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Vol 6, No. 3                 29 Mar 1996                    ISSN 1065-3597
	  (C) 1996, Regents of the University of California

Notes from the Editor
   by Brett A. Stroozas, ISO Manager

   Welcome to the electronic newsletter for NASA's Extreme Ultraviolet
Explorer (EUVE) satellite, compiled and published monthly by the
Integrated/Intelligent Science Operations (ISO) group at the Center for
EUV Astrophysics (CEA) at the University of California, Berkeley (UCB).
The contents of this issue of the EUVE electronic newsletter are as

 1. EUVE Science News
    1.1 Recent EUVE Science Highlights
    1.2 IAU Circular Regarding EUVE J2115-58.6
    1.3 Abstracts of Recently *Accepted* EUVE Papers
 2. EUVE Science Operations News
    2.1 Change in Data Recording Strategy -- Orbital Night Only
    2.2 CEA Proposal to "Outsource" EUVE Mission
    2.3 Upcoming Observation of Comet 1996 B2 (Hyakutake)
    2.4 Public Data Release for 1 Apr 1996
    2.5 On-Line Access to EUVE

To comment on or make suggestions for the EUVE electronic newsletter,
please send e-mail to (Internet).

   The EUVE observatory performed well throughout the month of Feb
1996, conducting observations of the following Guest Observer (GO)
targets (alternate name and spectral type information taken from the
SIMBAD or internal CEA databases; "NOIDs" are unidentified objects):

    Target          Alternate     Spectral       Observation
     Name             Name          Type         GMT Date(s)     Notes

   theta 1 Tau      EUVE J0428+159  K0IIIb  30 Jan - 01 Feb 1996  ---
   Algol            beta Per        B8V     01 Feb - 02 Feb 1996  ---
   Moon             --------        SolSys  02 Feb - 02 Feb 1996  ---
   Algol            beta Per        B8V     02 Feb - 07 Feb 1996  ---
   RE 0723-274      EUVE J0723-277  DA1     07 Feb - 07 Feb 1996  ---
   V1159 Ori        --------        DwNova  07 Feb - 09 Feb 1996  ---
   RE 0723-274      EUVE J0723-277  DA1     09 Feb - 12 Feb 1996  ---
   1229+204         --------        AGN     09 Feb - 12 Feb 1996  RAP
   BH CVn           HD 118216       F2IV    12 Feb - 21 Feb 1996  ---
   Survey           --------        ----    21 Feb - 23 Feb 1996  CAL
   V1159 Ori        --------        DwNova  23 Feb - 24 Feb 1996  ---
   44i Boo          HD 133640       G0V+    24 Feb - 25 Feb 1996  ---
   V1159 Ori        --------        DwNova  25 Feb - 26 Feb 1996  ---
   44i Boo          HD 133640       G0V+    26 Feb - 03 Mar 1996  ---

   Key to Notes:
	RAP = simultaneous Right Angle Program imaging observation
	CAL = star tracker calibration survey period

1. EUVE Science News

1.1 Recent EUVE Science Highlights
	by Dr. Pierre Chayer, EUVE/CEA Scientist

		 Discovery of Warm Gas in the Center
		    of the Virgo Cluster with EUVE

      Drs. Richard Lieu, Jonathan Mittaz, Stuart Bowyer, Felix
   Lockman, Chorng-Yuan Hwang, and Jurgen Schmitt performed an
   observation of the central region of the Virgo Cluster with the
   EUVE deep survey telescope.  A point source and and extended
   emission halo were clearly detected.  It is the first detection of
   cluster gas emission in the EUV.  Dr. Lieu and his collaborators
   show that the emission cannot be interpreted by the cluster gas at
   X-ray temperatures and propose a second gas component with
   temperature between 5E+5 and 1E+6 K.

