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A Survey of Near Infrared Emission in Visual Reflection Nebulae

K. Sellgren·M. W. Werner·L. J. Allamandola
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Abstract

We present a survey for extended 2.2 $μ$m emission in 20 new visual reflection nebulae, illuminated by stars with temperatures of 3,600 --- 33,000 K. We detect extended 2.2 $μ$m emission in 13 new nebulae, illuminated by stars with temperatures of 6,800 -- 33,000 K. For most of these 13 nebulae we have measured $J-K$, $H-K$, and $K-L'$, as well as obtaining surface brightness measurements at the wavelength of the 3.3 $μ$m emission feature. All of the reflection nebulae with extended near infrared emission in excess over scattered starlight have very similar near infrared colors and show the 3.3 $μ$m feature in emission with similar feature-to-continuum ratios. The 3.3 $μ$m feature-to-continuum ratio ranges from $\sim$3 to $\sim$9, both within individual nebulae and from nebula to nebula, which suggests that the 3.3 $μ$m feature and its underlying continuum arise from different materials, or from different ranges of sizes within a size distribution of particles. No dependence on the temperature of the illuminating star is seen in the near infrared colors or 3.3 $μ$m feature-to-continuum ratio, over a factor of two in stellar temperature. This is similar to our previous IRAS results, in which we found no dependence of the ratio of 12 $μ$m to 100 $μ$m surface brightnesses in reflection nebulae illuminated by stars with temperatures of 5,000--33,000 K.

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K. Sellgren, M. W. Werner, L. J. Allamandola. 1995-09-13. A Survey of Near Infrared Emission in Visual Reflection Nebulae. https://doi.org/10.1086/192262

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