Z Andromedae: Quiescence and Activity

Molecular maps of neural activity and quiescence.

The rapid accumulation of inducible transcription factors (ITFs), such as c-Fos and Zif268, in activated neurons combined with histological methods that offer detection at the cellular level are key features that have led to their wide use in visualizing activated neurons. There are two major drawbacks of ITFs that limit their use in the CNS--cell-type expression specificity and stimulus-transc...

Discovery of a Magnetic White Dwarf in the Symbiotic Binary Z Andromedae

We report the first result from our survey of rapid variability in symbiotic binaries: the discovery of a persistent oscillation at P = 1682.6±0.6 s in the optical emission from the prototype symbiotic, Z Andromedae. The oscillation was detected on all 8 occasions on which the source was observed over a timespan of nearly a year, making it the first such persistent periodic pulse found in a sym...

A “combination Nova” Outburst in Z Andromedae: Nuclear Shell Burning Triggered by a Disk Instability

We describe observational evidence for a new kind of interacting-binary-star outburst that involves both an accretion instability and an increase in thermonuclear shell burning on the surface of an accreting white dwarf. We refer to this new type of eruption as a combination nova. In late 2000, the prototypical symbiotic star Z Andromedae brightened by roughly two magnitudes in the optical. We ...

The Upsilon Andromedae System: Models and Stability

Radial velocity observations of the F8 V star υ Andromedae taken at Lick and at Whipple Observatories have revealed evidence of three periodicities in the line-ofsight velocity of the star. These periodicities have been interpreted as evidence for at least three low mass companions (LMCs) revolving around υ Andromedae. The mass and orbital parameters inferred for these companions raise question...

The Dwarf Nova Pq Andromedae