1. Protoplanetary disc truncation mechanisms in stellar clusters: comparing external photoevaporation and tidal encounters
- Author
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Jegug Ih, Cathie J. Clarke, Stefano Facchini, Andrew J Winter, Thomas J. Haworth, Giovanni P. Rosotti, Winter, Andrew [0000-0002-7501-9801], Clarke, Catherine [0000-0003-4288-0248], Rosotti, Giovanni [0000-0003-4853-5736], Haworth, Thomas [0000-0002-9593-7618], and Apollo - University of Cambridge Repository
- Subjects
stars: kinematics and dynamics ,BROWN DWARFS ,Population ,FOS: Physical sciences ,Flux ,stars: pre-main-sequence ,LOW-MASS STARS ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astronomy & Astrophysics ,circumstellar matter ,01 natural sciences ,SPITZER C2D SURVEY ,CIRCUMSTELLAR DISKS ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,MAIN-SEQUENCE ,education ,010303 astronomy & astrophysics ,Stellar density ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,SIGMA-ORIONIS ,Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,education.field_of_study ,Science & Technology ,ORION NEBULA CLUSTER ,010308 nuclear & particles physics ,Velocity dispersion ,Astronomy and Astrophysics ,Radius ,Photoevaporation ,Astrophysics - Astrophysics of Galaxies ,protoplanetary discs ,Accretion (astrophysics) ,0201 Astronomical And Space Sciences ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Physical Sciences ,MOLECULAR CLOUDS ,accretion, accretion discs ,SPATIAL-DISTRIBUTION ,Astrophysics::Earth and Planetary Astrophysics ,LAMBDA-ORIONIS ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Most stars form and spend their early life in regions of enhanced stellar density. Therefore the evolution of protoplanetary discs (PPDs) hosted by such stars are subject to the influence of other members of the cluster. Physically, PPDs might be truncated either by photoevaporation due to ultraviolet flux from massive stars, or tidal truncation due to close stellar encounters. Here we aim to compare the two effects in real cluster environments. In this vein we first review the properties of well studied stellar clusters with a focus on stellar number density, which largely dictates the degree of tidal truncation, and far ultraviolet (FUV) flux, which is indicative of the rate of external photoevaporation. We then review the theoretical PPD truncation radius due to an arbitrary encounter, additionally taking into account the role of eccentric encounters that play a role in hot clusters with a 1D velocity dispersion $\sigma_v > 2$ km/s. Our treatment is then applied statistically to varying local environments to establish a canonical threshold for the local stellar density ($n_{c} > 10^4$ pc$^{-3}$) for which encounters can play a significant role in shaping the distribution of PPD radii over a timescale $\sim 3$ Myr. By combining theoretical mass loss rates due to FUV flux with viscous spreading in a PPD we establish a similar threshold for which a massive disc is completely destroyed by external photoevaporation. Comparing these thresholds in local clusters we find that if either mechanism has a significant impact on the PPD population then photoevaporation is always the dominating influence., ERC Advanced Grant grant agreement 341137
- Published
- 2018