ −5 km s −1 . The line luminosity of the models is 3.4 × 10 −6 L ☉ (MOCASSIN) and 5.1 × 10 −6 L ☉ (PRODIMO), which are in excellent agreement with the observed range of luminosities of ≈3.5-6.2 × 10 −6 L ☉ (Pascucci & Sterzik 2009;Najita et al. 2010;Pascucci et al. 2011). ...
... As already noted in Pascucci et al. (2011) and also discussed in Fang et al. (2023), the [Ne II] 12.8 μm line observation points toward a thermally driven wind. This is supported by the models presented in this work, as the agreement of the PE wind model with the spectral line profile and the observed line fluxes (which is underpredicted by a factor of 3 by the MHD model of Fang et al. 2023) is excellent, indicating that at least for the radii larger than a few astronomical units, traced by the [Ne II] 12.8 μm line, the disk wind structure of TW Hya is predominantly shaped by a PE flow. ...
Theoretical models indicate that photoevaporative and magnetothermal winds play a crucial role in the evolution and dispersal of protoplanetary disks and affect the formation of planetary systems. However, it is still unclear what wind-driving mechanism is dominant or if both are at work, perhaps at different stages of disk evolution. Recent spatially resolved observations by Fang et al. of the [O i ] 6300 Å spectral line, a common disk wind tracer in TW Hya, revealed that about 80% of the emission is confined to the inner few astronomical units of the disk. In this work, we show that state-of-the-art X-ray-driven photoevaporation models can reproduce the compact emission and the line profile of the [O i ] 6300 Å line. Furthermore, we show that the models also simultaneously reproduce the observed line luminosities and detailed spectral profiles of both the [O i ] 6300 Å and the [Ne ii ] 12.8 μ m lines. While MHD wind models can also reproduce the compact radial emission of the [O i ] 6300 Å line, they fail to match the observed spectral profile of the [O i ] 6300 Å line and underestimate the luminosity of the [Ne ii ] 12.8 μ m line by a factor of 3. We conclude that, while we cannot exclude the presence of an MHD wind component, the bulk of the wind structure of TW Hya is predominantly shaped by a photoevaporative flow.
... We also compare our model with the observations of the [NeII] 12.8 µm line presented in Pascucci et al. (2011). For this line we simply produce spectral line profiles again using both post-processing approaches. ...
... As [NeII] 12.8 µm traces regions further out and higher up (up to r ≈ 10 au) in the disk/wind with respect to [OI] 6300Å , it traces higher velocities of the photoevaporative flow (see Fig. 3), consistent with the observed v c ≈ −5 kms −1 . The line luminosity of the models is 3.4 × 10 −6 L ⊙ (MOCASSIN) and 5.1 × 10 −6 L ⊙ (PRODIMO ) which are in excellent agreement with the observed range of luminosities of ≈ 3.5 − 6.2 × 10 −6 L ⊙ (Pascucci et al. 2011;Pascucci & Sterzik 2009;Najita et al. 2010). ...
... We show here, however, that, compared to the fiducial magneto-thermal wind model presented in Fang et al. (2023), modern PE models produce only very slightly more extend [OI] 6300Å emission but are still fully consistent with the data. Apart from the higher inner grid (Simon et al. 2016;Fang et al. 2018Fang et al. , 2023 and [NeII] 12.8 µm (Pascucci et al. 2011) spectral line profiles to synthetic line profiles of photoevaporative disk wind models. The [OI] line profiles from the models and that observed by Fang et al. (2023) have been degraded to a resolving power R = 40000, comparable to the resolution in the observation by Simon et al. (2016). ...
Theoretical models indicate that photoevaporative and magnetothermal winds play a crucial role in the evolution and dispersal of protoplanetary disks and affect the formation of planetary systems. However, it is still unclear what wind-driving mechanism is dominant or if both are at work, perhaps at different stages of disk evolution. Recent spatially resolved observations by Fang et al. (2023) of the [OI] 6300 Angstrom spectral line, a common disk wind tracer, in TW Hya revealed that about 80% of the emission is confined to the inner few au of the disk. In this work, we show that state-of-the-art X-ray driven photoevaporation models can reproduce the compact emission and the line profile of the [OI] 6300 Angstrom line. Furthermore, we show that the models also simultaneously reproduce the observed line luminosities and detailed spectral profiles of both the [OI] 6300 Angstrom and the [NeII] 12.8 micron lines. While MHD wind models can also reproduce the compact radial emission of the [OI] 6300 Angstrom line, they fail to match the observed spectral profile of the [OI] 6300 Angstrom line and underestimate the luminosity of the [NeII] 12.8 micron line by a factor of three. We conclude that, while we cannot exclude the presence of an MHD wind component, the bulk of the wind structure of TW Hya is predominantly shaped by a photoevaporative flow.
... At larger radii (>10 AU), by contrast, observations of turbulent velocities and dust settling both typically yield much lower values, ≲ 10 −3 (Flaherty et al. 2018(Flaherty et al. , 2020Teague et al. 2018;Dullemond et al. 2018), and the apparent lack of viscous spreading implies a similarly low (Trapman et al. 2020;Long et al. 2022). Magnetised winds with high mass-loss rates are detected through both molecular (e.g., de Valon et al. 2020;Booth et al. 2021) and atomic (e.g., Banzatti et al. 2019;Whelan et al. 2021) tracers, while in other systems we see clear evidence of photoevaporative mass-loss (e.g., Pascucci et al. 2011), especially from more evolved discs (Pascucci et al. 2020). However, how the mass-loss in these winds varies with both radius and time remains highly uncertain (Pascucci et al. 2022). ...
