Web Telescope Finds 'Origin of Life' in Fetal Star

International Collaborative Research Team Including Seoul National University Confirms Complex Organic Molecules

Ice molecule spectrum observed by the James Webb Space Telescope in a protostar forming within an interstellar cloud. Absorption lines of various organic molecules were detected. The blue circle in the center of the image indicates the location where the protostar IRAS15398-3359 is embedded in dense material. Image courtesy of Seoul National University.

[Asia Economy Reporter Kim Bong-su] An international joint research team, including domestic researchers from Seoul National University and the Korea Astronomy and Space Science Institute, has discovered organic molecules presumed to be the origin of life in protostars using observational data from the James Webb Space Telescope (JWST).

According to Seoul National University on the 13th, the international joint research team, including Professor Lee Jeong-eun from the Department of Physics and Astronomy at Seoul National University and Dr. Kim Jae-young from the Korea Astronomy and Space Science Institute, achieved this result through the CORINOS project using the Mid-Infrared Instrument (MIRI) installed on JWST. The project aims to investigate how much and what composition of organic molecules exist in the ice-state materials around protostars. The research goal is to explore how organic molecules, which are the origin of life, are formed and evolve during the formation process of stars similar to our solar system and how they become incorporated into planets?in other words, how we came to exist here.

The research team is conducting ice-state molecular surveys on four very young protostars. One of them, 'IRAS15398-3359,' was observed as the first target in May. It is a protostar just beginning to form at the center of a dark molecular cloud called 'Lupus I,' about 500 light-years away from Earth. As a result, the team successfully detected complex organic molecules H2CO, CH3OH, HCOOH, and C2H5OH in the ice state around the protostar for the first time. Unlike previously observed simple ice molecules such as water (H2O), carbon monoxide (CO), and carbon dioxide (CO2), the ice-state organic molecules are present in very small amounts, making detection difficult with previous observational equipment. Using JWST’s high-performance spectrometer with excellent light-gathering power, the team was able to observe the faint absorption lines of these organic molecules in the ice state.

The research team stated, "If we combine and comprehensively study the spectra of gas-phase organic molecules observed by the Atacama Large Millimeter/submillimeter Array (ALMA) and the spectra of ice-phase organic molecules observed by JWST, we expect to make groundbreaking progress in understanding the chemical reactions and evolutionary processes of organic molecules occurring on cosmic dust surfaces." They added, "Humanity has now reached a very important point in answering this ultimate question. Using JWST, we can observe star-forming regions similar to the early solar system with unprecedented resolution and sensitivity, and with probes like Hayabusa 2, we can directly collect and analyze samples containing materials from the early solar system."

Scientists believe that organic molecules such as methanol and ethanol are the origin of life on Earth. There has been great interest in where and through what chemical processes these organic molecules are formed. For over 20 years, organic molecules have been found in star-forming regions and in solar system bodies such as comets. These organic molecules are thought to be formed in ice states on the surfaces of cosmic dust. Until now, organic molecules found outside the solar system have all been observed in the gas phase because observational equipment was not sufficiently advanced to detect ice-phase organic molecules in star-forming regions.

Ice-state molecules absorb the light emitted by celestial bodies that emit infrared radiation and use it as vibrational energy. By observing the resulting absorption spectra, researchers can study the types and quantities of molecules in the ice state. In the past, relatively abundant ice molecules such as H2O, CO, CO2, and CH4 have been observed through absorption spectra by the Spitzer Infrared Space Telescope and the AKARI Infrared Space Telescope.

However, because organic molecule ices are present in very small amounts, detecting them requires large telescopes with excellent light-gathering power and highly capable spectrometers. Thanks to JWST, the first observational system in human history to meet these conditions, this discovery was possible. JWST has 100 times higher sensitivity and nearly 10 times better resolution than previous infrared space telescopes. It can observe regions adjacent to protostars where gas-phase organic molecules have been detected, enabling revolutionary progress in chemical research occurring in the ice state.

The CORINOS project, through this observation, clearly detected simple ice molecules CO2, H2O, CH4, and organic molecules H2CO, CH3OH, and HCOOH in the mid-infrared spectrum range of 5 to 28 microns. Although weak, C2H5OH and CH3CHO were also clearly detected. Additionally, emission spectra of neutral molecules H2, CO, H2O, and ionized atoms Ne+ and Fe+ were detected, indicating strong interactions between materials ejected by the protostar and the surrounding interstellar matter. These interactions were also well captured in images obtained by the mid-infrared camera.

The research team plans to conduct observations of the remaining three protostars next spring. At the same time, Professor Lee Jeong-eun is leading another research program jointly composed of European and American astronomers called the 'ALMA Cycle 9 Large Program' COMPASS, which will conduct a gas-phase organic molecule survey of 11 protostars, including IRAS15398-3359 observed by JWST, in the first half of 2023.

Seoul National University stated, "The combination of ice-phase organic molecules observed by JWST and gas-phase organic molecules observed by ALMA will be the first attempt to understand how organic molecules are formed and how they evolve during the star formation process." They added, "The Korean team led by Professor Lee Jeong-eun is expected to make significant contributions to interpreting the observational results by analyzing observational data and performing theoretical chemical model calculations in both projects."

The research results were published in the June 12 issue of The Astrophysical Journal Letters.

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