The IUE obtained ultraviolet data on novae in outburst. The characteristics of every one of the outbursts are different. Optical and infrared data on many of the same novae were also obtained. Three members of the carbon-oxygen class of novae are presented

Ferland, Gary

Gehrz, Robert D.

Kenyon, Scott

Ney, Edward P.

Sonneborn, G.

Sparks, Warren M.

Starrfield, S.

Stryker, L. L.

Wagner, R. M.

Williams, R. E.

English

NASA Technical Reports Server

N89-10708 159
_Rl_l_')l_rO PAGE BLANK NOT FILI_/P_J)
OBSERVATIONS OF CLASSICAL NOVAE IN OUTBURST
S. Starrfleld and L. L Stryker
Department of Physics, Arizona State University
G. Sonneborn /
IUE Observatory, Goddard Space Flight Center _/"
Warren M. Sparks
Applied Theoretical Physics Division
Los Alamos National Laboratory
Gary Ferland and R. M. Wagner
Department of Astronomy, Ohio State University
R. E. Williams
Cerro Tololo Interamerican Observatory
Robert D. Gehrz and Edward P. Ney
Department of Astronomy, University of Minnesota
Scott Kenyon
Center for Astrophysics, Harvard University
R. Wade
Steward Observatory, University of Arizona
James W. Truran
Department of Astronomy, University of Illinois
C.-C. Wu
Space Telescope Science Institute
ABSTRACT
Over the past 10 years the IUE Satellite has
obtained ultraviolet data on a number of novae in
outburst and the characteristics of every one of the
outbursts have been different. In addition, our group
has also obtained optical and infrared data on many of
the same novae. In this paper we present the data on
three members of the carbon-oxygen class of novae.
1. Introduction
We are continuing to obtain data on novae in outburst
and the novae that are still bright enough to study
with the IUE Satellite are Nova Vui 1984 #2, Nova And
1986, Nova Vul 1987, and Nova LMC 1988. Nova Vul
1984 #2 is a slow oxygen-neon-magnesium nova, Nova
And is a moderately fast carbon-oxygen nova, and
Nova Vul 1987 had a period of about a month with
nearly constant light and then started a slow decline
but it exhibited a very deep transition phase when it
formed dust.
The ultraviolet observations of novae done with the
IUE Satellite have proved to be of extreme importance
in understanding the cause and evolution of the
outburst. As summarized in reviews by Starrfield and
Snijders (1987), Starrfieid (1987), and Starrfield
(1988), the ultraviolet spectra have shown that there
are two classes of novae, have shown that there are at
least two classes of recurrent novae, and have allowed
much more acurrate determinations of elemental
abundances. The importance of the IUE data is that
there are spectral lines in the 1200A to 3300A wave-
length range that come from elements which do not
have analyzable (or any) lines in the optical. These
lines can be used to determine elemental abundances,
expansion velocities, and the amount of mass ejected.
Many of these lines are the commonly observed and
well understood medium ionization UV resonance and
intercombination lines observed in most emission line
objects. However, their time-dependant behavior in
novae can be used to constrain the abundances that
are determined for the ejected material. A table of
such lines and the time variations of their fluxes for
one nova can be found in Williams, et al. (1985).
Because of IUE data, we have recently been able to
identify a new class of novae (Starrfield, Sparks, and
Truran 1986). Finally, continuum flux distributions can
be used to determine temperatures of the white dwarf
and/or mass transfer rates onto the white dwarf.
In companion papers in this meeting we discuss the
ultraviolet observations of Nova Vul 1984 #2, a slow
