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arXiv · 2509.01896

ALMA High-resolution Observation for the Transitional Disk around IRAS 04125+2902

Ayumu Shoshi·Takayuki Muto·Quincy Bosschaart·Nienke van der Marel·Gijs D. Mulders·Mitsuki Omura·Kazuki Tokuda·Masahiro N. Machida
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Abstract

Recently, the youngest transiting planet was discovered around the T Tauri star, IRAS 04125+2902, in the Taurus-Auriga star-forming region. This system is crucial for understanding the early stages of planet formation. We used Atacama Large Millimeter/submillimeter Array Band 6 data to investigate the IRAS 04125+2902 system in detail. The dust continuum emission reveals a ring-gap transitional disk structure with an inclination of 35.6$^{\circ}$. In addition, two-dimensional super-resolution imaging based on Sparse Modeling and the one-dimensional modeling of disk brightness distribution suggest the existence of an inner emission, which may be attributed to an inner disk, although free-free emission from the central star is not ruled out. Furthermore, we identified the $^{12}$CO $J$=2-1 emission, and the dynamical mass of the central star is estimated to be 0.7-1.0 $M_{\odot}$. The asymmetry of the dust ring and the velocity distortion around the central star are, if at all, weak, suggesting that the inner disk, if it exists, is not highly inclined with respect to the outer disk. Radiative transfer calculations of dust continuum emission suggest that the inner and the outer disk may be misaligned by $\sim$10$^\circ$, which may be confirmed in future observations with higher resolution and sensitivity. Our results suggest that IRAS 04125+2902 is a dynamically complex system, where the binary orbit, outer disk, inner disk, and planetary orbit are mutually misaligned, providing insight into the early orbital evolution of young systems.

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Ayumu Shoshi, Takayuki Muto, Quincy Bosschaart, Nienke van der Marel, Gijs D. Mulders, Mitsuki Omura, Kazuki Tokuda, Masahiro N. Machida. 2025-09-02. ALMA High-resolution Observation for the Transitional Disk around IRAS 04125+2902. https://arxiv.org/abs/2509.01896

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