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Recalibration of the Wilson-Bappu Effect Using the Singly Ionized Magnesium K Line

Mena-Werth, Jose; Scoville, Frederick

A new calibration of the Wilson-Bappu effect is presented using data from a survey of the singly ionized magnesium (Mg ii) h and k lines (near 280 nm) taken from the archives of the International Ultraviolet Explorer satellite. Our sample consisted of 94 stars with absolute magnitudes derived from parallaxes reported from Hipparcos. We describe th…

A Search for an Emission-Line Region in the Hydrogen-deficient Carbon Star HD 182040

Clayton, Geoffrey C.; Ayres, T. R.; Brunner, Andrew R.

A long-exposure short-wavelength IUE spectrum of the hydrogen-deficient carbon (HdC) star HD 182040 does not show any detectable emission in the C II lambda1335 line. It is not certain whether this absence of emission is intrinsic or due to the large uncertainties in the distance, absolute luminosity, and reddening toward HD 182040. If intrinsic, …

Hubble Space Telescope/Faint Object Spectrograph Imaging of Wolf 424 AB: Is This Binary a Double Brown Dwarf System?

Benedict, G. F.; Franz, O. G.; Bruhweiler, F. C. +9 more

The low-mass binary system Wolf 424 AB (GJ 473 AB) was spatially resolved in an image obtained on 1996 April 16 with the imaging mode of the Hubble Space Telescope Faint Object Spectrograph. The separation was measured to be 0.42"+/-0.03" at a position angle of 353.2d+/-2.5d. The new measurement was combined with previously published orbital posit…

Duplicity in Hubble Space Telescope Guide Stars: Fine Guidance Sensor Serendipitous Survey Results

Schneider, Glenn; Hershey, John L.; Wenz, Michael T.

Data from the Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) interferometers, covering 22 months of guide-star acquisition operations, have been analyzed for evidence of stellar duplicity. The data comprise a survey of observed guide stars, all of which are taken from the HST Guide Star Catalog, ranging in magnitude from 9 to 14. The surv…

Is the Galactic Halo Planetary Nebula PN G243-37.1 an ``O VI Sequence'' Variable Object?

Feibelman, Walter A.

Archival IUE spectra of the Galactic halo planetary nebula PN G243-37.1 have been reprocessed by the NEWSIPS routine. The new results show a much richer emission-line spectrum than has previously been reported. Several C iii, C iv, O v, and possibly O vi features were detected. P Cygni line profiles could not be identified with certainty. The He i…

STIS Signal-to-Noise Capabilities in the Ultraviolet

Kaiser, Mary Elizabeth; Kimble, Randy A.; Gilliland, Ronald L. +3 more

The Space Telescope Imaging Spectrograph (STIS) was designed as a versatile spectrograph for the Hubble Space Telescope (HST) capable of maintaining or exceeding the spectroscopic capabilities of both the Goddard High Resolution Spectrograph (GHRS) and the Faint Object Spectrograph (FOS) over the broad bandpass extending from the ultraviolet (115 …

An IUE Spectroscopic Study of the Ultra-Short-Period Dwarf Nova T Leonis in Outburst

Sion, E. M.; Huang, M.; Fabian, D. +2 more

The IUE archive contains numerous low-resolution spectra of dwarf novae in outburst but relatively little synthetic spectral analyses of them using realistic accretion disk models with spectral lines. We have examined a series of previously unstudied archival IUE low-resolution short-wavelength prime spectra of the SU UMa-type ultra-short-period d…

Separate Spectra of the Components of the Low-Mass BinariesRoss 614A,B and L722-22A,B

Hershey, John L.; Chance, Don R.

The Hubble Space Telescope Faint Object Spectrograph has been used to acquire separate spectra of each of the component stars in the binaries Ross 614A,B (Gl 234A,B) and L722-22A,B (GJ 1005). Spectral types have been determined for each: M4.0 V, M5.5 V, M3.5 V, and M5.0 V, respectively, relative to a series of ground-based CCD spectra, in the 6500…

Rotationally Broadened Synthetic Spectra for HST and IUE Observations of Exposed White Dwarfs in Cataclysmic Variables

Sion, E. M.; Nguyen, Quyen; Fabian, Dirk +2 more

In many dwarf novae during quiescence, the underlying white dwarf dominates the flux in the far ultraviolet. By observing these exposed degenerate stars with the Hubble Space Telescope Goddard High Resolution Spectrograph and Faint Object Spectrograph (HST GHRS and FOS), the white-dwarf rotation rates can be determined or constrained by fitting sy…

Asteroids as Far-Infrared Photometric Standards

Müller, Thomas G.