MULTI-WAVELENGTH OBSERVATIONS OF COMET C/2011 L4 (PAN-STARRS)

作者：Yang Bin^*; Keane Jacqueline; Meech Karen; Owen Tobias; Wainscoat Richard

来源：Astrophysical Journal Letters, 2014, 784(2): L23.

DOI：10.1088/2041-8205/784/2/L23

• comets: individual (C/2011 L4)
• infrared: planetary systems
• Oort Cloud

The dynamically new comet C/2011 L4 (Pan-STARRS) is one of the brightest comets observed since the great comet C/1995 O1 (Hale-Bopp). Here, we present our multi-wavelength observations of C/2011 L4 during its in-bound passage to the inner solar system. A strong absorption band of water ice at 2.0 mu m was detected in the near-infrared spectra, obtained with the 8 m Gemini-North and 3 m Infrared Telescope Facility Telescopes. The companion 1.5 mu m band of water ice, however, was not observed. Spectral modeling shows that the absence of the 1.5 mu m feature can be explained by the presence of sub-micron-sized fine ice grains. No gas lines (i.e., CN, HCN, or CO) were observed pre-perihelion in either the optical or the submillimeter. We derived 3 sigma upper limits for the CN and CO production rates. The comet exhibited a very strong continuum in the optical and its slope seemed to become redder as the comet approached the Sun. Our observations suggest that C/2011 L4 is an unusually dust-rich comet with a dust-to-gas mass ratio >4.

• 出版日期2014-4-1