Four young stars with nearly edge-on disks observed by the Hubble Space Telescope. All are shown at the same linear scale, with each box being 1200 astronomical units square (111 billion miles, or about 20 times the diameter of Neptune's orbit). The different sizes and structures of the disks provide clues to their masses and evolutionary states.
Top row: NICMOS images of IRAS 04302+2247 and Orion 114-426.
Bottom row: WFPC2 images of HH 30 and HK Tau/c.
Credit (top left): Deborah Padgett, IPAC/Caltech
Credit (top right): Mark McCaughrean, Astrophysikalisches Institut Potsdam
Credit (bottom left): Chris Burrows, STScI
Credit (bottom right): Karl Sapelfeldt, JPL/Caltech