TY - JOUR
T1 - Reflected light from sand grains in the terrestrial zone of a protoplanetary disk
AU - Herbst, William
AU - Hamilton, Catrina M.
AU - LeDuc, Katherine
AU - Winn, Joshua N.
AU - Johns-Krull, Christopher M.
AU - Mundt, Reinhard
AU - Ibrahimov, Mansur
N1 - Funding Information:
Acknowledgements This material is based on work supported by the US National Aeronautics and Space Administration (NASA) through the Origins of Solar Systems programme. Some of the data presented here were obtained at the W. M. Keck Observatory from telescope time allocated to NASA through the agency’s scientific partnership with the California Institute of Technology and the University of California. The Observatory was made possible by the financial support of the W. M. Keck Foundation. We appreciate comments from E. Chiang, M. Gilmore, J. Greenwood and E. Jensen.
PY - 2008/3/13
Y1 - 2008/3/13
N2 - In the standard model of terrestrial planet formation, the first step in the process is for interstellar dust to coagulate within a protoplanetary disk surrounding a young star, forming large grains that settle towards the disk plane. Interstellar grains of typical size ∼0.1 μm are expected to grow to millimetre- (sand), centimetre- (pebble) or even metre-sized (boulder) objects rather quickly. Unfortunately, such evolved disks are hard to observe because the ratio of surface area to volume of their constituents is small. We readily detect dust around young objects known as 'classical' T Tauri stars, but there is little or no evidence of it in the slightly more evolved 'weak-line' systems. Here we report observations of a 3-Myr-old star, which show that grains have grown to about millimetre size or larger in the terrestrial zone (within ∼3 au) of this star. The fortuitous geometry of the KH 15D binary star system allows us to infer that, when both stars are occulted by the surrounding disk, it appears as a nearly edge-on ring illuminated by one of the central binary components. This work complements the study of terrestrial zones of younger disks that have been recently resolved by interferometry.
AB - In the standard model of terrestrial planet formation, the first step in the process is for interstellar dust to coagulate within a protoplanetary disk surrounding a young star, forming large grains that settle towards the disk plane. Interstellar grains of typical size ∼0.1 μm are expected to grow to millimetre- (sand), centimetre- (pebble) or even metre-sized (boulder) objects rather quickly. Unfortunately, such evolved disks are hard to observe because the ratio of surface area to volume of their constituents is small. We readily detect dust around young objects known as 'classical' T Tauri stars, but there is little or no evidence of it in the slightly more evolved 'weak-line' systems. Here we report observations of a 3-Myr-old star, which show that grains have grown to about millimetre size or larger in the terrestrial zone (within ∼3 au) of this star. The fortuitous geometry of the KH 15D binary star system allows us to infer that, when both stars are occulted by the surrounding disk, it appears as a nearly edge-on ring illuminated by one of the central binary components. This work complements the study of terrestrial zones of younger disks that have been recently resolved by interferometry.
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U2 - 10.1038/nature06671
DO - 10.1038/nature06671
M3 - Article
C2 - 18337817
AN - SCOPUS:40749121348
SN - 0028-0836
VL - 452
SP - 194
EP - 197
JO - Nature
JF - Nature
IS - 7184
ER -