The EUVE End-of-Mission Conference: Abstracts

1.1
Stuart Bowyer
Space Siences Laboratory
Univ. of California
talk: A Brief Overview of the History of EUVE and Selected Scientific Results
abstract: In retrospect, the development of the Extreme Ultraviolet Explorer was an obvious next step in NASA's exploration of the Universe. In reality, NASA's endorsement of this mission was based on the Berkeley development of creative, inexpensive EUV instrumentation, scientific opportunism, political maneuvering, and luck. Long forgotten moments of peril will be recalled. A few highlights of the scientific results from EUVE will be presented.
category: other
topic: other

2.1
Aaron Golden
National University of Ireland
talk: 'For now we see through the ISM, darkly...' - EUVE's View of Neutron Stars
abstract: The EUV region remains a critically important window as regards the study of neutron star astrophysics, particularly when combined with other multiwavelength datasets. EUVE's observations were unique because it's instrumentation was specifically designed and optimised for the detection of blackbodies as cool as 10^5 K and differentiate among low absorption column values N_H < 10^20 cm^-2 - both these parameters are characteristic of nearby cooling neutron stars. In this talk I review the observational results and scientific implications of EUVE's observation programme of these objects. In addition I highlight the impact the spacecraft has made in the study of neutron star binaries, in particular the accretion processes of X-ray neutron star/black hole binary systems. I will conclude my talk by asserting the relevance and need for a subsequent EUV platform to consolidate and extend the enormous acientific potential that we have only been able to glimpse with EUVE.
category: scientific legacy of EUVE
topic: compact objects

2.2
Jean Dupuis
Space Sciences Laboratory
University of California
talk: White Dwarfs after EUVE
abstract: EUVE has made a significant contribution to our understanding of hot white dwarf stars. I will present a review of some of the key results obtained by EUVE on single hot white dwarf stars and discussed how our knowledge about them has evolved.

In particular, I will discuss about EUV spectroscopy of hot DAs and what we have learned from the presence of metals in their atmospheres. I will also discuss about the numerous ultra-massive white dwarfs found by EUVE and ROSAT and their possible origin. I also intend to discuss the observation of EUV variability in the white dwarf GD 394 and present some more recent results about this peculiar object.
category: scientific legacy of EUVE
topic: compact objects

2.3
Matt Burleigh
Dept. of Physics and Astronomy
University of Leicester
talk: White Dwarfs in Sirius-like Binaries
abstract: Through the EUVE and ROSAT WFC surveys a significant number of previously unknown Sirius-like binary systems have been identified. In these systems the optical flux is dominated by the main sequence or giant companion (spectral type B-K). The white dwarf's presence is inferred from the soft X-ray and EUV photometric colours, and the identifcations were later confirmed through far-UV spectroscopy or, in the case of the WD+B star pairs, through spectroscopy with EUVE. I will emphasise the importance of these systems in studies of binary evolution and for studies of white dwarfs themselves. For example, the WD+B star pairs place an observational lower limit on the maximum mass for white dwarf progenitors, and all of these binaries can potentially be used to investigate the theoretical WD mass-radius relation. I will also present some of the latest work on the systems, including far-UV imaging with HST to try and resolve some of the pairs, and far-UV spectroscopy with FUSE to determine the white dwarfs' temperatures, gravities and masses.
category: scientific legacy of EUVE
topic: compact objects

2.4
Raymond Cruddace
Naval Research Laboratory
talk: Observation of the White Dwarf G191-B2B with a High-Resolution EUV Spectrometer
abstract: The authors are: R.G.Cruddace, H.Gursky, M.P.Kowalski, D.J.Yentis (NRL), M.A.Barstow, N.P.Bannister (University of Leicester), J.S.Lapington (Mullard Space Science Laboratory), T.W.Barbee Jr., J.F.Kordas (Lawrence Livermore National Laboratory) Future EUV missions should include high- resolution spectrometers, permitting use of the full range of spectroscopic diagnostics, in particular measurement of line profiles and Doppler shifts. We describe such a high- resolution instrument, which employs multilayer-coated ion-etched grating optics in a normal-incidence configuration, and which has been flown successfully on a NASA Black Brant IX sounding rocket mission. A spectrum of the white dwarf G191-B2B was obtained. The first results will be presented at the meeting.
category: other
topic: compact objects

