TENTATIVE DETECTION OF DEUTERATED METHANE TOWARD THE LOW-MASS PROTOSTAR IRAS 04368+2557 IN L1527
TENTATIVE DETECTION OF DEUTERATED METHANE TOWARD THE LOW-MASS PROTOSTAR IRAS 04368+2557 IN L1527
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DOI：
10.1088/2041-8205/758/1/l4
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发表时间：
2012-09
期刊：
影响因子：
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通讯作者：
N. Sakai;Y. Shirley;T. Sakai;T. Hirota;Yoshimasa Watanabe;S. Yamamoto
中科院分区：
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作者：
N. Sakai;Y. Shirley;T. Sakai;T. Hirota;Yoshimasa Watanabe;S. Yamamoto
用海因里希·赫兹亚毫米波望远镜对L1527中低质量0级原恒星IRAS 04368+2557的氚甲烷CH3d的毫米波转动跃迁线(Jk=10-00)进行了初步探测。如果得到证实，这是首次在星际云中检测到CH3D。当旋转温度为25K时，CH3d的柱密度和相对丰度分别为(9.1±3.4)×10 15 cm−2和(3.0±1.1)×10−7。采用L15 2 7中报道的分子D/H比为2%~7%，估算出气态CH4的柱密度和相对丰度分别为(1.3~4.6)×10 17 cm−2和(4.3~15.2)×10−6。甲烷的分数丰度高于或相当于红外观测在高质量恒星形成核心中发现的丰度。它足够高，足以在原恒星附近的温区触发各种碳链分子的有效生产，这支持了温暖碳链化学的情景。
The millimeter-wave rotational transition line (JK = 10–00) of deuterated methane CH3D has tentatively been detected toward the low-mass Class 0 protostar IRAS 04368+2557 in L1527 with the Heinrich Hertz Submillimeter Telescope. This is the first detection of CH3D in interstellar clouds, if confirmed. The column density and fractional abundance of CH3D are determined to be (9.1 ± 3.4) × 1015 cm−2 and (3.0 ± 1.1) × 10−7, respectively, where we assume the rotational temperature of 25 K. The column density and fractional abundance of the gaseous CH4 are estimated to be (1.3–4.6) × 1017 cm−2 and (4.3–15.2) × 10−6, respectively, by adopting the molecular D/H ratios of 2%–7% reported for various molecules in L1527. The fractional abundance of CH4 is higher than or comparable to that found in high-mass star-forming cores by infrared observations. It is sufficiently high to trigger the efficient production of various carbon-chain molecules in a lukewarm region near the protostar, which supports the scenario of warm carbon-chain chemistry.