Exploring Chemical Evolution in Solar-Type Protostars by ALMA

• Project/Area Number: 25400223
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Astronomy
• Research Institution: Institute of Physical and Chemical Research (2015); The University of Tokyo (2013-2014)
• Principal Investigator: Sakai Nami 国立研究開発法人理化学研究所, 坂井星・惑星形成研究室, 准主任研究員 (70533553)
• Co-Investigator(Kenkyū-buntansha): YAMAMOTO Satoshi 東京大学, 大学院理学系研究科, 教授 (80182624)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Project Status: Completed (Fiscal Year 2015)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2015: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2013: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
• Keywords: 電波天文学 / 星間分子 / 星形成 / 惑星起源

Outline of Final Research Achievements

By using the state-of the art telescope like ALMA, we explored chenmical evolution in star forming regions. It has so far been believed that interstellar matter is smoothly brought into a gas disk forming a planetary system as it is. In the observation of the young protostar L1527 in Taurus, We have identified the radius of the centrifugal barrier of the infalling gas for the first time, and have discovered a drastic chemical change there. Since the centrifugal barrier can be regarded as the outermost boundary of the protostellar disk, the results clearly demonstrate that the infalling gas and dust are chemically processed when they go into the disk. We have also found that the more evolved protostar, TMC-1A, shows similar chemical change. Furthermore, we started unbiased chemical survery toward one large molecular cloud complex (Perseus). This will allow us to know how protostellar source shows chemical variety.

