The IUE obtained ultraviolet spectra of a nova in an external galaxy. The spectral features do not seem unusual for a nova at maximum but it is hoped to be able to follow it for a long enough time to be able to study the high ionization lines that appear when the density drops to lower values (the nebular stage). A high dispersion spectrum was also obtained to assist in the line identification and to study the line of sight to the LMC 1 deg of arc away from SN 1987A

Ferland, Gary

Gallagher, J. S.

Sion, E. M.

Sonneborn, G.

Sparks, Warren M.

Starrfield, S.

Stryker, L. L.

Wade, R.

Wagner, R. M.

Williams, R. E.

English

NASA Technical Reports Server

N89 - 107 1 2
PRECEDING PAGE BLANg NOT rlZM'ED
ULTRAVIOLET OBSERVATIONS OF LMC NOVA 1988
S. Starrfield and L. L Stryker
Department of Physics, Ai'izona State University
G. Sonneborn
IUE Observatory, Goddard Space Flight Center _
Warren M. Sparks
Applied Theoretical Physics Division
Los Alamos National Laboratory
E. M. Sion
Department of Astronomy, Villanova University
R. M. Wagner and Gary Ferland
Department of Astronomy, Ohio State University
J. S. Gallagher
Lowell Observatory
R. Wade
Steward Observatory, University of Arizona
R. E. Williams and S. Heathcote
Cerro Tololo Interamerican Observatory
Robert D. Gehrz and Edward P. Ney
Department of Astronomy, University of Minnesota
Scott Kenyon
Center for Astrophysics, Harvard University
G. Shaviv
Department of Physics, The Technion
Rainer Wehrse and P. Hauschildt
Institute of Theoretical Astronomy
University of Heidelberg
James W. Truran
Department of Astronomy, University of Illinois
C. - C. Wu
Space Telescope Science Institute
ABSTRACT
This currently bright novae was first detected in
outburst on March 21, 1988. Its discovery has given
us the opportunity of studying the first extragalactic
nova in the ultraviolet and we have, therefore,
obtained a number of LWP and SWP spectra when it
was at maximum. We have also obtained a high
dispersion LWP spectrum in order to study the ISM in
the Large Magellanic Cloud on a slightly different line-
of-sight from that analyzed using SN 1987A.
present) and it is probable, anyway, that they would
have been too faint to study when they reached this
phase.
We also note that Ciardullo etal. (1987) found that the
distribution of bulge novae in M31 follows the light
from the bulge and only a few novae appear to come
from a disk distribution. However, it seems most
likely that most of the novae in the solar neighborhood
come from a disk population and we are not detecting
the bulge novae in our own galaxy.
1. Introduction
Except for a small number of investigations, the
studies of novae in external galaxies have been
primarily limited to studies of their distribution and
light curves. The major studies of the distribution of
novae have been done for M31 (Arp 1956; Rosino 1973;
Ciardullo et al. 1987). The most recent spectroscopic
analyses of novae in M31 have been done by Ciardullo,
Ford, and Jaeoby (1983) and Cowley and Starrfield
(1987).
The spectral features seen in the spectra of the four
novae studied by Ciardullo, Ford, and Jacoby (1983)
and the one slow nova studied by Cowley and
Starrfield (1987) appear quite normal. However, in
neither study were the novae followed through to the
nebular stage of their evolution (when the density of
the expanding shell has fallen to where a large number
of forbidden lines from highly ionized species are
The theoretical studies of the nova outburst have
shown that the observed properties of the explosion
depend upon a variety of factors such as white dwarf
mass, white dwarf luminosity, mass accretion rate, and
the chemical composition of the mixed (accreted
material plus core material) envelope (see Starrfieid
1987; Starrfield and Sparks 1987; and Shaviv and
Starrfield 1987 for recent reviews). While there is no
theoretical reason to expect to find fundamental
differences between nova outbursts that occur in
different stellar populations, it is still important to
study novae in as many different environments as
possible and either confirm or deny the theoretical
investigations.
While the nearest large galaxy to our own is the I_-qC
and it is known to exhibit nova outbursts with a
reasonable frequency (Graham 1987; private communica-
tion), there have been no detailed optical or ultraviolet
studies of novae in this galaxy. Therefore, when a
bright nova was recently discovered in the LMC, we
A Decade of UV Astronomy wtth IUE, Proc. Celebratory Symposium, GSFC, Greenbelt, USA, 12-15 Aprtl 1988, ESA SP-281, Vol. 1 (June 1988)
https://ntrs.nasa.gov/search.jsp?R=19890001341 2020-03-20T06:08:39+00:00Z
176 S STARRFIELD ET AL
:<
7
"E
140O 1500 1800 1700 1800 1900 8000
WAVELENGTH (_)
2
o
2200 2400 2600 280Q 3000 3200
WAV_'I FNCTII (*_)
Figure la. This 80 minute SWP spectrum was obtained
on March 25, 1988. It is a typical spectrum for a nova
near maximum.
Figure lb. This 30 minute LWP spectrum was also
obtained on March 25, 1988. Note the very deep P-