We show that the distribution of observed accretion rates is a powerful diagnostic of protoplanetary disc physics. Accretion due to turbulent ("viscous") transport of angular momentum results in a fundamentally different distribution of accretion rates than accretion driven by magnetised disc winds. We find that a homogeneous sample of $\gtrsim$300 observed accretion rates would be sufficient to distinguish between these two mechanisms of disc accretion at high confidence, even for pessimistic assumptions. Current samples of T Tauri star accretion rates are not this large, and also suffer from significant inhomogeneity, so both viscous and wind-driven models are broadly consistent with the existing observations. If accretion is viscous, the observed accretion rates require low rates of disc photoevaporation ($\lesssim$$10^{-9}$M$_{\odot}$yr$^{-1}$). Uniform, homogeneous surveys of stellar accretion rates can therefore provide a clear answer to the long-standing question of how protoplanetary discs accrete.
... The [O I] λ6,300 emission line from TW Hya is narrow (full-width at half-maximum (FWHM) of ~13.0 km s −1 ) with a small blueshift 9,19-21 , measured here with a mean of −0.8 ± 0.4 km s −1 (Extended Data Figs. 1 and 2). The spectroscopic comparison with blueshifted [Ne II] emission leads to the inference that the [O I] emission is likely to be more compact and may even originate in the disk and not from a wind 19,22 . Figure 1a shows the error-weighted mean [O I] λ6,300 intensity map of TW Hya with MUSE (see Methods for a detailed description and Extended Data Fig. 3 ...
... The model produces ~1.2 × 10 −5 L ⊙ in the [O I] line, which is consistent with the observed luminosity of ~1.5 × 10 −5 L ⊙ . The hole in the inner disk allows some of emission on the back side of the disk to be detected, which will decrease the centroid velocity from our generic full disk model 19,22 . ...
... The [Ne II] emission line should trace different spatial regions in the winds, as it peaks at slightly outer radii (~1 au) and higher altitudes in the magnetothermal wind models. Nonetheless, the model [Ne II] emission exhibits strong agreement with the observed line profile 19 with a luminosity three times weaker than measured 18 (Extended Data Fig. 2). ...
Disk winds are thought to play a critical role in the evolution and dispersal of protoplanetary disks. A primary diagnostic of this physics is emission from the wind, especially in the low-velocity component of the [O I] λ6,300 line. However, the interpretation of the line is usually based on spectroscopy alone, which leads to confusion between magnetohydrodynamic winds and photoevaporative winds. Here we report that in high-resolution spectral mapping of TW Hya by the multi-unit spectroscopic explorer at the Very Large Telescope, 80% of the [O I] emission is confined to within 1 au radially from the star. A generic model of a magnetothermal wind produces [O I] emission at the base of the wind that broadly matches the flux and the observed spatial and spectral profiles. The emission at large radii is much fainter than predicted from models of photoevaporation, perhaps because the magnetothermal wind partially shields the outer disk from energetic radiation from the central star. This result calls into question the previously assessed importance of photoevaporation in disk dispersal predicted by models.
... High-resolution ALMA observations reveals an inner cavity of AU in the distribution of mm-sized dust grains 15 ; a similar cavity in small dust grains is measured from the deficit in near-and mid-IR emission 16 , although some small grains are located near the disk truncation radius 17 . Blueshifted [Ne II] emission from TW Hya must arise beyond the dust cavity and may indicate the presence of a photoevaporative flow 18 The spectroscopic comparison with blueshifted [Ne II] emission leads to the inference that the [O I] emission is likely more compact and may even originate in the disk and not a wind 19,22 . Figure 1. ...
... The [Ne II] line profile 19 is well reproduced by the generic magnetothermal disk wind model, without any fine tuning to actual disk properties of TW Hya. However, the observed flux is three times stronger than the model flux 18 . ...
... The model produces ∼ 1.2 × 10 −5 L in the [O I] line, which is consistent with the observed luminosity of ∼ 1.5 × 10 −5 L . The hole in the inner disk allows some of emission on the back side of the disk to be detected, which will decrease the centroid velocity from our generic full disk model19,22 .The [Ne II] emission line should trace different spatial regions in the winds, as it peaks at slightly outer radii (∼ 1 AU) and higher altitudes in the magnetothermal wind models. Nonetheless, the model [Ne II] emission exhibits strong agreement with the observed line profile19 with a luminosity three times weaker than measured 18 (see Extended DataFigure 2).The spatially compact emission region is explained by the magnetothermal winds rather than photoevaporation. ...
Disk winds are thought to play a critical role in the evolution and dispersal of protoplanetary disks. The primary diagnostic of this physics is emission from the wind, especially in the low-velocity component of the [O I] $\lambda6300$ line. However, the interpretation of the line is usually based on spectroscopy alone, which leads to confusion between magnetohydrodynamic winds and photoevaporative winds. Here, we report that in high-resolution VLT/MUSE spectral mapping of TW~Hya, 80 % of the [O ] emission is confined to within 1 AU radially from the star. A generic model of a magnetothermal wind produces [O I] emission at the base of the wind that broadly matches the flux and the observed spatial and spectral profiles. The emission at large radii is much fainter that predicted from models of photoevaporation, perhaps because the magnetothermal wind partially shields the outer disk from energetic radiation from the central star. This result calls into question the assumed importance of photoevaporation in disk dispersal predicted by models.