oxygen-neon-magnesium nova, the ultraviolet observa-
tions of Nova V394 CrA a very fast recurrent nova;
and two recent novae: Nova Vul 1987 and the 1988
nova in the LMC. In this paper we present and
discuss the ultraviolet data on 3 of the other novae
that we have observed in the last two years. These
are Nova Vul 1984 #1, Nova And 1986; and Nova Her
1987. They are all apparently carbon-oxygen novae
with differing ejection velocities and rates of decline.
2. Observations
Nova PW Vul 1984 #1. The first slow nova to be
studied by IUE was PW Vul (1984 No. 1). We were
able to obtain spectra for this nova from maximum
light in August 1984 until late in 1986. Optical and IR
data for this nova were presented by Kenyon and Wade
(1986) who determined a distance of -1.2 kpc. They
also report He/H of "0.13 (by number) and that oxygen
was enhanced in the ejecta. They did not find a neon
enhancement. The IUE data are currently being
A Decade of UV Astronomy with IUE, Proc Celebratory Symposium, GSFC, Greenbelt, USA, 12-15 April 1988, ESA SP-281, Vol. 1 (June 1988)
https://ntrs.nasa.gov/search.jsp?R=19890001337 2020-03-20T05:58:15+00:00Z
160 S STARRF1ELD ET AL
reduced and analyzed. Spectra taken on May 24, 1985
(SWP 26244 and LWP 6264) and October 29, 1985 (SWP
26997) are presented in Figures 1 and 2. The LWP
spectrum taken in October 1985 was underexposed.
Note that from May to October the peak SWP fluxes
fell by almost a factor of 10. The strongest lines are
from CIV, OIV, NIV, NIII, CIII, and NV. This is
obviously a carbon oxygen outburst since none of the
strong neon or magnesium lines, found in Nova Vul
1984 #2 (Starrfield et al. 1988; these proceedings), are
present in these spectra. The nitrogen came from
carbon and oxygen by means of hot hydrogen burning
in carbo-oxygen enriched material.
Nova Andromeda 1986 was discovered in outburst in
early December 1986 and we begain obtaining spectra
almost immediately. We have been able to follow it
through its outburst and are also obtaining optical
data. Spectra taken at maximum are shown in a paper
by Stryker et al. (1988; these proceedings). In Figures
3 and 4 we display SWP and LWP spectra obtained on
July 12, 1987 and a SWP spectrum obtained on
November 15, 1987. This last spectrum took 105
minutes and we were unable to obtain an LWP
spectrum. This is a moderately fast nova; the peak
flux of CIV 1549A fell by less than a factor of two in
the 4 month interval. The spectral features shown in
these two spectra are quite similar to those of Nova
Vul 1984 #1 and it must also be a carbon-oxygen nova.
Acknowledgements
This study would not have been possible without the
response of the IUE Observatory to the request for
continuing observations of novae in outburst and we
are grateful for their continued support of this study.
The data were reduced with the facilities of the RDAF
at the University of Colorado, which are supported by
NASA Grant NAS5-28731, and the assistance of T.
Armitage. We also acknowledge partial support for this
research from NASA, NSF, and the DOE through grants
to our various institutions.
References
Kenyon, S. J., and Wade, R. 1986, P.A_S.P, 98, 935.
Starrfield, S. 1987, in New lnsithts in Astrophysics:
Eight Years of Ultraviolet Astronomy wilh IUE,
ed. E. Rolfe, ESA press, (Nordwijk) SP-263, p.
239.
Starrfield, S. 1988, in Classical Nova, ed. N. Evans, and
M. Bode, (New York: Wiley) in press.
Starrfield, S. and Snijders, M. A. J. 1987, in
Accomplishments of the IUE Satellite, ed. Y.
Kondo (Dordrecht: Reidel), p. 377.
Starrfield, S., Sparks, W.M., and Truran, J.W. 1986, Ao.
J. Lett., 303, L5.
Williams, R.E., Ney, E.P., Sparks, W.M., Starrfield, S.,
