Search Publications
Extension of the Polar Coronal Hole Boundary into Interplanetary space
Howard, Russell A.; Habbal, Shadia Rifai; Woo, Richard +1 more
White-light measurements made by the SOHO LASCO C2 and C3 coronagraphs and the Mk III Mauna Loa K-coronameter, ranging from 1.15 to 30 Rsolar, have been combined with Kitt Peak daily He I 1083 nm coronal hole maps, and full Sun Yohkoh soft X-ray images, to show that the boundaries of polar coronal holes, as determined by measurements of…
ISO observations of globular clusters
Eyres, S. P. S.; Evans, A.; Odenkirchen, M. +2 more
We report ISO observations of globular clusters, from which we derive new upper limits on the masses of dust therein. Our observations do not confirm the claimed detection of dust in 47 Tuc by Gillett et al. (1988) and our limits generally support previous conclusions that globular clusters are deficient in intra-cluster dust grains. We find that …
SOHO/SUMER observations and analysis of hydrogen Lyman lines in a quiescent prominence
Heinzel, P.; Schmieder, B.; Rudawy, P. +1 more
A quiescent prominence was observed in June 1997 by instruments onboard the SOHO spacecraft: the Solar Ultraviolet Measurements of Emitted Radiation (SUMER), Coronal Diagnostic Spectrometer (CDS) and Extreme-Ultraviolet Imaging Telescope (EIT), along with the coronagraph of the Wrocław University Observatory at Bialków and the spectrograph of the …
Ultraviolet and Optical Observations of a Coronal Transient with SOHO
Thompson, B. J.; Raymond, J. C.; Modigliani, A. +7 more
A coronal transient was observed on 1997 March 6 at 1.6 Rsolar over an active region on the east limb. We observed both the edge of horizontally compressed gas and the diffuse curtain of coronal material. The region was monitored for 4 hr, and the H I Lyα, O VI λλ1031.91, 1037.61, N V λλ1242.80, 1238.80, and O V] λ1218.35 lines were det…
Near-Infrared and Ultraviolet Spectrophotometry of Symbiotic Novae
Erwin, Peter; Rudy, Richard J.; Puetter, R. C. +3 more
In this paper we present an atlas of near-infrared spectrophotometry of symbiotic novae and report results from nearly contemporaneous IUE observations. The data cover RT Ser, AG Peg, V1016 Cyg, V1329 Cyg, HM Sge, and Pu Vul, most of the known symbiotic novae that are observable from the northern hemisphere. Emission-line strengths for both spectr…
Spectroscopy of the post-AGB star HD 101584 (IRAS 11385-5517)
Pottasch, S. R.; García-Lario, P.; Parthasarathy, M. +2 more
From an analysis of the spectrum (4000 Ä to 8800 Ä) of HD 101584 it is found that most of the neutral and single ionized metallic lines are in emission. The forbidden emission lines of [OI] 6300 Ä and 6363 Ä and [CI] 8727 Ä are detected, which indicate the presence of a very low excitation nebula. The Hα , FeII 6383 Ä, NaI D1, D2
The 10 GHz-10 THz spectrum of a normal spiral galaxy
Braine, J.; Hughes, D. H.
We present a complete FIR spectral energy distribution of a normal spiral disk. A full grating scan, from 43-189 mu m, centered on the nucleus of NGC 4414 was made with the ISO Long Wavelength Spectrometer (LWS). The mid-IR to millimeter continuum of NGC 4414 can be modeled with thermal dust emission from a warm component at 69 K and a cool compon…
Chemical Abundances of the Planetary Nebula IC 4634 and Its Central Star
Feibelman, Walter A.; Hyung, Siek; Aller, Lawrence H.
We have measured the spectral line intensities of the metal-poor planetary nebula IC 4634. Using a photoionization model calculation, we try to fit the optical and UV region spectra, i.e., Hamilton echelle and IUE observations. From direct images, one expects complicated density variations, but the model predicts a range in densities that may be s…
The Off-Limb Behavior of the First Ionization Potential Effect in T>5×105 K Solar Plasmas
Lemaire, P.; Drake, J. J.; Feldman, U. +1 more
We investigate the behavior of the solar first ionization potential (FIP) effect (the abundance enhancement of elements with first ionization potential of less than 10 eV in the corona with respect to photospheric values) with height above the limb in a region of diffuse quiet corona observed by the SUMER instrument on SOHO, with emphasis on so-ca…
Spectroscopic Observations of the Planetary Nebula NGC 6818
Feibelman, Walter A.; Hyung, Siek; Aller, Lawrence H.
NGC 6818 is a bright, high-excitation, fairly regular, planetary nebula with a rather rich spectrum. Its rather unusual kinematical structure, studied by Wilson, Weedman, and particularly by Sabbadin, is of special interest. We are here primarily concerned with its high-resolution spectrum as revealed by the Hamilton Echelle Spectrograph at Lick O…