Search Publications
Missions
Journals
Publication Years
HST/STIS UV Spectroscopy of Two Quiescent X-Ray Novae: A0620-00 and Centaurus X-4
Remillard, Ronald A.; McClintock, Jeffrey E.
In 1998 we made UV spectroscopic observations with HST/STIS of A0620-00 and Cen X-4, which are two X-ray novae (also known as soft X-ray transients). These binary systems are similar in all respects except that the former contains a black hole and the latter contains a neutron star. A UV spectrum (1700-3100 Å) is presented for the quiescent state …
Hubble Space Telescope Photometry of the Metal-rich Globular Clusters NGC 6624 and NGC 6637
Da Costa, Gary S.; Demarque, Pierre; Christian, Carol A. +3 more
We have observed the metal-rich globular clusters NGC 6624 and NGC 6637 (M69) using the planetary camera of the WFPC2 on the Hubble Space Telescope (HST). Observations of the Ca II triplet lines in giant stars in these clusters show that NGC 6624 and NGC 6637 have metallicities on the Zinn and West scale of [Fe/H]=-0.63+/-0.09 and -0.65+/-0.09, on…
Helioseismic Holography of Active-Region Subphotospheres - (Invited Review)
Braun, D. C.; Lindsey, C.
The development of solar acoustic holography has opened a major new diagnostic avenue in local helioseismology. It has revealed `acoustic moats' surrounding sunspots, `acoustic glories' surrounding complex active regions, and `acoustic condensations' suggesting the existence of significant seismic anomalies up to 20 Mm beneath active-region photos…
A Uniform Analysis of Boron in F and G Disk Dwarfs fromHubble Space Telescope Archival Spectra
Cunha, Katia; Smith, Verne V.; Lambert, David L. +1 more
The boron abundance is derived for 14 near-solar metallicity F and G dwarfs from the archived data set of spectra obtained with the Hubble Space Telescope Goddard High Resolution Spectrograph in the region of the B I resonance line near 2497 Å. These abundances are derived in a uniform way with respect to recent work on solar boron. The synthetic …
Measurements of the Diffuse Ultraviolet Background and the Terrestrial Airglow with the Space Telescope Imaging Spectrograph
Ferguson, Henry C.; Brown, Thomas M.; Gardner, Jonathan P. +3 more
Far-UV observations in and near the Hubble Deep Fields demonstrate that the Space Telescope Imaging Spectrograph (STIS) may obtain unique and precise measurements of the diffuse far-ultraviolet background. Although STIS is not the ideal instrument for such measurements, high-resolution images allow Galactic and extragalactic objects to be masked t…
Rapidly oscillating Ap stars versus non-oscillating Ap stars
Hubrig, S.; North, P.; Mathys, G. +1 more
The positions in the HR diagram and the kinematic characteristics of rapidly oscillating and non-oscillating chemically peculiar stars are obtained using new Hipparcos proper motions and parallaxes, and our own radial velocity measurements. We find that rapidly oscillating stars, as a group, are (-0.47 +/- 0.34) mag above the zero-age main sequenc…
Mapping Infrared Enhancements in Closely Interacting Spiral-Spiral Pairs. I. ISO CAM and ISO SWS Observations
Xu, Cong; Gao, Yu; Lu, Nanyao +3 more
Mid-infrared (MIR) imaging and spectroscopic observations are presented for a well-defined sample of eight closely interacting (CLO) pairs of spiral galaxies that have overlapping disks and show enhanced far-infrared (FIR) emission. The goal is to study the star formation distribution in CLO pairs, with special emphasis on the role of ``overlap st…
Solar Magnetoconvection - (Invited Review)
Hurlburt, N. E.; Matthews, P. C.; Rucklidge, A. M.
In recent years the study of how magnetic fields interact with thermal convection in the Sun has made significant advances. These are largely due to the rapidly increasing computer power and its application to more physically relevant parameters regimes and to more realistic physics and geometry in numerical models. Here we present a survey of rec…
The Galactic disk: study of four low latitude Galactic fields
Vallenari, A.; Schmidtobreick, L.; Bertelli, G.
We present deep V and I photometry of stellar fields in four previously unstudied low latitude regions of the Galactic disk. All observed fields are located at the western side of the Galactic Center in the direction of the Coalsack-Carina region. They are chosen on the large scale surface photometry of the Milky Way (Hoffmann et al., 1998 and Kim…
Element abundances in cool white dwarfs. I. The DZA white dwarfs L 745-46A and Ross 640
Wolff, B.; Koester, D.
The standard explanation for the presence of photospheric metals in white dwarfs of spectral type DZ and related types is a combination of episodic accretion from the interstellar medium and diffusion of heavy elements downwards in the atmosphere on time scales of typically 106 years. Much of the empirical data on atmospheric parameters…