High‐Resolution Near‐Infrared Images and Models of the Circumstellar Disk in HH 30

We present Hubble Space Telescope (HST) Near-Infrared Camera and Multi-objectSpectrometer (NICMOS) observations of the reflection nebulosity associated withthe T Tauri star HH 30. The images show the scattered light patterncharacteristic of a highly inclined, optically thick disk with a prominentdustlane whose width decreases with increasing wavelength. The reflectednebulosity exhibits a lateral asymmetry in the upper lobe on the opposite sideto that reported in previously published Wide Field Planetary Camera 2 (WFPC2)images. The radiation transfer model which most closely reproduces the data hasa flared accretion disk with dust grains larger than standard interstellarmedium grains by a factor of approximately 2.1. A single hotspot on the stellarsurface provides the necessary asymmetry to fit the images and is consistentwith previous modeling of the light curve and images. Photometric analysisresults in an estimated extinction of Av>~80; however, since the photometrymeasures only scattered light rather than direct stellar flux, this a lowerlimit. The radiative transfer models require an extinction of Av = 7,900.Comment: Accepted for publication in Ap.