1.2 IAU Circular Regarding EUVE J2115-58.6
	Excerpted from IAU Circular No. 6297, 29 Jan 1996

   N. Craig, University of California at Berkeley, reports: "An
optical counterpart for EUVE J2115-58.6 has been identified as a
magnetic CV, probably an AM Her-type cataclysmic variable.  The field,
centered at R.A. = 21h15m41s, Decl. = -58d40'48" (equinox 2000.0), was
observed as part of the EUVE Optical ID Campaign on 1995 Dec. 10.063 UT
with the 1.5-m telescope (Loral) at Cerro Tololo.  The proposed optical
counterpart, at R.A. = 21h15m41s, Decl. = -58d40'54", well within the
source error circle, is a star of estimated mv = 16.0.  The optical
spectrum clearly shows the characteristics of a cataclysmic-variable
spectrum, with the typical Balmer emission lines, as well as
lines of He I, Ca II and strong He II emission.  The continuum increases
sharply toward the blue at short wavelengths.  The CV EUVE J2115-58.6
was detected during the all-sky survey in the EUVE Lexan/B band
(5.8-17.4 nm, 0.07-0.21 keV) on 1992 Oct. 20, and also during the
gap-filling on 1993 Apr. 19.  A countrate of 0.05 cts/s is calculated.
Monitoring photometric and spectroscopic observations are urged."

1.3 Abstracts of Recently *Accepted* EUVE Papers

   Included below are abstracts of EUVE-related papers recently
*accepted* for publication.  For those papers authored by CEA
personnel, the CEA publication numbers are indicated.  Unless
otherwise noted, researchers may obtain preprints of the CEA papers by
sending an e-mail request containing the publication number(s) of
interest to

   Researchers are encouraged to contribute *accepted* EUVE-related
abstracts for inclusion in future editions of this newsletter;
abstracts or preprints will also be posted under the CEA WWW Home
Page.  Please send all abstracts or preprints to


Christopher W. Mauche
To appear in Astrophysical Journal Letters.

   Quasi-coherent oscillations have been detected in the extreme
ultraviolet flux of the dwarf nova SS Cygni during observations with
the Extreme Ultraviolet Explorer satellite of the rise and plateau
phases of an anomalous outburst in 1993 August and a normal outburst
in 1994 June/July. On both occasions, the oscillation turned on during
the rise to outburst and persisted throughout the observation. During
the 1993 outburst, the period of the oscillation fell from 9.3 s to
7.5 s over an interval of 4.4 days; during the 1994 outburst, the
period fell from 8.9 s to 7.19 s (the shortest period ever observed in
SS Cyg, or any other dwarf nova) within less than a day, and then rose
to 8.0 s over an interval of 8.0 days. For both outbursts, the period
P of the oscillation was observed to correlate with the 75-120 A count
rate I_(EUV) according to P is proportional to I_(EUV)^(-0.094).  A
magnetospheric model is considered to reproduce this variation. It is
found that an effective high-order multipole field is required, and
that the field strength at the surface of the white dwarf is 0.1-1 MG.
Such a field strength is at the lower extreme of those measured or
inferred for bona fide magnetic cataclysmic variables.


R.F. Malina
Submitted to International Astronautical Federation, Symposium: IAA
  11, Small Satellite Missions Symposium, Session: IAA 11.3, On Board
  Autonomous Systems for Small Satellites, 1995.  [CEA publication
  #677; not preprinted]

   The EUVE satellite was launched by NASA in 1992. In 1993, NASA
began to drastically reduce available funding for operations and
threatened early end of operations unless innovative lower cost
approaches to operating EUVE could be found.  This paper describes the
re-engineering of the EUVE science operations center that has been
successfully carried out.  The EUVE science operations center was
designed around the premise of around-the-clock staffing.  In late
1994, the EUVE science operation center was successfully moved to one
8-hour shift, 7-day a week operation with no loss of science return
and with increased payload safety.  In late 1995, the EUVE science
operations center will move to zero manned shifts.  This has been
carried out through the rapid infusion of new autonomous monitoring
software on the ground and increased on-board autonomy.  Commercially
available artificial intelligence software was augmented for the
EUVE-specific requirements.  In 1995, EUVE was designated by NASA-GSFC
as a flight operation innovation testbed.  This has allowed rapid
prototyping of software in a real operations environment and rapid,
safe, migration of new operation procedures and software into
operations use.  The EUVE innovation program was carried out with
innovative engineers at NASA, JPL, Ames Research Center, and GSFC.
The biggest impediment to moving from operations concepts based on
human availability and intervention to operations predicated on full
autonomy with human intervention only for anomaly response has been
institutional resistance not availability of low-cost technical


