Physical properties and chemical composition of the cores in the California molecular cloud
| العنوان: | Physical properties and chemical composition of the cores in the California molecular cloud |
|---|---|
| المؤلفون: | Jun-Jie Wang, A. Vasyunin, Zhong-Zu Wu, Tie Liu, Jin-Long Xu, Ke Wang, Dalei Li, Jinghua Yuan, D. A. Semenov, Di Li, Yang Gao, Xiao-Lan Liu, Chuan-Peng Zhang, Sami Dib, Sheng-Yuan Liu, Guoyin Zhang |
| المصدر: | Astronomy and Astrophysics |
| سنة النشر: | 2018 |
| مصطلحات موضوعية: | Astrochemistry, EFFICIENCY, 010504 meteorology & atmospheric sciences, Stellar mass, Extinction (astronomy), FOS: Physical sciences, DUST, CHEMICAL EVOLUTION, Astrophysics, 01 natural sciences, MASS TRANSFORMATION, FORMATION [STARS], 0103 physical sciences, PHYSICAL PROPERTIES, ABUNDANCES [ISM], PHYSICAL CONDITIONS, LIGHT EXTINCTION, 010303 astronomy & astrophysics, Chemical composition, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Line (formation), Physics, ASTROCHEMISTRY, CHEMICAL COMPOSITIONS, Star formation, Molecular cloud, CLOUDS, Astronomy and Astrophysics, GIANT STARS, Astrophysics - Astrophysics of Galaxies, Stars, EXTINCTION, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, ABUNDANCE [ISM], MOLECULES [ISM], Astrophysics of Galaxies (astro-ph.GA), TELESCOPES, FUNCTIONS |
| الوصف: | We aim to reveal the physical properties and chemical composition of the cores in the California molecular cloud (CMC), so as to better understand the initial conditions of star formation. We made a high-resolution column density map (18.2") with Herschel data, and extracted a complete sample of the cores in the CMC with the \textsl{fellwalker} algorithm. We performed new single-pointing observations of molecular lines near 90 GHz with the IRAM 30m telescope along the main filament of the CMC. In addition, we also performed a numerical modeling of chemical evolution for the cores under the physical conditions. We extracted 300 cores, of which 33 are protostellar and 267 are starless cores. About 51\% (137 of 267) of the starless cores are prestellar cores. Three cores have the potential to evolve into high-mass stars. The prestellar core mass function (CMF) can be well fit by a log-normal form. The high-mass end of the prestellar CMF shows a power-law form with an index $\alpha=-0.9\pm 0.1$ that is shallower than that of the Galactic field stellar mass function. Combining the mass transformation efficiency ($\varepsilon$) from the prestellar core to the star of $15\pm 1\%$ and the core formation efficiency (CFE) of 5.5\%, we suggest an overall star formation efficiency of about 1\% in the CMC. In the single-pointing observations with the IRAM 30m telescope, we find that 6 cores show blue-skewed profile, while 4 cores show red-skewed profile. [$\rm {HCO}^{+}$]/[HNC] and [$\rm {HCO}^{+}$]/$\rm [N_{2}H^{+}]$ in protostellar cores are higher than those in prestellar cores; this can be used as chemical clocks. The best-fit chemical age of the cores with line observations is $\sim 5\times 10^4$~years. Comment: Accepted by Astronomy & Astrophysics (A&A) |
| وصف الملف: | application/pdf |
| اللغة: | English |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7ae42aeade393c29245ab1794fe33db5Test http://arxiv.org/abs/1810.09522Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....7ae42aeade393c29245ab1794fe33db5 |
| قاعدة البيانات: | OpenAIRE |
| الوصف غير متاح. |