2.5
Denis Leahy
Dept. Physics and Astronomy
University of Calgary
poster: Implications of EUVE Observations of Her X-1
abstract: Observations of Her X-1 by the Extreme Ultraviolet Explorer (EUVE) have been made while Her X-1 is in its normal 35-day cycle state and also while it is in it anomalous low state. Here the normal 35-day cycle state observations are discussed. The 35-day cycle in hard x-ray intensity: "Main High state -- low state -- Short High state -- low state" is caused by a tilted-twisted precessing accretion disk. EUVE observed Her X-1 in late Main High state, low state, early Short High state and late Short High state. Here is summarized what has been learned from the EUVE observations of Her X-1 during its normal 35-day cycle. The low state and late Short High state emission gave the first evidence that EUV emission is primarily due to reflection from the companion star HZ Her. The early Short High state emission is pulsed and closely resembles the 2-12 keV X-ray early Short High state lightcurve. This shows that the EUV emission, like the X-ray emission, originates near the neutron star Here is summarized what has been learned from the EUVE observations of Her X-1 during its normal 35-day cycle. The low state and late Short High state emission gave the first evidence that EUV emission is primarily due to reflection from the companion star HZ Her. The early Short High state emission is pulsed and closely resembles the 2-12 keV X-ray early Short High state lightcurve. This shows that the EUV emission, like the X-ray emission, originates near the neutron star. The early Short High state EUV spectrum is consistent with a blackbody of temperature 0.13 keV and radius 230 km. Thus the spectrum and pulse shape are similar to that in the soft X-rays (0.1 -1 keV). The most likely origin of the EUV emission is reprocessed X-rays from the inner edge of the accretion disk.
category: EUVE new discoveries
topic: compact objects

2.6
David Sing
Lunar & Planetary Lab.
University of Arizona
poster: Linking Flux in UV and Optical Wavelengths per Photometric Calibration: DA White Dwarfs and EUVE
abstract: The direct link between the absolute photometric calibration of the EUVE spectrometers and absolute fluxes at UV and optical wavelengths is investigated. EUVE observations of a select set of DA white dwarfs, covering a wide range of stellar temperatures, are compared with the observed UV and optical fluxes for these stars through the use of self consistent model atmospheres covering the entire EUV to optical energy distribution. Co-Authors: D. Sing J.B. Holberg J. Dupuis
category: scientific legacy of EUVE
topic: compact objects

3.1
Christopher Mauche
LLNL
talk: Disk-Accreting Cataclysmic Variables in the EUV
abstract: Because of its spectroscopic capability, long look times, and fast response time to target-of-opportunities, EUVE has produced significant advancements in our understanding of the EUV/soft X-ray emission of disk-accreting cataclysmic variables. I will review the state of our understanding of such systems prior to EUVE, advancements in our understanding based on EUVE data, and areas where further research is needed (i.e., what we knew, what we now know, and what we don't yet know).
category: scientific legacy of EUVE
topic: CVs

3.2
Paula Szkody
Dept. of Astronomy
U of Washington
talk: The Impact of EUVE on Magnetic CVs
abstract: EUVE has played a pivotal role in providing information on the heating effects occurring in accreting white dwarfs with substantial magnetic fields. Time-resolved light curves combined with spectral information give clues to the geometry, size, temperature and composition of the areas receiving the accreted material. This information, combined with data from other wavelengths, results in our enhanced knowledge of accretion in high magnetic fields. The data available from EUVE will be summarized, as well as future directions needed to resolve remaining problems.
category: scientific legacy of EUVE
topic: CVs

3.3
Kunegunda Belle
Planetary Science Institute & University of Wyoming
talk: A Multi-Wavelength Study of the Intermediate Polar EX Hydrae
abstract: On May 5, 2000, we began a large multi-wavelength campaign to study the intermediate polar, EX Hydrae. The simultaneous observations from six satellites and four telescopes were centered around a one million second observation with EUVE. Although EX Hydrae has been studied previously with EUVE, our observations present new results and challenge the current IP models. Two previously unseen dips in the light curve are reminiscent of the stream dips seen in polar light curves. These dips are generally attributed to an eclipse of the accretion pole by the near field accretion stream. Also of interest is the temporal extent of the bulge eclipse; approximately 0.5 in phase. This implies that the bulge extends over half of the accretion disk. We propose that the magnetic field in EX Hydrae is strong enough (a few MG) to begin pulling material directly from the outer edge of the disk, thereby forming a large accretion curtain which would produce a very broad bulge eclipse. This could also result in magnetically controlled accretion streams originating from the outer edge of the disk. Our simultaneous full phase coverage UV (HST) and X-ray (RXTE, Chandra, USA) observations, along with those from the EUVE, will enable us to deduce and understand the complex accretion geometry within EX Hydrae. This work will provide a greater understanding of the accretion geometry of EX Hydrae and will lend insight into other magnetic cataclysmic variables.
category: multi-wavelength
topic: CVs

