Dust-seeding Molecules in a Massive Protostar—Detection of TiO in Orion Source I
16 affiliations
- 1RIKEN Pioneering Research Institute
- 2Instituto de Física Fundamental
- 3INAF
- 4The Graduate University for Advanced Studies
- 5National Astronomical Observatory of Japan
- 6University of Florida
- 7Massachusetts Institute of Technology
- 8National Radio Astronomy Observatory
- 9Universidad Nacional Autónoma de México
- 10NRC Herzberg Astronomy and Astrophysics
- 11Kyoto University
- 12The University of Tokyo
- 13Institute of Science Tokyo
- 14Shanghai Jiao Tong University
- 15Key Laboratory for Particle Astrophysics and Cosmology (MOE)/Shanghai Key Laboratory for Particle Physics and Cosmology
- 16Centro de Astrobiología (CAB, CSIC-INTA)
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.
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BibTeX
@article{zhang2026dustseeding,
title = {{Dust-seeding Molecules in a Massive Protostar—Detection of TiO in Orion Source I}},
author = {Ziwei E. Zhang and Nami Sakai and Marcelino Agúndez and Linda Podio and Claudio Codella and Tomoya Hirota and Adam Ginsburg and Brett McGuire and Nadia M. Murillo and Yuki Okoda and Yoko Oya and Giovanni Sabatini and Aki Takigawa and Kei E. I. Tanaka and Yichen Zhang and Qiuyi Luo and Yu Cheng and Izaskun Jiménez-Serra and Shogo Tachibana},
journal = {The Astrophysical Journal Letters},
year = {2026},
month = oct,
doi = {10.3847/2041-8213/aeacbe},
url = {https://iopscience.iop.org/article/10.3847/2041-8213/aeacbe},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Dust-seeding Molecules in a Massive Protostar—Detection of TiO in Orion Source I
AU - Ziwei E. Zhang
AU - Nami Sakai
AU - Marcelino Agúndez
AU - Linda Podio
AU - Claudio Codella
AU - Tomoya Hirota
AU - Adam Ginsburg
AU - Brett McGuire
AU - Nadia M. Murillo
AU - Yuki Okoda
AU - Yoko Oya
AU - Giovanni Sabatini
AU - Aki Takigawa
AU - Kei E. I. Tanaka
AU - Yichen Zhang
AU - Qiuyi Luo
AU - Yu Cheng
AU - Izaskun Jiménez-Serra
AU - Shogo Tachibana
PY - 2026
DA - 2026/10/23
JO - The Astrophysical Journal Letters
DO - 10.3847/2041-8213/aeacbe
UR - https://iopscience.iop.org/article/10.3847/2041-8213/aeacbe
AB - 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.
SN - 2041-8205
SN - 2041-8213
ER -