Understanding the water snowline in low-mass young stellar objects (YSOs) is crucial for comprehending the processes that influence planet formation. The water snowline is the boundary within a protoplanetary disk where water transitions from gas to ice, and its location can significantly affect dust grain growth and chemical composition. This research utilizes radiative transfer models to derive relationships between the water snowline and luminosity, a method that aligns with current observational data.
The study proposes that the water snowline can be estimated through a relationship dependent on the total luminosity of the YSO. The researchers employed various density structures to analyze different models, including an envelope-only model, an envelope with disk and cavity, and a dedicated protoplanetary disk model. They established a power-law relationship between the water snowline, where the dust temperature reaches 100 K, and the total luminosity spanning a range from 0.1 to 1,000 solar luminosities.
The findings indicate that the coefficient in this relationship decreases as the disk density increases. Meanwhile, the power index remains approximately 0.5 across all tested models. As the density of the dust increases, the water snowline is found to occur at smaller radii, even under similar luminosity conditions, due to the reduced propagation of photons through dense dust.
Additionally, the study examines the role of viscous heating on the water snowline”s position. In the protoplanetary disk model, the presence of viscous heating can shift the water snowline outward by several astronomical units, up to 15 AU, which modifies the relationship coefficient and the power index. Conversely, in the envelope plus disk model with lower mass, the impact of viscous heating appears minimal, suggesting that the disk”s mass significantly influences these dynamics.
The variations between the model predictions and direct observations offer valuable insights regarding recent outburst events and the underlying disk structure in low-mass YSOs. This research by Young-Jun Kim and colleagues contributes to a deeper understanding of the complex interactions at play in star formation and the evolution of planetary systems.