3.4
Steve Howell
Astrophysics Group
Planetary Science Institute
poster: HU Aqr: Simultaneous EUV and IR Observations
abstract: This poster will present the results of an observational program to simultaneously monitor polars in both the EUV and the IR spectral ranges. Amazingly, the flux levels and light curve shapes are highly correlated although the cause for such correlation can only be speculated on.
category: multi-wavelength
topic: CVs

4.1
Suzanne Hawley
Astronomy
University of Washington
talk: Multiwavelength Observations of Stellar Flares
abstract: I will discuss EUVE observations of flares on M dwarfs taken as part of multiwavelength campaigns during 1993 and 2000, and highlight advances in our understanding of flare physics that have resulted from these data.
category: multi-wavelength
topic: cool stars

4.2
Nancy Brickhouse
CfA
talk: EUVE and Chandra: The Emission Line Project Connection
abstract: Determining the structure and abundances of cool star coronae is key to understanding the physical processes of magnetic confinement, heating, material transport and winds. Spectral diagnostics from the ultraviolet to X-ray constitute the critical observational data, and thus we must ensure that the plasma spectral models needed to interpret spectra are accurate and robust. EUVE studies of cool stars have demonstrated a diversity of coronal phenomenology, yet their interpretation in terms of physical processes has lagged in part because of concerns about the accuracy of spectral diagnostics. New observations using the gratings on Chandra and XMM-Newton are providing high spectral resolution, however, with the recurrence of questions about the adequacy of the diagnostics.

We report progress on the Emission Line Project, a collaborative effort to improve the spectral models for collisionally ionized plasmas. Astrophysical observations are being used, in conjunction with laboratory and theoretical atomic studies, to benchmark these models and determine critical needs. In order to exploit the cool star EUV and X-ray data for these purposes we must understand the extent to which common simplifying assumptions (e.g. coronal equilibrium, negligible optical depth) apply. We will revisit EUVE targets in view of what we are learning from Chandra about their structure and abundances and the state of the plasma codes.
category: none
topic: cool stars

4.3
Edward Guinan
Dept. of Astronomy and Astrophysics
Villanova University
talk: The Sun in Time: EUVE and FUSE Observations of Solar-type Stars of Different Ages
abstract: The Sun in Time: EUVE and FUSE Observations of the Solar Analogs with Different Ages.

We report on the initial results of EUVE and FUSE observations of an homogenous sample of single G0V - G5V stars with well known rotation periods and ages. These stars are nearby and range in age from ~100 Myr to ~ 8.5 Gyr and with corresponding rotation periods that range from ~ 2.5d to ~ 35d. This program is part of a comprehensive study of the "Sun in Time" across the electromagnetic spectrum. The EUVE and FUSE observations cover the wavelength region from 80 A to 1190 A - a spectral region is that is rich in important transition region (TR) and coronal emission lines. The EUVE and FUSE observations fill a critical wavelength and energy gap in the "Sun in Time" program and complement observations of the same stars in the X-ray region (corona) with ROSAT, SAX, ASCA, XMM, and Chandra, in the UV-NUV (TR and chromosphere) made with IUE and HST, and at cm-radio wavelengths (non-thermal corona) obtained with the VLA. In addition, optical photometry of most stars has been carried out for over 10 years (using robotic telescopes). The photometry permits the rotation periods, activity cycles, and starspot fill-factors and differential rotation of the program stars to be determined. Overall, the "Sun in Time" program is central to the understanding of the evolution of magneto-dynamic atmosphere phenomena, and the associated high energy emissions of the Sun and of solar type stars.

For the stars in the sample we also discuss the crucial question of the influence of the young Sun's observed strong X-ray, EUV and FUV emissions have on the developing planetary system - in particular on the photochemical and photoionization evolution (and possible erosion) of early planetary atmospheres and ionospheres. To this end, we are constructing spectral irradiance tables for the Sun at different ages (flux at 1.0 AU; 1A to 5500A). We present the results obtained so far and also discuss implications that the young Sun's enhanced high energy radiation (which includes energetic flaring) may have had on the formation and development of life on Earth over ~ 3.5 Billion years ago.