and Truran, J.W. 1985, M.N.R.A.SL, 212, 753.
Nova Hercules 1987 was discovered in outburst early in
1987 and we decided not to observe it since we were
already following two other novae (Nova Vul 1984 #2
and Nova And 1986) and the European team was
observing Nova Cen 1986. In April 1987 Gehrz and
Jones (IAU Announcement Card #4371) found that it
had formed dust with a temperature of about 1000K.
In addition, they noted that there was evidence for
strong [Ne II] emission at 12.8#m. Then in May 1987,
Andrillat (IAU Announcement Card # 4388) reported
that she had found it to be in the nebular stage with
strong [O III] and NIII lines present in the spectrum.
In addition, she also reported that [Ne III] 3688A and
[NeV] 3346A and 3426A were present in the spectrum.
These two reports suggested that this could be another
oxygen-neon-magnesium nova and given this possibility,
we obtained an SWP and LWP spectrum on June 11,
1987. These spectra are shown in Figure 5. As in the
two other novae discussed in this paper, the spectra
show mostly lines from carbon, oxygen, and nitrogen
ions and it appears to be a carbon-oxygen nova. The
strongest lines are from C IV, C III, N III, N V, CII,
O IV, and O III. Given this result, we obtained no
further spectra of this nova.
3. Summary
We have obtained ultraviolet spectra for three novae
that appear to have ejected material rich in oxygen,
nitrogen, and carbon. We will be unable to determine
if these elements are actually enhanced in the ejecta
until we have finished our nebular analysis. This work
is in progress.
T
1200 1300 1400 ISO0 1600 1700 1800 1900
WAVELENGTH (_)
Figure la. This SWP spectrum was a 20 minute
exposure of Nova Vul 1984 #1 obtained on May 24,
1985. The strong lines are from carbon, nitrogen, and
oxvRen.
Figure lb. This 10 minute LWP spectrum of Nova Vul
1984 #1 was obtained on May 24, 1985. Note that even
after nearly a year in outburst there is still a
continuum present.
CLASSICALNOVAEINOUTBURST 161
7
o
o FT_T_T_-_-1-r-_-I-'_T _-_-__-l-w,-_ _-i-_-_q
'_ [_
1200 I300 1400 1500 1600 1700 1000 1000
WAVEI ENCTI] {_.)
Figure 2. This 15 minute SWP spectrum of Nova Vul
1984 #1 was obtained on October 29, 1985. The peak
fluxes have declined considerably.
7
'E
?
E
2
-_-w,-r-l-_-w_-_F_T_--_T ,_-T-r,-,-----r_-w-l-_-T_
LL ,_,_I___A_-__,__-L__L._u
1000 1300 1400 1500 1000 1700 I_00 I900
WAVELLNCTll (_)
Figure 4a. This 30 minute SWP spectrum was obtained
of Nova And 1986 on July 12, 1987. Note that the
strong lines are from carbon, nitrogen, and oxygen
ions.
?
-_L
f7
ok
LI,,,,I_I .... I .... I .... I .... [ .... _ , , ,al
1200 I t00 1400 1000 tB00 1700 1600 1900
'aAVELENGTtI (A)
:<
T
'o
o
4
' I ' ' -
0000 2400 2{300 Ea00 3000 3200
WAVELENGTH (,[)
Figure 3a. This 30 minute SWP spectrum of Nova Her
1987 was obtained on June II, 1987. There are
apparently no lines of neon or magnesium present.
Figure 4b. This 45 minute LWP spectrum of Nova And
1986 was obtained on July 12, 1987.
/
?
o
7
o
°_l i i i I i i i I _ i i I , , i I i , , I i , , 1-
2200 2400 2600 2800 3000 3200 3400
WAVELENGTH (_.)
Figure 3b. This 65 minute LWP spectrum was obtained
of Nova Her 1987 on June I1, 1987. Not only is there
a red continuum present but the neon lines seen by
Andrillat in the optical are visible at the red end of
the spectrum.
'I"_,_M _7",','_;r?',_,, , , .... , .... W,-_,,
i _
1200 1300 1400 1500 1600 1700 1800 1900
WAVELENGTH (_)
Figure 5. This 105 minute SWP spectrum of Nova And
1986 was obtained on November 15, 1987 nearly a year
after maximum.


Observations of classical novae in outburst

Observations of classical novae in outburst

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