M. Mathioudakis
To appear in Astrophysical Letters and Communications, presented June
  1995 at the NATO ASI on Solar and Stellar MHD Flows in Crete,
  Greece. [CEA publication #703; not preprinted]

   The detection of a well-defined lower limit in the surface flux
versus color diagrams, and the fact that all late-type dwarfs examined
have chromospheric Mg II emission cores, shows that the formation of
chromospheres in late-type dwarfs is universal.  This result implies
that a basic, fundamental heating mechanism exists in the atmosphere
of late-type dwarfs.  Recent results in the extreme ultraviolet and in
X-rays have shown that low-activity dwarfs have detectable coronal
emission.  Their corona is characterized by relatively cool
temperatures, typically less than a few million degrees.  Current
theories of acoustic heating reproduce quite well the observational
parameters of low-activity dwarfs.  However, the basal emission could
also arise from a fundamental magnetic rather than acoustic heating
mechanism.  We review the observational properties of low-activity
dwarfs and compare them with current theories of atmospheric heating.


F.P. Keenan, V.J. Foster, J.J. Drake, S.S. Tayal, and K.G. Widing
Astrophysical Journal, 453, 906-910, 1995.  [CEA publication #708; not

   Recent R-matrix calculations of electron impact excitation rates
for Fe XIII are used to derive the theoretical electron density
sensitive emission line ratios R_1 = I(3s^2 3p^2 1D-3s3p^3 1D)/I(3s^2
3p^2 3P_2-3s3p^3 3P_2) = I(318.12 A)/I(320.80 A) and R_2 = I(3s^2 3p^2
1D-3s3p^3 1P)/I(3s^2 2p^2 3P_2-3s3p^3 3S) = I(256.42 A)/I(251.95 A),
which are found to be up to 70% different from earlier diagnostics.  A
comparison of the current line ratios with both solar flare and active
region observations, obtained by the Naval Research Laboratory's S082A
spectrograph on board Skylab, reveals generally good agreement between
densities deduced from Fe XIII and those estimated from diagnostic
line ratios in species formed at similar temperatures, such as
I(219.12 A)/I(211.32 A) in Fe XIV.  This provides experimental support
for the accuracy of the line ratio calculations, and hence the atomic
data adopted in their derivation.  In Extreme Ultraviolet Explorer
satellite (EUVE) spectra the Fe XIII emission lines are found to be
severely blended.  However, an analysis of these lines measured in the
spectra of Procyon and alpha Cen demonstrates that they still allow
very approximate values of the electron density to be inferred.
Moreover, it should be possible to increase the accuracy of the
measured line fluxes, and hence of the inferred densities, if longer
exposures of the stars concerned can be obtained.


G.F. Bignami, P.A. Caraveo, R. Mignani, J. Edelstein, and S. Bowyer
Astrophysical Journal Letters, 456, L111-L114, 1996.  [CEA publication

   A new set of ground-based optical, HST, UV, and EUVE data on
Geminga are presented.  The object, identified with a high proper
motion isolated neutron star (INS), is seen to emit thermal radiation
with a temperature in the range (2.2-2.8)E+5 K.  This is compatible
with the global thermal emission from the surface of a standard
neutron star of Geminga's spin-down age located at the distance of
about 160 pc, recently reassured through its annual parallax.  However,
in the "optical" (3400-8000 A) range, combined ground-based and HST
data suggest the presence of a spectral feature (either in emission or
possibly in absorption) superimposed on the Rayleigh-Jeans continuum.
Its simplest interpretation could be related to an ion (H or He)
cyclotron frequency for the object's canonical magnetic field of
1.5E+12 G.  This is the first observational evidence for an optical
spectral feature in an INS.  A search for a similar effect should also
be feasible for PSR 0656+14, the only other INS possibly showing
optical thermal emission from its surface.