This research is supported by NASA FUSE Cycle 1 & 2 Grants NAG 5-8985 and NAG 5-10387 and EUVE Mini-grant SA2085-26310 which we gratefully acknowledge.
category: scientific legacy of EUVE
topic: cool stars

4.4
Andrea Dupree
Smithsonian Astrophysical Observatory: CfA
talk: EUVE and FUSE: Coronal Connections
abstract: Analysis of the extreme ultraviolet spectra of cool stars from EUVE reveals a surprising new view of stellar coronas. Small structures with high density and temperature are imbedded in many coronas of both single and binary stars. These structures, revealed by a well-defined increase in the emission measure distribution over a narrow temperature range (~10^7 K), are clearly stable, and demand high magnetic fields and continuous energy input for their existence. Far ultraviolet spectra from FUSE contribute to the definition of coronal structure with the identification of Fe XVIII in the spectra of Capella and other stars. FUSE spectra have sufficient resolution to establish the source of emissions by radial velocity identification. FUSE spectra additionally reveal species formed at temperatures below Fe IX found in EUVE spectra enabling extension of a well-defined emission measure distribution to lower temperatures through the transition region. Examples of the EUVE/FUSE connection will be chosen from several favorite targets.
category: none
topic: cool stars

4.5
Rachel Osten
Center for Astrophysics and Space Astronomy
University of Colorado
poster: Four Years of Multiple Wavelength Observations of the RS CVn System HR 1099 (V711 Tau)
abstract: R. A. Osten, A. Brown, T. R. Ayres, J. L. Linsky

(multi-wavelength work)

We report on four years of multiple wavelength observations of the RS CVn binary system HR 1099 (V711 Tau) from 1993, 1994, 1996, and 1998. The campaigns are made up of a core of EUVE and radio observations for all four years, plus ultraviolet (IUE + HST) and X-ray (ASCA, RXTE, and BeppoSAX) coverage. We report on the changing activity of the system as recorded in the EUV and radio -- in 1993, 1994, and 1996, the system spent > 75% of the duration of the EUVE observations in a flaring state, while in 1998 > 90% of the observation appeared to be non-flaring. Evidence in the EUV of non-solar flare morphologies is present, with rise times equal to the decay timescales; there is also evidence for a "four step" flare process which encompasses a slow rise, fast rise, fast decay, and slow decay. Higher energy X-ray observations confirm and extend the activity seen in the EUV. Radio bursts are prevalent during the four years of observations, with large negative circular polarizations at 20 cm indicative of plasma emission occurring during flares. Radio, UV, EUV, and X-ray flares are generally well-correlated, with radio bursts preceding higher energy flares in time. We discuss the spectral signatures of the flares as recorded in different wavelength regions, the existence of ``quiescence'', and the implications for flare studies of these multi-wavelength observations.

R. A. Osten acknowledges the support of NASA GSRP fellowship, grant NGT5-50241.
category: multi-wavelength
topic: cool stars

5.1
Warren Moos
Physics and Astronomy
Johns Hopkins University
talk: The FUSE Mission and EUVE
abstract: The Far Ultraviolet Spectroscopic Explorer (FUSE) bandpass (903 - 1179 A) is close to that of EUVE. As a consequence, many of the most important FUSE investigations are related to, and build on previous studies by EUVE. I will illustrate this relationship with illustrations from studies of white dwarfs, the interstellar medium and solar system objects.
category: none
topic: other

5.2
Matt Burleigh
Dept. of Physics and Astronomy
University of Leicester
talk: Highlights from a decade of ROSAT Wide Field Camera EUV observations
abstract: After it had completed the first EUV all-sky survey in 1990-1991, the ROSAT Wide Field Camera began a programme of pointed observations which lasted until the mission was terminated in 1999. I will present highlights from this phase of the mission, including the first EUV image of a comet (Hyakutake), the detection of bright transient events (e.g. the mysterious RE J1255+266, and the CV SW UMa in super-outburst), and the detection of an isolated old neutron star. All of the WFC data, including the pointed observations, survey data products, and source lists from both phases of the mission, are available from the LEDAS database at ledas-www.star.le.ac.uk.
topic: other
category: other