Research Products

• [Int'l Joint Research] CNRS(France)
• [Journal Article] Spectral Line Survey Toward Quiescent Giant Molecular Clouds in the Large Magellanic Cloud (2016)
  • Author(s): Nishimura Y., Shimonishi, T., Watanabe, Y., Sakai, N., Aikawa, Y., Kawamura, A., Yamamoto, S.
  • Journal Title: The Astrophysical Journal Volume: 818 Issue: 2 Pages: 1-17
  • DOI: 10.3847/0004-637x/818/2/161
  • Peer Reviewed
• [Journal Article] Implication of Formation Mechanisms of HC5N in TMC-1 as Studied by 13C Isotopic Fractionation (2016)
  • Author(s): Taniguchi, Kotomi; Ozeki, Hiroyuki; Saito, Masao; Sakai, Nami; Nakamura, Fumitaka; Kameno, Seiji; Takano, Shuro; Yamamoto, Satoshi
  • Journal Title: The Astrophysical Journal Volume: 817 Issue: 2 Pages: 147-147
  • DOI: 10.3847/0004-637x/817/2/147
  • Peer Reviewed
• [Journal Article] Subarcsecond Analysis of the Infalling-Rotating Envelope around the Class I Protostar IRAS 04365+2535 (2016)
  • Author(s): Sakai, Nami, Oya, Yoko, López-Sepulcre, Ana, Watanabe, Yoshimasa, Sakai, Takeshi, Hirota, Tomoya, Aikawa, Yuri, Ceccarelli, Cecilia, Lefloch, Bertrand, Caux, Emmanuel, Vastel, Charlotte, Kahane, Claudine, Yamamoto, Satoshi
  • Journal Title: The Astrophysical Journal Letters Volume: 820 Issue: 2 Pages: L34-L34
  • DOI: 10.3847/2041-8205/820/2/l34
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The role of SiO as a tracer of past star-formation events: The case of the high-mass protocluster NGC 2264-C (2016)
  • Author(s): Ana Lopez-Sepulcre, Yoshimasa Watanabe, Nami Sakai, Ryuta Furuya, Osamu Saruwatari, and Satoshi Yamamoto
  • Journal Title: The Astrophysical Journal Volume: in press
  • Peer Reviewed
• [Journal Article] Metanol in the Starless Core, Taurus Molecular Cloud-1 (2015)
  • Author(s): Soma, T., Sakai, N., Watanabe, Y., and Yamamoto, S.
  • Journal Title: Astrophysical Journal Volume: 802 Issue: 2 Pages: 9-9
  • DOI: 10.1088/0004-637x/802/2/74
  • Peer Reviewed
• [Journal Article] Kento Yoshida, Nami Sakai, Tomoya Tokudome, Ana Lopez-Sepulcre, Yoshimasa Watanabe, Shuro Takano, Bertrand Lefloch, Cecilia Ceccarelli, Rafael Bachiller, Emmanuel Caux, Charlotte Vastel, and Satoshi Yamamoto (2015)
  • Author(s): Kento Yoshida, Nami Sakai, Tomoya Tokudome, Ana Lopez-Sepulcre, Yoshimasa Watanabe, Shuro Takano, Bertrand Lefloch, Cecilia Ceccarelli, Rafael Bachiller, Emmanuel Caux, Charlotte Vastel, and Satoshi Yamamoto
  • Journal Title: The Astrophysical Journal Volume: 807 Issue: 1 Pages: 66-66
  • DOI: 10.1088/0004-637x/807/1/66
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Probing the effects of external irradiation on low-mass protostars through unbiased line survey (2015)
  • Author(s): Lindberg, J. E., Jorgensen, J. K., Watanabe, Y., Bisschop, S. E., Sakai, N., and Yamamoto, S
  • Journal Title: Astronomy and Astrophysics Volume: 584 Pages: 28-28
  • DOI: 10.1051/0004-6361/201526222
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] GEOMETRIC AND KINEMATIC STRUCTURE OF THE OUTFLOW/ENVELOPE SYSTEM OF L1527 REVEALED BY SUBARCSECOND-RESOLUTION OBSERVATION OF CS (2015)
  • Author(s): Oya, Y., Sakai, N., Lefloch, B., Lopez-Sepulcre, A., Watanabe, Y., Ceccarelli, C., and Yamamoto, S.
  • Journal Title: Astrophysical Journal Volume: 812 Issue: 1 Pages: 59-70
  • DOI: 10.1088/0004-637x/812/1/59
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] OH 18 cm Transition as a Thermometer for Molecular Clouds (2015)
  • Author(s): Yuji Ebisawa, Hiroshi Inokuma, Nami Sakai, Karl M. Menten, Hiroyuki Maezawa, and Satoshi Yamamoto
  • Journal Title: The Astrophysical Journal Volume: 815 Issue: 1 Pages: 13-13
  • DOI: 10.1088/0004-637x/815/1/13
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] A Chemical View of Protostellar-disk Formation in L1527 (2014)
  • Author(s): Sakai, N., Oya, Y., Sakai, T., Watanabe, Y., Hirota, T., Ceccarelli, C., Kahane, C., Lopez-Sepulcre, A., Lefloch, B., Vastel, C., Bottinelli, S., Caux, E., Coutens, A., Aikawa, Y., Takakuwa, S., Ohashi, N., Yen, H-W, Yamamoto, S.
  • Journal Title: The Astrophysical Journal Lettres Volume: 791 Issue: 2 Pages: 38-38
  • DOI: 10.1088/2041-8205/791/2/l38
  • Peer Reviewed
• [Journal Article] A Substellar-Mass Protostar and Its Outflow of IRAS 15398-3359 Revealed by Subarcsecond-Resolution Observations of H2CO and C2H (2014)