Cygni profile for Mg II 2800/k. The deep depression
at 3055A is a camera artifact.
:<
*o
1400 1500 1600 I ?OO 1800 1800 20O0
WAVELENG fH (.&)
7 2
d 2
&
a
2200 2400 2600 2800 3000 3200
WAVELENGTH (_)
Figure 2a. This is a 160 minute SWP spectrum obtained
on March 30, 1988. There are obvious changes over
the five day interval.
Figure 2b. This is a 15 minute LWP spectrum obtained
on March 30, 1988. The flux scaling between this
spectrum and Figure lb are identical in order to
emphasize the real changes that have occurred in the
spectrum over the 5 day interval.
UVOBSERVATIONSOFTHELMCNOVA1988 177
decidedto observe it both optically and with the IUE
satellite. In addition, this nova turned out to be
bright enough, in the wavelength range of the LWP
camera, to enable us to obtain a high dispersion
spectrogram by combining USI and Vilspa shifts. Aside
from the basic interest in a high dispersion study of
novae (Sion et al. 1986), this image will allow us to
sample the ISM in the LMC on a slightly different line
of sight than was analyzed for SNI987A. It might be
possible to determine which, if any, of the species
found in the SNI987A analysis (Dupree et al. 1987)
actually came from the circumstellar material surround-
ing the progenitor and not the general ISM.
2. Observations
Acknowledgements
This study would not have been possible without the
rapid response of the IUE Observatory to our requests
for Target-of-Opportunity observations of novae and
we are grateful to the IUE observatory for their
continued support of nova observations. The data were
reduced with the facilities of the RDAF at the
University of Colorado which are supported by NASA
Grant NAS5-28731 and T. Armitage's help is gratefully
acknowledged. We also acknowledge partial support for
this research from NASA, NSF, and the DOE through
grants to our various institutions.
This nova was discovered by Garradd on March 21.484
1988 UT (IAU Announcement Card #4568). A precise
position of a = 5h36m01.92 s and 6 - -70 ° 23'15.2"
(1950.0) was provided by McNaught (IAU Announcement
Card #4569). We began obtaining optical spectra at
the 1.5-m telescope at the Cerro Tololo Interamerican
Observatory and obtained IUE SWP and LWP spectra on
March 25, 1988. We were able to obtain more spectra
over the next few days and a high dispersion LWP
spectrum was obtained on March 30, 1988. These
spectra are now undergoing analysis. In this brief
report we show only the two best of the SWP and LWP
spectra as Figures la and lb and 2a and 2b. The date
and exposure times are given in the figure captions.
Completely unlike the ultraviolet behavior of Nova Vul
87 (Starrfield et al. 1988; these proceedings), this nova
still appears to be getting brighter between the first
and last of the spectra. In addition, Mg I1 2800A is
becoming stronger with time. We were unable to
extract and display the high dispersion spectrum before
this meeting. If we are able, we shall present plots of
that spectrum during the meeting.
We have recently begun a project to perform spectral
syntheses of the early spectra of novae (see Stryker et
al. 1988; these proceedings) and these spectra will be
among the first that we analyze.
References
Arp, H. C. 1956, A.J., 61,15.
Ciardullo, R., Ford, H. C., Neill, J. D., Jacoby, G. H.,
and Shafter, A. W. 1987, Ao.J., .
Ciardullo, R., Ford, H. C., and Jacoby, G. H. 1983, Ao.
J., 272, 92.
Cowley, A. P., and Starrfield, S. 1987, A.J., 99, 854.
Dupree, A.K., Kirshner, R. P., Nassiopoulos, G. E.,
Raymond, J. C., and Sonneborn, G. 1987, ADJ.,
320, 597.
Rosino, L. 1973, Astr. At). Sut)t)., 9, 347.
Shaviv, G. and Starrfield, S. 1987, in Proceedin2s of
the Second Conference on Faint Blue Stars. ed. A.
G. D. Philip, D. S. Hayes, and J. Liebert (Schen-
ectady: L. Davis), 427.
Sion, E. M., Starrfield, S., Van Steenberg, M. E.,
Sparks, W. M., Truran, J. W., and Williams, R. E.
1986, A.J., 92, 1145.
Starrfield, S. 1987, in New Insights in Astrot)hy_icg
Eight Years of Ultraviolet Asl;ronomv with IUE,
ed. E. Rolfe, ESA press, (Nordwijk) SP-263, p.
239.
Starrfield, S., and Sparks, W.M. 1987, in Cataclysmic
Variables. Recent Multifreouencv Observations _lnfl
Theoretical Developments, ed. H. Drechsel, Y.
Kondo, and J. Rahe, (Dordrecht: Reidel), p. 379.
3. Summary
We have obtained the first ultraviolet spectra of a
nova in an external galaxy. The spectral features that
are seen do not seem unusual for a nova at maximum
(see Stryker et al. 1988; these proceedings) but we
hope to be able to follow it for a long enough time to
be able to study the high ionization lines that appear
when the density drops to lower values (the nebular
stage). We have also obtained a high dispersion
spectrum and will use it to assist in the line ident-
ification and to study the line of sight to the LMC
about one degree of arc away from SNI987A.


Ultraviolet observations of LMC nova 1988

Ultraviolet observations of LMC nova 1988

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