首页> 外文期刊>The Astrophysical journal >CCS AND NH_3 EMISSION ASSOCIATED WITH LOW-MASS YOUNG STELLAR OBJECTS
【24h】

CCS AND NH_3 EMISSION ASSOCIATED WITH LOW-MASS YOUNG STELLAR OBJECTS

机译:低质量年轻恒星与CCS和NH_3排放相关

获取原文
获取原文并翻译 | 示例
获取外文期刊封面目录资料

摘要

In this work we present a sensitive and systematic single-dish survey of CCS emission (complemented with ammonia observations) at 1 cm, toward a sample of low- and intermediate-mass young star-forming regions known to harbor water maser emission, made with NASA's 70 m antenna at Robledo de Chavela, Spain. Out of the 40 star-forming regions surveyed in the CCS (2_1-1_0) line, only six low-mass sources show CCS emission: one transitional object between the prestellar and protostellar Class 0 phase (GF9-2), three Class 0 protostars (L1448-IRS3, L1448C, and B1-IRS), a Class I source (L1251A), and a young T Tauri star (NGC 2071 North). Since CCS is considered an "early-time" (approx< 10~5 yr) molecule, we explain these results by either proposing a revision of the classification of the age of NGC 2071 North and L1251 A, or suggesting the possibility that the particular physical conditions and processes of each source affect the destruction/production of the CCS. No statistically significant relationship was found between the presence of CCS and parameters of the molecular outflows and their driving sources. Nevertheless, we found a significant relationship between the detectability of CCS and the ammonia peak intensity (higher in regions with CCS), but not with its integrated intensity. This tendency may suggest that the narrower ammonia line widths in the less turbulent medium associated with younger cores may compensate for the differences in ammonia peak intensity, rendering differences in integrated intensity negligible. From the CCS detection rate we derive a lifetime of this molecule of approx=(0.7-3) x 10~4 yr in low-mass star-forming regions.
机译:在这项工作中,我们对1 cm处的CCS排放进行了敏感而系统的单碟测量(补充了氨气观测),以对已知具有水maser排放的中低质量年轻恒星形成区域的样本进行了研究, NASA在西班牙Robledo de Chavela的70 m天线。在CCS(2_1-1_0)线调查的40个恒星形成区域中,只有六个低质量源显示CCS发射:一个是星际和原星的0级星相(GF9-2)之间的过渡物体,三个是0级的原星(L1448-IRS3,L1448C和B1-IRS),I类辐射源(L1251A)和年轻的T Tauri星(NGC 2071北)。由于CCS被认为是“早期”(约<10到5年)分子,因此我们通过提议修订NGC 2071 North和L1251 A的年龄分类,或暗示这种可能性来解释这些结果。每个来源的物理条件和过程都会影响CCS的破坏/生产。在CCS的存在与分子流出参数及其驱动源之间没有发现统计学上的显着关系。然而,我们发现CCS的可检测性与氨峰强度(在CCS区域中更高)之间存在显着的关系,但与积分强度无关。这种趋势可能表明,与较年轻岩心相关的湍流较小的介质中较窄的氨线宽度可以补偿氨峰强度的差异,从而使积分强度的差异可忽略不计。根据CCS的检出率,我们得出该分子在低质量恒星形成区的寿命约为=(0.7-3)x 10〜4年。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号