Completion of a catalog of locations for near-future star birth in the Orion constellation---Discovery of Mysterious double-eye structure toward a baby star--
Abstract Places to form stars are called “molecular clouds,” where molecular gas is accumulated in space. Their densest parts are called “molecular cloud cores,” and stars form right there. It is believed that the center of these “cores” further shrink because of gravity, and eventually form baby stars called “protostars.” However, not all “cores” necessarily form stars, and also it was not easy to know from which “cores” star will form. An international research team lead by Gwanjeong Kim and Ken Tatematsu of the Nobeyama Radio Observatory, Japan, made use of deuterium, which is a special kind of hydrogen, and succeeded to know exact places for near-future star formation, by using a fact that the deuterium percentage reaches its maximum just at the time of star formation. First, they used the 45 m radio telescope of the Nobeyama Radio Observatory to measure the deuterium percentage in “cores” in the Orion constellation, and completed a catalog of places for near-future star formation. Next, they observed “cores” having high deuterium percentage with the Morita Array, which is East-Asian constructed part of the world most powerful radio telescope ALMA. As a result, we obtained evidence of the “increasing weight” motion at an exact place before star formation, and also discovered a mysterious double-eye structure near a baby star. These results give us an important clue to understand how stars start to form.
- Figure: Picture of the Orion constellation and radio maps obtained with the Nobeyama telescope and ALMA-Morita Array. The bottom right panel shows the mysterious double-eye structure. Mid row panels show the distribution of a hydrogen-containing molecule, and the bottom row panels show the close-up view obtained with the ALMA-Morita Array using a deuterium-containing molecule.