Nations, H. L. | Engineering Papers

NASA NTRS1983

Spectroscopy of blue stellar objects

Spectra have been obtained for the brightest objects from a list of blue stellar objects found in a Palomar Schmidt field centered on Kapteyn Selected Area 28. Four of the objects presented here comprise a complete sample of objects with UV excess and magnitudes brighter than or equal to B = 16.3 mag. The object with the largest UV excess is a previously undiscovered quasar of redshift 0.25 and cataloged B magnitude of 15.6 mag. The object shows some evidence of variability. Spectroscopy for one bright object in a companion field centered on Selected Area 29 is also presented.

Mitchell, K. J.↗

NASA NTRS1981

A flare event in the peculiar giant FK Comae

Observations are presented of a very energetic flare event in the peculiar rapidly rotating star FK Comae. During this event on June 18th 1981 the usual asymmetrical double peaked H alpha emission feature with an equivalent width (EW) approx 3-4 A changed to a broad emission feature with EW approx 13 A. Sixteen spectra were obtained over 2 hours. Some changes in the emission profile are apparent on this time scale. The following night the enhanced emission persisted but at lower levels and it was substantially redshifted. This event is interpreted in terms of a model where material is injected into a disk co-rotating with the angular velocity of the stellar surface. A localized region of surface activity is conjectured to be the source of the event.

Ramsey, L. W.↗