Probing changes of dust properties along a chain of solar-type prestellar and protostellar cores in Taurus with NIKA
Probing changes of dust properties along a chain of solar-type prestellar and protostellar cores in Taurus with NIKA
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DOI：
10.1051/0004-6361/201731117
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发表时间：
2017-06
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通讯作者：
A. Bracco;P. Palmeirim;P. Andr'e;R. Adam;P. Ade;A. Bacmann;A. Beelen;A. Benoȋt;A. Bideaud;N. Billot;O. Bourrion;M. Calvo;A. Catalano;G. Coiffard;B. Comis;A. D’Addabbo;F. Désert;P. Didelon;S. Doyle;J. Goupy;V. Konyves;C. Kramer;G. Lagache;S. Leclercq;J. Mac'ias-P'erez;A. Maury;P. Mauskopf;P. Mauskopf;F. Mayet;A. Monfardini;F. Motte;F. Pajot;E. Pascale;N. Peretto;L. Perotto;G. Pisano;N. Ponthieu;V. Rev'eret;A. Rigby;A. Ritacco;L. Rodriguez;C. Romero;A. Roy;F. Ruppin;K. Schuster;A. Sievers;S. Triqueneaux;C. Tucker;R. Zylka
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作者：
A. Bracco;P. Palmeirim;P. Andr'e;R. Adam;P. Ade;A. Bacmann;A. Beelen;A. Benoȋt;A. Bideaud;N. Billot;O. Bourrion;M. Calvo;A. Catalano;G. Coiffard;B. Comis;A. D’Addabbo;F. Désert;P. Didelon;S. Doyle;J. Goupy;V. Konyves;C. Kramer;G. Lagache;S. Leclercq;J. Mac'ias-P'erez;A. Maury;P. Mauskopf;P. Mauskopf;F. Mayet;A. Monfardini;F. Motte;F. Pajot;E. Pascale;N. Peretto;L. Perotto;G. Pisano;N. Ponthieu;V. Rev'eret;A. Rigby;A. Ritacco;L. Rodriguez;C. Romero;A. Roy;F. Ruppin;K. Schuster;A. Sievers;S. Triqueneaux;C. Tucker;R. Zylka
星际介质（ISM）中尘埃特性的表征是恒星形成的关键。质量估计对于确定分子云中新恒星物体诞生的引力坍缩条件至关重要。然而，这些估计大多依赖于尘埃模型，这些模型需要从云到恒星前和原恒星核心的进一步观测约束。本文介绍了一项基于NIKA相机在IRAM-30m望远镜上获得的毫米连续体数据的尘埃发射率变化研究结果。在1.15 mm和2 mm处观测尘埃发射，使我们能够将尘埃发射率指数（$\beta$）限制在尘埃光谱能量分布（SED）的瑞利-牛仔裤尾部，远离其峰值发射，在那里其他参数（即尘埃温度）的贡献是重要的。以Gould带中的低质量恒星形成区金牛座分子云为研究对象，分析了B213灯丝中3个恒星前核、2个0/I类原恒星核和1个ii类天体的发射特性。通过两个NIKA通道图的比值，我们表明，在瑞利-琼斯近似中，尘埃发射率指数在不同的物体之间是不同的。对于一个恒星前核心和两个原恒星核心，我们使用赫歇尔数据进行了一个强有力的研究，以约束源的尘埃温度。利用Abel变换反演技术，得到了精确的径向$\beta$剖面。我们发现$\beta$在原恒星核心中有系统的空间变化，这在前恒星核心中没有观察到。在前一种情况下，$\beta$向中心减小，而在后一种情况下，它保持不变。此外，$\beta$似乎与尘埃温度不相关。我们讨论了这些结果在前恒星和原恒星核之间尘埃颗粒演化的意义。
The characterization of dust properties in the interstellar medium (ISM) is key for star formation. Mass estimates are crucial to determine gravitational collapse conditions for the birth of new stellar objects in molecular clouds. However, most of these estimates rely on dust models that need further observational constraints from clouds to prestellar and protostellar cores. We present results of a study of dust emissivity changes based on mm-continuum data obtained with the NIKA camera at the IRAM-30m telescope. Observing dust emission at 1.15 mm and 2 mm allows us to constrain the dust emissivity index ($\beta$) in the Rayleigh-Jeans tail of the dust spectral energy distribution (SED) far from its peak emission, where the contribution of other parameters (i.e. dust temperature) is important. Focusing on the Taurus molecular cloud, a low-mass star-forming regions in the Gould Belt, we analyze the emission properties of several distinct objects in the B213 filament: three prestellar cores, two Class-0/I protostellar cores and one Class-II object. By means of the ratio of the two NIKA channel-maps, we show that in the Rayleigh-Jeans approximation the dust emissivity index varies among the objects. For one prestellar and two protostellar cores, we produce a robust study using Herschel data to constrain the dust temperature of the sources. By using the Abel transform inversion technique we get accurate radial $\beta$ profiles. We find systematic spatial variations of $\beta$ in the protostellar cores that is not observed in the prestellar core. While in the former case $\beta$ decreases toward the center, in the latter it remains constant. Moreover, $\beta$ appears anticorrelated with the dust temperature. We discuss the implication of these results in terms of dust grain evolution between pre- and protostellar cores.