5.3
Isabel Hawkins
Space Sciences Laboratory
UC Berkeley
talk: From the Extreme to the Ultimate Education and Public Outreach Program
abstract: EUVE established one of the first comprehensive education and public outreach efforts tied to a NASA Space Science satellite mission. EUVE scientists and staff developed a model program with many features that influenced the structure and implementation of the overall NASA Office of Space Science Education and Public Outreach effort. Key components such as partnering with science museums and K-12 institutions, responsiveness to user needs, significant involvement of the space science community, evaluation of impact, and innovative uses of information technology were pioneered through the EUVE effort. I will describe lessons learned as well as the successful strategies we used in evolving the EUVE education and public outreach program into the Center for Science Education @ Space Sciences Laboratory.
category: other
topic: other

5.4
Martin Barstow
Department of Physics and Astronomy
University of Leicester
talk: EUV astronomy: do we have a future?
abstract: EUVE and other missions, such as the ROSAT WFC, have left a tremendous legacy on which we all would like to build. The termination of the EUVE mission has left glaring hole in the spectral coverage of space missions and our community without a general observatory class facility. So where do we go from here? What scientific problems should (or could) a new GO space mission address and what are the technical requirements for such a mission?
category: future EUV missions
topic: other

5.5
Damian Christian
Eureka Scientific

poster: New Results from the last years of the EUVE Right Angle Program
abstract: We present preliminary results of our search for new sources in the EUVE Right Angle Program (RAP) data taken since the Second RAP catalog (November 1998), and spanning until the end of the EUVE mission. The EUVE all-sky survey telescopes (also known as scanners) were mounted at right angles to the Deep Survey and spectrometer instruments, and obtained photometric data in four bands centered at ~100 Angstroms (Lexan/B), ~200 Angstroms (Al/Ti/C), ~400 Angstroms (Ti/Sb/Al), and ~550 Angstroms (Sn/SiO). This allowed the Right Angle Program to accumulate data serendipitously during pointed spectroscopic observations. The long exposure times possible with RAP observations provide much greater sensitivity than the all-sky survey. It is expected analysis of the most recent RAP data once combined with the EUVE all-sky survey, Lampton faint list, and previous RAP catalogs will bring the total number of EUVE sources to over 1200. In addition to new source detections and identifications, we will also present light-curves and variability measurements for the brighter sources.
category: EUVE new discoveries
topic: other

6.1
Barry Welsh
talk: EUVE Mission Special
abstract: (not available at this time)
category: none
topic: none

6.2
Martin Sirk
Space Sciences Laboratory
University of California, Berkeley
poster: The Soft X-Ray Sources Detected with EUVE
abstract: The soft X-ray response for each EUVE imaging telescope is quantified by combining ground based calibration data, theoretical models, and in-flight observations of the bright soft X-ray source Sco X1. Several soft X-Ray sources have been observed by EUVE in more than one passband allowing crude two color photometry. The western half of the Cygnus Loop SNR was obeserved for 200 k sec in a RAP pointing, and the Vela SNR was easily detected in the All Sky survey and in a 100 ksec DS observation. The AGN sources 3C 273 and Mrk 501 were each observed for 11 ksec in Scanner pointings. The peak wavelength for each source is determined from the observed passband ratios. All four sources are distinctly softer than Sco X1, which is known to have no flux longward of 50 Ang. Thus, these objects are genuine EUV sources and not merely out-of-band hard X-Ray detections.
category: none
topic: other

6.3
Ellie Arroway
no affiliation

poster: EUVE Detector Spikes: An Extreme Explanation
abstract: (not available at this time)

7.1
Herman Marshall
Eureka Scientific, Inc.

talk: The Average Extreme Ultraviolet Spectrum of Active Galaxies
abstract: Using long EUVE observations of six active galactic nuclei (AGN), we have determined the composite spectrum in the extreme ultraviolet band. While individual sources show possible evidence for emission lines, the composite spectrum shows only a smooth continuum, indicating that there are no emission lines that are common to all active galaxies
category: scientific legacy of EUVE
topic: extragalactic

