Nanase Harada, Yasuhiro Hasegawa, Yuri Aikawa, Hiroyuki Hirashita, Hauyu Baobab Liu, Naomi Hirano,
Abstract Recent observations suggested that the growth of dust grains may have already occurred in class 0/I young stellar objects (YSOs). Since chemical reactions on dust grain surfaces are important in determining molecular abundances, the dust size growth may affect chemical compositions in YSOs significantly. In this work, we aim to determine how grain growth affects chemical abundances. We use a time-dependent gas-grain chemical model for a star-forming core to calculate the gas-phase and grain- ...
Tópico(s): Astro and Planetary Science
2017 - IOP Publishing | The Astrophysical Journal
Yoshimasa Watanabe, Y. Nishimura, Nanase Harada, Nami Sakai, Takashi Shimonishi, Yuri Aikawa, Akiko Kawamura, Satoshi Yamamoto,
We have conducted a mapping spectral line survey toward the Galactic giant molecular cloud W51 in the 3 mm band with the Mopra 22 m telescope in order to study an averaged chemical composition of the gas extended over a molecular cloud scale in our Galaxy. We have observed the area of $25' \times 30'$, which corresponds to 39 pc $\times$ 47 pc. The frequency ranges of the observation are 85.1 - 101.1 GHz and 107.0 - 114.9 GHz. In the spectrum spatially averaged over the observed area, spectral lines of ...
Tópico(s): Stellar, planetary, and galactic studies
2017 - IOP Publishing | The Astrophysical Journal
Y. Nishimura, Yoshimasa Watanabe, Nanase Harada, Takashi Shimonishi, Nami Sakai, Yuri Aikawa, Akiko Kawamura, Satoshi Yamamoto,
In order to study a molecular-cloud-scale chemical composition, we have conducted a mapping spectral line survey toward the Galactic molecular cloud W3(OH), which is one of the most active star forming regions in the Perseus arm, with the NRO 45 m telescope. We have observed the area of 16' $\times$ 16', which corresponds to 9.0 pc $\times$ 9.0 pc. The observed frequency ranges are 87--91, 96--103, and 108--112 GHz. We have prepared the spectrum averaged over the observed area, in which 8 molecular ...
Tópico(s): Advanced Combustion Engine Technologies
2017 - IOP Publishing | The Astrophysical Journal
Nanase Harada, Y. Nishimura, Yoshimasa Watanabe, Satoshi Yamamoto, Yuri Aikawa, Nami Sakai, Takashi Shimonishi,
Abstract It is important to understand the origin of molecular line intensities and chemical composition at the molecular-cloud scale in Galactic sources because it serves as a benchmark to compare with the chemical compositions of extragalactic sources. Recent observations of 3-mm spectra averaged over a 10 pc scale show similar spectral patterns among sources for molecular lines HCN, HCO + , CCH, HNC, HNCO, c-C 3 H 2 , CS, SO, N 2 H + , and CN. To constrain the average physical properties emitting such ...
Tópico(s): Molecular Spectroscopy and Structure
2019 - IOP Publishing | The Astrophysical Journal