182 research outputs found
PENELLOPE: The ESO data legacy program to complement the <i>Hubble</i> UV Legacy Library of Young Stars (ULLYSES). I:Survey presentation and accretion properties of Orion OB1 and Ï-Orionis
Effects of photoevaporation on protoplanetary disc ‘isochrones’
Protoplanetary discs are the site of star and planet formation, and their evolution and consequent dispersal deeply affect the formation of planetary systems. In the standard scenario they evolve on time-scales similar to Myr due to the viscous transport of angular momentum. The analytical self-similar solution for their evolution predicts specific disc isochrones in the accretion rate-disc mass plane. However, photoevaporation by radiation emitted by the central star is likely to dominate the gas disc dispersal of the innermost region, introducing another (shorter) time-scale for this process. In this paper, we include the effect of internal (X and EUV) photoevaporation on the disc evolution, finding numerical solutions for a population of protoplanetary discs. Our models naturally reproduce the expected quick dispersal of the inner region of discs when their accretion rates match the rate of photoevaporative mass loss, in line with previous studies. We find that photoevaporation preferentially removes the lightest discs in the sample. The net result is that, counter-intuitively, photoevaporation increases the average disc mass in the sample, by dispersing the lightest discs. At the same time, photoevaporation also reduces the mass accretion rate by cutting the supply of material from the outer to the inner disc. In a purely viscous framework, this would be interpreted as the result of a longer viscous evolution, leading to an overestimate of the disc age. Our results thus show that photoevaporation is a necessary ingredient to include when interpreting observations of large disc samples with measured mass accretion rates and disc masses. Photoevaporation leaves a characteristic imprint on the shape of the isochrone. Accurate data of the accretion rate-disc mass plane in the low disc mass region therefore give clues on the typical photoevaporation rate
Constraining disk evolution prescriptions of planet population synthesis models with observed disk masses and accretion rates
While planets are commonly discovered around main-sequence stars, the processes leading to their formation are still far from being understood. Current planet population synthesis models, which aim to describe the planet formation process from the protoplanetary disk phase to the time exoplanets are observed, rely on prescriptions for the underlying properties of protoplanetary disks where planets form and evolve. The recent development in measuring disk masses and disk-star interaction properties, i.e., mass accretion rates, in large samples of young stellar objects demand a more careful comparison between the models and the data. We performed an initial critical assessment of the assumptions made by planet synthesis population models by looking at the relation between mass accretion rates and disk masses in the models and in the currently available data. We find that the currently used disk models predict mass accretion rate in line with what is measured, but with a much lower spread of values than observed. This difference is mainly because the models have a smaller spread of viscous timescales than what is needed to reproduce the observations. We also find an overabundance of weakly accreting disks in the models where giant planets have formed with respect to observations of typical disks. We suggest that either fewer giant planets have formed in reality or that the prescription for planet accretion predicts accretion on the planets that is too high. Finally, the comparison of the properties of transition disks with large cavities confirms that in many of these objects the observed accretion rates are higher than those predicted by the models. On the other hand, PDS70, a transition disk with two detected giant planets in the cavity, shows mass accretion rates well in line with model predictions
Constraining the radial drift of millimeter-sized grains in the protoplanetary disks in Lupus
The ALMA Lupus protoplanetary disk survey:evidence for compact gas disks and molecular rings from CN
The relation between the mass accretion rate and the disk mass in Class I Protostars
Interstellar matter and star formatio
Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS):Scattered light detection of a possible disk wind in RY Tau
"Reading between the lines'': magnetospheric accretion, winds, and the inner disk
Stars and planetary system
HST Survey of the Orion Nebula Cluster in the H2O 1.4 ÎŒm Absorption Band:I. A Census of Substellar and Planetary-mass Objects
Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS):Late Infall Causing Disk Misalignment and Dynamic Structures in SU Aur
Gas-rich circumstellar disks are the cradles of planet formation. As such,
their evolution will strongly influence the resulting planet population. In the
ESO DESTINYS large program, we study these disks within the first 10 Myr of
their development with near-infrared scattered light imaging. Here we present
VLT/SPHERE polarimetric observations of the nearby class II system SU Aur in
which we resolve the disk down to scales of ~7 au. In addition to the new
SPHERE observations, we utilize VLT/NACO, HST/STIS and ALMA archival data. The
new SPHERE data show the disk around SU Aur and extended dust structures in
unprecedented detail. We resolve several dust tails connected to the Keplerian
disk. By comparison with ALMA data, we show that these dust tails represent
material falling onto the disk. The disk itself shows an intricate spiral
structure and a shadow lane, cast by an inner, misaligned disk component. Our
observations suggest that SU Aur is undergoing late infall of material, which
can explain the observed disk structures. SU Aur is the clearest observational
example of this mechanism at work and demonstrates that late accretion events
can still occur in the class II phase, thereby significantly affecting the
evolution of circumstellar disks. Constraining the frequency of such events
with additional observations will help determine whether this process is
responsible for the spin-orbit misalignment in evolved exoplanet systems.Comment: 18 pages, 12 figures, published in ApJL on 18-02-202
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