[연구필요성]
By understanding how organic molecules, which are the origin of life, are created and evolved to be included in planets in the star formation process similar to our solar system, we explore the origins of the solar system and the emergence of life on Earth.
[연구성과/기대효과]
Organic molecules such as H2CO, CH3OH, HCOOH and C2H5OH have been detected in the frozen state around the embryonic star. Unlike previously observed simple ice molecules such as water (H2O), carbon monoxide (CO), and carbon dioxide (CO2), organic molecular ice is very small in quantity, making it difficult to detect with previous observation equipment. Using the James Webb Space Telescope’s high-performance spectrometer, which has excellent light-gathering power, it was possible to observe the faint absorption lines of these organic molecules in the frozen state. If the spectrum of gaseous organic molecules observed by the giant interferometric radio telescope ALMA and the spectrum of organic molecules in the icy state observed by the James Webb Space Telescope are combined and studied comprehensively, the chemical reaction of organic molecules occurring on the surface of space dust It is predicted that we will be able to make breakthrough advances in the study of evolutionary processes.
[본문]
A JWST Cycle 1 international joint project team of 14 astronomers from Japan, Korea, the United States and the Netherlands has succeeded in detecting the ice spectrum of complex organic molecules around a fetal star for the first time.done. The project is led by Dr. Yao-Lun Yang, a researcher at RIKEN in Japan. In Korea, Professor Jeongeun Lee of the Department of Physics and Astronomy of Seoul National University, research student Cheolhwan Kim, and postdoctoral researcher of the Research Institute of Astronomy and Space Sciences of Korea, Dr. Jaeyoung Kim attended .He’s doing
The research team is using the Mid-Infrared Instrument (MIRI) mounted on the James Webb Space Telescope to probe molecular ice in four very young embryos, one of which, IRAS15398-3359, passed It was observed as the first exploration target at May . IRAS15398-3359 is a young embryonic star at the center of a dark molecular cloud called Lupus I, about 500 light-years from Earth (Figure 1).
Called CORONIS (COMs ORigin Investigated by the Next-generation Observatory in Space), the project’s main mission is to investigate how many organic molecules and what composition there are in the icy material around the embryonic star. What we ultimately want to know through this investigation is how organic molecules, which are the origin of life, are created and evolved to be included in planets in the process of forming stars similar to our solar system, i.e. how we got there to exist here. Humanity has now reached a critical point in getting answers to these fundamental questions. Using the JWST, the star-forming region similar to the early solar system can be observed at a previously unimaginable level of resolution and sensitivity, and probes such as Hayabusa 2 can directly sample samples containing materials from the formation of the early solar system. can be collected and analyzed.
Since scientists believe that organic molecules such as methanol and ethanol are the origin of life on Earth, they have paid close attention to where and by what chemical process these organic molecules are produced. About 20 years ago, organic molecules began to be discovered where stars form and in comets, which are celestial objects of the solar system. These organic molecules are thought to be produced in an ice state on the surface of cosmic dust, but so far all organic molecules found outside the solar system have been observed in a gaseous state. That’s because the observing equipment wasn’t good enough to detect icy organic molecules where stars form.
The molecules in the ice state absorb the light of celestial bodies that emit infrared rays and use it as vibrational energy. By observing the resulting absorption spectrum, it is possible to study the type and quantity of molecules in the ice state. In the past, the absorption spectra of ice molecules such as H2O, CO, CO2 and CH4, which are relatively abundant, have been observed by the Spitzer Infrared Space Telescope and the AKARI Infrared Space Telescope.
However, organic molecular ice is very small, so a large telescope with good light-gathering power and an excellent spectrograph are essential to detect it. This discovery was made possible thanks to JWST, the first observation system in human history that satisfies these conditions. The JWST has 100 times the sensitivity and 10 times better resolution than previous infrared space telescopes, allowing it to decompose and observe gaseous organic molecules in the immediate vicinity of the observed fetal star, thus enabling chemical research to take place in the ice is making remarkable progress.
With this observation, the CORINOS project very clearly detected CO2, H2O and CH4, which are simple ice molecules, and H2CO, CH3OH and HCOOH, which are organic molecules, in the mid-infrared spectrum in the range of 5 to 28 microns ( Figure 2). Furthermore, the emission spectra of the neutral molecules H2, CO and H2O and the emission spectra of the ionic atoms Ne+ and Fe+ were also detected. These interactions were also well captured in images obtained with a mid-infrared camera (Fig. 3).
Observations of the project’s remaining three embryonic stars, led by Dr. Yao-Lun Yang, will take place next spring. At the same time, COMPASS (Complex Organic Molecules in Protostars with ALMA Spectral Surveys), an ALMA Cycle 9 Large Program co-lead by Prof. Jung-Eun Lee with European and American astronomers, identified 11 fetuses, including IRAS15398-3359 observed with JWST. A survey of the star’s gaseous organic molecules will be conducted in the first half of 2023. The combination of the composition and content of the frozen organic molecules observed with JWST and the gaseous organic molecules observed with ALMA will be the first attempt to understand how organic molecules form form and evolve during star formation. The Korean team, led by Professor Jeongeun Lee, is expected to make an important contribution to the interpretation of observational results by performing theoretical chemical model calculations and analysis of observational data in both projects.
The results were published in Astrophysical Journal Letters on December 12, 2022.
