background and importance: disk sequestration can be defined as a herniated disk with perforation of the fibrous ring (or outermost annulus fibrosus) and posterior longitudinal ligament with migration of the disk fragment to the epidural space. even after the introduction of high-resolution magnetic resonance imaging (mri), it is still frequently misinterpreted as neoplastic masses. unfortunate...

Na i D lines in the spectrum of the young binary KH 15D have been analyzed in detail. We find an excess absorption component that may be attributed to foreground interstellar absorption, and to gas possibly associated with the solids in the circumbinary disk. The derived column density is log NNa i = 12.5 cm−2, centered on a radial velocity that is consistent with the systemic velocity. Subtrac...

We present a determination of themolecular gas mass in the AUMicroscopii circumstellar disk. Direct detection of a gas component to the AUMic disk has proven elusive, with upper limits derived from ultraviolet absorption line and submillimeter CO emission studies. Fluorescent emission lines of H2, pumped by theO vi k1032 resonance line through the CYX (1Y1) Q(3) k1031.87 8 transition, are detec...

Fragmentation process in a cylindrical magnetized cloud is studied with the nested grid method. The nested grid scheme use 15 levels of grids with diierent spatial resolution overlaid subsequently, which enables us to trace the evolution from the molecular cloud density 100cm ?3 to that of the protostellar disk 10 10 cm ?3 or more. Fluctuation with small amplitude grows by the gravitational ins...

We present a determination of the molecular gas mass in the AU Microscopii circumstellar disk. Direct detection of a gas component to the AU Mic disk has proven elusive, with upper limits derived from ultraviolet absorption line and submillimeter CO emission studies. Fluorescent emission lines of H2, pumped by the O VI λ1032 resonance line through the C–X (1 – 1) Q(3) λ1031.87 Å transition, are...

We analyze the resolved neutral hydrogen emission properties of a sample of eleven of the nearest spiral galaxies. Between 60 and 90% of the total H I line flux within the optical disk is due to a high brightness network (HBN) of emission features which are marginally resolved in their narrow dimension at about 150 pc and have a face-on covering factor of about 15%. Averaged line profiles of th...

Observations of submillimeter lines of CO, HCO, HCN and their isotopes from circumstellar disks around low mass pre-main sequence stars are presented. CO lines up to J=6→5, and HCO and HCN lines up to J=4→3, are detected from the disks around LkCa 15 and TW Hya. These lines originate from levels with higher excitation temperatures and critical densities than studied before. Combined with interf...

Using Spitzer Space Telescope photometric observations of the eclipsing, interacting binary WZ Sge, we have discovered that the accretion disk is far more complex than previously believed. Our 4.5 and 8 micron time series observations reveal that the well known gaseous accretion disk is surrounded by an asymmetric disk of dusty material with a radius approximately 15 times larger than the gaseo...