  • Author(s): Oya, Y
  • Journal Title: The Astrophysical Journal Volume: 795 Issue: 2 Pages: 9-9
  • DOI: 10.1088/0004-637x/795/2/152
  • Peer Reviewed
• [Journal Article] Change in the Chemical Composition of Infalling Gas Forming a Disk around a Protostar (2014)
  • Author(s): N. Sakai, T. Sakai, T. Hirota, Y. Watanabe, C. Ceccarelli, C. Kahane, S. Bottinelli, E. Caux, K, Demyk, C. Vastel, A. Coutens, V. Taquet, N. Ohashi, S. Takakuwa, H.-W. Yen, Y. Aikawa, and S.Yamamoto
  • Journal Title: Nature Volume: 507 Issue: 7490 Pages: 78-80
  • DOI: 10.1038/nature13000
  • Peer Reviewed
• [Journal Article] Anomalous ^<13>C Isotope Abundances in C_3S and C_4H Observed toward the Cold Interstellar Cloud, Taurus Molecular Cloud-1 (2013)
  • Author(s): N. Sakai, S. Takano, T. Sakai, S. Shiba, Y. Sumiyoshi, Y. Endo, and S.Yamamoto, S
  • Journal Title: J. Phys. Chem. A Volume: 117 Issue: 39 Pages: 9831-9839
  • DOI: 10.1021/jp3127913
  • Peer Reviewed
• [Journal Article] Warm Carbon-Chain Chemistry (2013)
  • Author(s): N. Sakai
  • Journal Title: Chemical Reviews Volume: 113 Pages: 8981-9015
  • Peer Reviewed
• [Presentation] Centrifugal Barrier of Infalling-Rotating Envelope around the Class I Protostar IRAS 04365+2535 (2016)
  • Author(s): 坂井南美
  • Organizer: 日本天文学会
  • Place of Presentation: 首都大学(東京都)
  • Year and Date: 2016-03-14
• [Presentation] Disks and Outflow System in Low-Mass Protostellar Sources (2015)
  • Author(s): Nami Sakai and Yoko Oya
  • Organizer: Protoplanetary Disk Dynamics and Planet Formation
  • Place of Presentation: JAMSTEC, Yokohama, Japan
  • Year and Date: 2015-09-29
  • Int'l Joint Research / Invited
• [Presentation] ペルセウス座分子雲の原始星天体に対する重水素濃縮度のサーベイ観測 (2015)
  • Author(s): 今井 宗明
  • Organizer: 星形成の諸階層 - 銀河から惑星まで
  • Place of Presentation: フォレスト箱根（神奈川県）
  • Year and Date: 2015-09-14
• [Presentation] Unbiased Chemical Survey of Protostellar Sources in Perseus (2015)
  • Author(s): 坂井南美
  • Organizer: 日本天文学会
  • Place of Presentation: 甲南大学(兵庫県）
  • Year and Date: 2015-09-09
• [Presentation] Class 0原始星IRAS 16293-2422におけるエンベロープの速度構造解析 (2015)
  • Author(s): 大屋瑶子
  • Organizer: 日本天文学会
  • Place of Presentation: 甲南大学(兵庫県）
  • Year and Date: 2015-09-09
• [Presentation] Observational Studies on Molecular Evolution in Star and Planet Forming Regions (2015)
  • Author(s): Nami Sakai
  • Organizer: 6th International Workshop on Electrostatic Storage Devices
  • Place of Presentation: Tokyo Metropolitan University, Tokyo, Japan
  • Year and Date: 2015-06-08
  • Int'l Joint Research / Invited
• [Presentation] Protostellar Disk Formation Traced by Chemistry (2015)
  • Author(s): Nami Sakai
  • Organizer: 3rd DTA Symposium, The Origins of Planetary Systems: from the Current View to New Horizons
  • Place of Presentation: NAOJ, Tokyo, Japan
  • Year and Date: 2015-06-01
  • Int'l Joint Research / Invited
• [Presentation] ALMAによるおうし座Class 0 原始星L1527の観測 (2015)
  • Author(s): 大屋瑶子
  • Organizer: 日本天文学会2015年春季年会
  • Place of Presentation: 大阪大学・豊中キャンパス（大阪府）
  • Year and Date: 2015-03-19
• [Presentation] A Chemical View of Protostellar-Disk Formation in L1527 (2014)
  • Author(s): Sakai, N
  • Organizer: 日本天文学会2014年秋季年会
  • Place of Presentation: 山形大学（山形県）
  • Year and Date: 2014-09-12
• [Presentation] 若い原始星に付随するエンベロープおよびアウトフローのモデル解析 (2014)
  • Author(s): 大屋瑶子
  • Organizer: 日本天文学会2014年秋季年会
  • Place of Presentation: 山形大学（山形県）
  • Year and Date: 2014-09-12
• [Presentation] New carbon-chain chemistry found in solar-type star-forming regions (2014)
  • Author(s): N. Sakai
  • Organizer: 247th American Chemical Society National Meeting 2014
  • Place of Presentation: Dallas Convention Center (USA)
  • Invited
• [Presentation] A Drastic Chemical Change in Protostellar-Disk Formation: IRAS 04368+2557 in L1527 (2014)
  • Author(s): N. Sakai
  • Organizer: 日本天文学会2014年春季年会
  • Place of Presentation: 国際基督教大学
• [Presentation] Astrochemistry in Star/Planet Forming Regions (2013)
  • Author(s): N. Sakai
  • Organizer: ALMA Developement Workshop
  • Place of Presentation: 国立天文台・三鷹
  • Invited
• [Presentation] A Drastic Chemical Change in Protostellar Disk Formation (2013)
  • Author(s): 坂井 南美
  • Organizer: 原始惑星系円盤研究会
  • Place of Presentation: 国立天文台・三鷹
  • Invited