S. Bowyer and R. F. Malina
Advances in Space Research, 16, 15, 1995.  [CEA publication #715; not

   We present a few scientific highlights from the Extreme Ultraviolet
Explorer (EUVE) all-sky and deep surveys, from the EUVE Right Angle
Program, and from the EUVE Guest Observer Program. The First EUVE
Source Catalog includes 410 extreme ultraviolet (EUV) sources detected
in the initial processing of the EUVE all-sky data. A program of
optical identification indicates that counterparts include cool star
coronae, flare stars, hot white dwarfs, central stars of planetary
nebulae, B star photospheres and winds, an X-ray binary, extragalactic
objects (active galactic nuclei, BL Lacertae), solar system objects
(Moon, Mars, Io,), supernova remnants, and two novae.


B. C. Monsignori Fossi, M. Landini, J. J. Drake, and S. L. Cully
Astronomy & Astrophysics, 302, 193, 1995.  [CEA publication #717]

   The extreme ultraviolet emission obtained during a 1992 July 14-17
observation of AU Mic has been studied with lines detected with the
short, medium, and long wavelength (SW, MW, LW) spectrometers on the
Extreme Ultraviolet Explorer (EUVE).  The flares were observed during
this period.  The time evolution of the differential emission measure
is presented.  The synthetic spectrum derived from the differential
emission measure is compared with the observed data.  An estimate of
the density and volume of the emitting plasma is obtained using Fe XXI


R. Battle and I. Hawkins
Report to NASA, 1995.  [CEA publication #720]

   We begin this report with a description of the history, goals, and
structure of "Science On-Line -- Earth and Space Science for the
Classroom (SOL)," an Internet-based lesson plan development project.
In the second section, we present the theoretical principles upon
which the project was designed.  In the third section, we present an
overview of the Science On-Line events. In the fourth and fifth
sections, we describe the Internet-based lesson plan development
process.  This includes a discussion of design problems, successes,
and development practices.  In the sixth section, we present a section
on the pilot-testing phase of the lessons.  This section describes the
pilot testing and gives a brief overview of feedback for each of six
lessons generated by the pilot-testing phase.  Implications are
described in the seventh and final section.  We envision that the
Science On-Line (SOL) results will provide valuable guidance for the
design and implementation of similar future programs.


S. Vennes and J.R. Thorstensen
In White Dwarfs, ed. D. Koester and K. Werner (Berlin:
  Springer-Verlag), Proceedings of the 9th European Workshop on White
  Dwarfs, 313-317, 1995. [CEA publication #722; not preprinted]

   We examine the orbital and physical properties of the EUVE sample of
white dwarfs found in binary systems with short orbital periods (~1
d).  These systems, consisting of a hot white dwarf and a main
sequence star, are recent survivors of a common envelope phase
responsible for dramatic momentum losses and orbital shrinkage.  The
white dwarfs in close binaries also constitute a surprisingly large
fraction of the total sample of white dwarfs discovered in the EUVE
all-sky survey.  Most secondary stars are M-dwarfs, with an average
mass of > 0.5 M_solar, and comparisons with some simulated samples of
close binaries suggest that many more systems with very low mass
secondary stars (< 0.3 M_solar) remain to be discovered.


J. Dupuis and S. Vennes
In White Dwarfs, ed. D. Koester and K. Werner (Berlin:
  Springer-Verlag), Proceedings of the 9th European Workshop on White
  Dwarfs, 323-327, 1995. [CEA publication #723; not preprinted]

   We report observations by the Extreme Ultraviolet Explorer (EUVE)
of the hot DA stars Feige 24, G191-B2B, HZ 43, GD 71, and GD 153 which
are among the brightest white dwarfs observed by EUVE.  Spectral
features such as the He I photoionization edge at 504 A and the
autoionization feature at 206 A, as well as the He II photoionization
edge at 228 A are fingerprints of the ISM typically detected in the
EUVE spectra of hot DA.  Effective temperatures both obtained from the
fitting of pure hydrogen and metal-blanketed models are derived along
with the ISM column densities of H I and He I.


R. Napiwotzki, S. Jordan, D. Koester, V. Weidemann, S. Bowyer, and M.
In White Dwarfs, ed. D. Koester and K. Werner (Berlin:
  Springer-Verlag), Proceedings of the 9th European Workshop on White
  Dwarfs, 337, 1995.  [CEA publication #724; not preprinted]

   We present an analysis of FUV and EUV observations of the cool DO
white dwarf HD 149499 B.  It is by far the brightest star (V ~ 11.7)
of this class.  However, it is a secondary in a binary system,
separated from a K0V primary 3 mag brighter in V by only 1.5 arc-sec.
This makes optical observations of the white dwarf nearly impossible.
However, in the FUV/EUV region the flux of the hot white dwarf is
virtually undisturbed by the cool companion.


