We have obtained 11.7 and 17.9 μm images at the Keck I telescope of the circumstellar dust emission from L_2 Pup, which is one of the nearest (D = 61 pc) mass-losing, pulsating red giants that has a substantial infrared excess. We propose that the star is losing mass at a rate of ～3 x 10~(-7) soalr mass yr~(-1). Given its relatively low luminosity (～1500 soalr luminosity), relatively high effective temperature (near 3400 K), relatively short period (～140 days), and inferred gas outflow speed of 3.5 km s~(-1), standard models for dust-driven mass loss do not apply. Instead, the wind may be driven by the stellar pulsatipns, with radiation pressure on dust being relatively unimportant, as described in some recent calculations: L_2 Pup may serve as the prototype of this phase of stellar evolution, in which a star could lose ～ 15% of its initial main-sequence mass.
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机译：我们在Keck I望远镜上获得了来自L_2 Pup的星尘尘埃发射的11.7和17.9μm图像，L_2 Pup是最接近的（D = 61 pc）质量损失，脉动的红色巨星之一，其红外光明显过量。我们建议恒星以〜3 x 10〜（-7）的质量yr〜（-1）的速度失去质量。由于其相对较低的光度（约1500的碱性光度），相对较高的有效温度（约3400 K），相对较短的时间（约140天）以及推断的气体流出速度为3.5 km s〜（-1），因此是粉尘的标准模型驱动的质量损失不适用。取而代之的是，风可能是由恒星的脉动驱动的，尘埃上的辐射压力相对来说并不重要，如最近的一些计算中所述：L_2 Pup可以作为恒星演化这一阶段的原型，其中恒星可能损失〜15初始主序列质量的百分比。
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