7.2
Rick Edelson
Astronomy Dept
UCLA
talk: Simultaneous EUVE and ASCA Monitoring of Ton S180
abstract: Simultaneous EUVE and ASCA Monitoring of Ton S180
abstract: I will present results from simultaneous EUVE and ASCA monitoring of the steep X-ray spectrum Seyfert 1 galaxy Ton S180. This is ideal for such monitoring because of its brightness and low N_H. However, problems with the background limited usefullness of the EUVE data. Nonetheless, these results suggest that it is possible to seperate soft and hard components with arbitrary shapes on the basis of spectral variability.
category: multi-wavelength
topic: extragalactic

7.3
Max Bonamente
University of Alabama in Huntsville (UAH)
talk: The EUV and soft X-ray excess in clusters of galaxies
abstract: Many clusters of galaxies reveal substantial EUV and soft X-ray emission in excess of the contribution from the hot intra-cluster medium. I will present recent observations with the Deep Survey instrument of EUVE, and investigations with archival ROSAT/PSPC and SAX/LECS data. Future plans aiming to understand the nature of the soft component will also be presented.
category: EUVE new discoveries
topic: extragalactic

7.4
James Overduin
Dept. of Physics
Waseda University
talk: Background Radiation from New Dark Matter Candidates
abstract: Many theoretical dark matter candidates are unstable to photon decay and can hence be looked for in the extragalactic background. The EUV background has proved particularly useful for two examples, the neutrino and the axion. I review these facts and move on to consider newer candidates such as the higher-dimensional "heavy gravitons" predicted by brane world theory.
category: none
topic: extragalactic

8.1
Rosine Lallement
Service d'Aeronomie, CNRS
talk: The Local Interstellar Cloud
abstract: I will review current knowledge about the characteristics of the interstellar gas surrounding the Sun, from observations of the flow of gas in the solar system and absorption towards the nearby stars, including EUVE white dwarfs data.
category: none
topic: ISM

8.2
John Vallerga
Space Science Lab
U.C. Berkeley
talk: The Interstellar Wind through the Solar System as measured by EUVE
abstract: (not available at this time)
category: continuing EUVE work
topic: ISM

8.3
Barry Welsh
Space Sciences Laboratory UC Berkeley
talk: The Local Interstellar Cavity
abstract: We present an overview of the impact of EUVE on the study of the local interstellar cavity. In particular, we demonstrate how the detection of extragalactic sources by EUVE led to the discovery of the Local Interstellar Chimney.
category: multi-wavelength
topic: ISM

8.4
Jeffrey Bloch
Los Alamos National Laboratory
talk: Limits on Emisson from Fe IX - X from the Hot Local Interstellar Medium
abstract: The majority of the emitted power from an optically thin million degree plasma such as the one thought to produce the soft x-ray background originates in the EUV band at wavelengths longer 17.0 nm. Lines from Fe VIII - Fe X dominate the emission in this region. This presentation describes the analysis of three years of data from the wide angle multilayer mirror telescopes on ALEXIS mission in search of this flux. We find only upper bounds for this Fe line emission at levels significantly below what is predicted by current plasma emission codes with normal cosmic abundance and equilibrium parameters that fit the higher energy emission measured by the Wisconsin sky survey, the ROSAT XRT, and the SAS-3 soft x-ray instrument. Efforts using EUVE's Medium Wavelength Spectrometer also failed to detect these Fe Lines. We discuss the implications of this finding including the possibilities that the hot component of the local interstellar medium has depleted abundances and/or that non-equilibrium conditions exist. This work was supported by the Department of Energy.
category: currently-approved EUV missions
topic: ISM

8.5
Mark Hurwitz
Space Sciences Laboratory
UCB
talk: The Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)
abstract: The Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) is a University-Class Explorer (UNEX) mission funded by NASA. It will carry out all-sky spectroscopy of the diffuse background at wavelengths from 90 to 260 � with a peak resolution of /150 (about 0.5 eV). CHIPS data will help scientists determine the electron temperature, ionization conditions, and cooling mechanisms of the million-degree plasma believed to fill the local interstellar bubble. The majority of the luminosity from diffuse million-degree plasma is expected to emerge in the poorly-explored CHIPS band, making CHIPS data of relevance in a wide variety of Galactic and extragalactic astrophysical environments. The CHIPS instrument will be carried into space aboard CHIPSat, a dedicated spacecraft to be built by SpaceDev, Inc., and launched from the second stage of a Delta rocket in 2002.
category: currently-approved EUV missions
topic: ISM