I. Hawkins and R. Battle
To be presented at the 80th Annual Meeting of the American Education
  Research Association, New York, April 1996.  [CEA publication #725]

   This project investigates methods by which collaborations among
teachers, other professional educators, and scientists can help the
access of scientific data by teachers and students, taking advantage
of a more technologically-driven, research-based model of learning.
This investigation is developing case studies for effective ways of
supporting teachers in the contextually relevant use of Internet
technology in the class room environment.


R. Battle and I. Hawkins
To be presented at the 80th Annual Meeting of the American Education
  Research Association, New York, April 1996.  [CEA publication #726]

   This study investigates effective practices for
educationally-relevant uses of distributed Internet resources made
available by the advent of platform-dependent World Wide Web
resources. This investigation developed case studies of emerging
practices in the context of the creation and pilot testing of
classroom Inter net-based instruction lessons. These case studies will
serve as exemplars of tested Internet-based lesson development
practices for the educational community.


2. EUVE Science Operations News

2.1 Change in Data Recording Strategy -- Orbital Night Only
	by Ronald J. Oliversen, EUVE Associate Project Scientist at GSFC

   On 14 Mar the EUVE Project changed the on-board tape recording
management scheme to record orbital night data only.  This change has
been precipitated by reduced funding for spacecraft operations, the
eight hour on-board tape record capacity, and the eventual
single-shift coverage of the explorer platform flight operations team.
For most programs, this change should have minimal impact on EUVE
science.  The EUVE Project has never had a requirement to deliver
orbital day science data (due to the poorer quality of these data) and
has only delivered orbital night data as the standard GO data product.
For those few programs that have made special requests for orbital day
data in the past, we will not change our data recording strategy to
accommodate those requests.  We regret any problems that this may

2.2 CEA Proposal to "Outsource" EUVE Mission
	by Dr. Roger Malina, EUVE Mission Operations Principal

   It is now NASA policy to carry out outsourcing of routine
spacecraft operations to industry or academia.  After discussion with
NASA officials and the EUVE Users Committee, the University of
California at Berkeley has submitted a proposal to NASA for
outsourcing of EUVE that is responsive to this new NASA strategy. The
proposal addresses concerns raised by the EUVE Users Committee to
ensure that an outsourced EUVE project is fully responsive to the
needs of the user community, and for completion of the EUVE archive
after the end of mission. Additional information on this unsolicited
proposal can be obtained by contacting Roger Malina

   NASA currently plans to terminate EUVE operations in the Fall of
1997.  NASA will be conducting a Senior Review this summer that will
consider extending EUVE operations beyond this date; as we understand
it, unless EUVE is successfully outsourced, extension beyond the Fall
of 1997 is unlikely.

   The EUVE Users Committee will be developing the proposal to NASA to
make the scientific case for extending EUVE operations beyond fall
1997.  New EUVE scientific results over the coming months will be
important factors in convincing NASA to extend the EUVE mission. The
EUVE user community is urged to make the EUVE Users Committee or the
EUVE GO Center aware of new results accepted for publication so that
these can be highlighted in the EUVE extended mission proposal.

2.3 Upcoming Observation of Comet 1996 B2 (Hyakutake)
	by Dave Meriwether, ISO Observation Support Team Leader

   The long-period comet C/1996 B2 (Hyakutake; P = 18,000 years) will
make its closest approach to Earth this month, coming to within ~10
million miles -- a mere stone's throw in astronomical terms.  EUVE
will observe C/1996 B2 for four days in late Mar.  At that time the
motion of C/1996 B2 relative to EUVE will be such the comet will be
moving across the satellite's field of view at a speed comparable to
that of the Moon.  To compensate for this rapid motion, EUVE will need
constant pointing adjustments to properly track C/1996 B2, which makes
this observation the most difficult one yet made with EUVE.  However,
it is expected that the science return will be worth the effort, and
will reveal an unprecedented amount of information on the nature and
behavior of comets.

