Year: 2026
Type: article
Abstract: We report the first detection of TiO in star-forming regions based on Atacama Large Millimeter/submillimeter Array observations of Orion Source I, a well-characterized massive protostar. Multiple rotational transitions are identified, with emission spatially resolved within ∼50 au, showing a compact distribution with a velocity structure consistent with the base of a rotating outflow. The spatial and velocity distributions of TiO are consistent with those of AlO, with both species being key dust-seeding refractory molecules. The column density of TiO is derived to be (3.0 ± 0.4) × 10 15 cm −2 , corresponding to X TiO/SiO ∼ 12.8 ± 1.7 × 10 −3 , higher than the CI chondrite X Ti/Si value and indicative of efficient dust-to-gas conversion near the protostar. The detection of TiO, a key dust-seeding species, offers important constraints on refractory chemistry and the formation environments of primitive minerals, linking astrochemical processes in protostellar systems to the earliest stages of solar system material formation.
Institutions: RIKEN Pioneering Research Institute, Instituto de Física Fundamental, National Institute for Astrophysics, The Graduate University for Advanced Studies, SOKENDAI, National Astronomical Observatory of Japan, University of Florida, National Radio Astronomy Observatory, Massachusetts Institute of Technology, Universidad Nacional Autónoma de México, Herzberg Institute of Astrophysics, Kyoto University, The University of Tokyo, Institute of Science Tokyo, Shanghai Jiao Tong University, Shanghai Key Laboratory for Particle Physics and Cosmology, Centro de Astrobiología
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Award: G8895903295
OpenAlex ID: W7172437579