8.6
Jerry Edelstein
Space Sciences Lab
University of California
talk: SPEAR: Mission for the Hot ISM
abstract:
J. Edelstein, E. Korpela,(SSL, UCB) W.V Dixon (JHU), K.W. Min (KAIST, Korea), W.H. Han, (KAO, Korea)

The SPEAR Mission of Opportunity will measure the physics of transitional, hot (T = 104.5 ^� 106 K) interstellar medium (ISM) in our Galaxy. SPEAR, the primary payload on the KAISTSAT-4 mission (2003 launch), will map diffuse FUV emission in the sky. Spectral imaging at arcminute scales over the entire sky will allow for statistical comparisons with global tracers of the multi-phase ISM, and pointings will allow detailed studies of individual targets. The mission will test multi-phase models of the ISM and be used to examine hot gas interactions in superbubbles, to understand shock interactions between supernovae and the ISM, and to understand plasma phenomena found in galactic fountains and halos, active galaxies, galactic clusters, and possibly the intergalactic medium.
category: currently-approved EUV missions
topic: ISM

9.1
Carey Lisse
Department of Astronomy
Univeristy of Maryland at College Park
talk: The EUVE Comet Database
abstract: EUVE observations of cometary x-ray emission have spanned more than 10 years of time, from before the recognition of x-rays from comet Hyakutake in 1996 until mission end in 2000. More than 10 comets were detected by EUVE in the extreme ultraviolet and soft x-ray.

By comparing the results of these detections we can derive strong conclusions about the charge exchange mechanism and the solar wind driving the emission. We also discuss the possibility of searches for x-ray emission from other solar system bodies due to the same emission mechanism in light of the EUVE results for the Moon, Venus, Mars and Jupiter.
category: EUVE new discoveries
topic: solar system

9.2
Vladimir Krasnopolsky
Catholic University of America
talk: EUVE Observations of Comets With Spectrometers and DS
abstract: We observed 8 comets using the DS camera and three EUVE spectrometers, and detected X-ray emission in 5 comets. X-ray luminosities and their spatial distributions with a crescent-like structure were determined from the observations. The observed excellent correlation of X-ray luminosities with gas production rates in the comets and constant pe ak brightnesses scaled to heliocentric distanse require charge exchange of the solar-wind heavy ions as an excitation process and preclude excitation by electron impact and bremsstrahlung. Due to the close flyby of comet Hyakutake at 0.1 AU, its spectra a re of exceptionally high quality and exceed the currently published spectra of comets by a factor of 3 in resolving power and by two orders of magnitude in photon statistics. The spectra reveal for the first time the solar wind charge exchange emission lines. The most prominent lines are OV 215 A, CV 249 A, and HeII 304 A. Some other lines, which are of comparable strength, are blended. The OII lines at 538/539, 617, and 430/442 A are formed by photoionization of atomic oxygen similar to those in Earth's dayglow. The observed depletion of neon relative to the solar abundance by more than a factor of 2600 confirms the current view that Oort cloud comets formed in the Jupiter-Neptune region of the solar nebula.
category: EUVE new discoveries
topic: solar system

9.3
Randy Gladstone
Southwest Research Institute
talk: EUVE Observations of Jupiter and the Io Plasma Torus
abstract: Jupiter has the largest and by far the most energetic magnetosphere of all the planets in our solar system. Unlike the Earth's solar-wind-driven magnetosphere, Jupiter's magnetosphere is mostly internally powered, and is the best-observed analog we have of a pulsar. Its densest region, the Io Plasma Torus (IPT), can be directly imaged in the EUV and its plasma density, temperature, and composition deduced from its electron-impact line emission spectrum. Although the IPT is clearly supplied by oxygen and sulfur originating in the volcanos of Io, the pathway from Io to the torus is not well understood. EUVE was uniquely capable of measuring fundamental torus properties, such as electron temperature and oxygen ion abundances. During 1993-1999 EUVE provided invaluable data for addressing outstanding problems regarding the energetics, stability, and periodicities of the IPT, accumulating over 1500ks in observations.

In addition to learning about the IPT, EUVE observations of Jupiter have also monitored the brightness of the He 58.4nm airglow emission, which provides a useful diagnostic of turbulence in Jupiter's upper atmosphere. During the Shoemaker-Levy 9 impacts of July 1994 the 58.4nm emission, normally just barely detectable, was observed by EUVE to brighten dramatically as the exploding comet fragments raised large quantities of helium to high altitudes.
category: scientific legacy of EUVE
topic: solar system

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