2.4 Public Data Release for 1 Apr 1996
        by Dr. Nahide Craig, ISO User Support Scientist

   The table below lists the GO observations that become public on 1
Apr 1996.  For each entry is given the target name, the approximate
exposure time in ksec, the GMT start and end date(s) for the
observation, the spectral type of the target, and the data
identification code.  All public data sets can be ordered from the
archive via WWW and electronic or postal mail (see addresses below).
Please be sure to include in your order the DataID(s) of interest.
Processed data sets are shipped on 8mm tape (or, if requested, on
CD-ROM) via postal mail.

   The data rights policy for GO observations states that GOs have
proprietary rights to the data for one year from the date (s)he
receives it.  It is often the case that long observations are broken
up over many months; e.g., an observation approved for 60 ksec may
actually be observed for 10 ksec one month, 20 ksec the next and 30
ksec three months later.  In such cases the one-year proprietary
period begins after the GO is sent the final piece of the completed

      Target        ~Exp     Observation Date(s)     SpT      DataID
       Name        (ksec)    Start           End

     Data Sets Available 1 Apr 1996:

      CN Leo         100     24 Jan - 27 Jan 1995    M        go284
      CN Leo          35     27 Jan - 29 Jan 1995    M        go285
      EK UMa          46     14 Dec - 15 Jan 1994    CV       go286
      EUVE J0425-572   7     19 Jan - 19 Jan 1995    NOID     go287
      Feige 24        29     22 Oct - 23 Jan 1994    WD       go288
      Vela           139     4  Feb -  9 Jan 1994    SN       go168
      Vela            43     18 Mar - 20 Jan 1994    SN       go289
      Vela            73     25 Nov - 27 Jan 1994    SN       go290


2.5 On-Line Access to EUVE

   Listed below are the various methods for on-line access to EUVE:

 o CEA World Wide Web (WWW)
   telnet 200 (for those without a WWW browser)

 o anonymous FTP
	Name:  anonymous
	Password:  type_your_full_e-mail_address

 o anonymous gopher

 o EUVE Electronic Newsletters
     Past issues -- available via the CEA WWW site
     Subscriptions -- mail ("subscribe
     Post message to all subscribers:  mail

 o GI Program
     Are you interested in finding out about or using EUVE data?  Do
     you need help in understanding EUVE data sets?  Do you need help
     in using the available EUVE data analysis software tools?  If you
     answer "yes" to any of the above, the Guest Investigator (GI)
     Program at CEA can help YOU!  For more information see the CEA
     WWW site or contact the Archive (

 o Public RAP
     The Public Right Angle Program (RAP) is an easy method for
     researchers to propose for long-exposure EUVE imaging data.  For
     more information on the Public RAP and the simple proposal
     process see the CEA WWW site or contact the EGO Center
     (  Mail all proposals to

 o Contact information for the EUVE Science Archive or GO Center:

			Center for EUV Astrophysics
			2150 Kittredge St.
			Berkeley, CA  94720-5030

		Archive 			EGO Center
	510-642-3032 (voice)    	510-643-8727 (voice)
	510-643-5660 (fax)      	510-643-5660 (fax)

  The EUVE Electronic Newsletter is issued by the Center for Extreme
  Ultraviolet Astrophysics, University of California, Berkeley, CA
  94720, USA.  The opinions expressed are those of the authors.  EUVE
  Principal Investigators and Newsletter Publishers: Dr. R.F. Malina
  and Professor S. Bowyer.  ISO Manager and Newsletter Editor: B.A.
  Stroozas.  Funded by NASA contract NAS5-29298.  Send newsletter
  correspondence to

  The EUVE project is managed by NASA's GSFC: Paul Pashby, GSFC
  Project Manager; Dr. Yoji Kondo, Project Scientist; Dr. Ronald
  Oliversen, Deputy Project Scientist; Mr. Kevin Hartnett, Project
  Operations Director.  NASA HQ: Dr. G. Riegler, Program Manager.
  Information on the EUVE GO Program is available from Dr. Y. Kondo,
  Mail Code 684, GSFC, Greenbelt, MD 20771 at (301) 286-6247 or e-mail

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