Supersoft X-ray sources as supernova Type 1 candidates / progenitors
(vsnet-chat 55)
Berto Monard wrote:
> surely, most
> overweight WDs will go bang at their time! Where else are the
> progenitors of the supernovae Type 1 then, iow how do WDs
> increase their mass if not in close binaries?
This point has been argued by many authors. Not all accreting white
dwarfs are expected to be observed as novae or typical CVs. Some may be
found in symbiotic binaries, others may reside in the recently discovered
class of binaries called supersoft X-ray sources (SSS). The latter class,
named after its peculiar characteristics emitting most of its energy in
soft X-ray and extreme UV regions, is claimed to have rapidly accreting
white dwarfs with steadily burning surfaces. Quite fortunate (?) for
southerners, most of known SSS's reside in the LMC and the SMC; there is
only one in the northern hemisphere -- the VSOLJ has already started regular
monitoring of this star (RX J0019.8+2156) in order to detect a possible
supernova explosion -- what an immortal mind of pursuit!
There is another way to make SNe Ia, by merging binary white dwarfs.
Hope supernovae professionals probably have a lecture further...
By the way, what about Monard's initial query whether supernova explosions
(or collapses?) could be triggered by nova explosions?
Regards,
Taichi Kato
(vsnet-chat 57)
Hi ,
T Kato mentioned the supersoft X-ray sources (SSS) as possible
S/N progenitors, a number of them residing in the Magellanic
Clouds.
Please can someone forward names and addresses (coordinates)
of such systems, so some hopefuls in the South could try their
luck! What B and V magnitudes do they normally evolve around?
Surely, they are out of reach of a 5" telescope.
Further questions: do these SSS somehow relate to Novalikes,
which also accrete fast and what about these Nls as potential S/N
candidates?
Regards,
Berto Monard,
Pretoria
Draco C-1 (Munari)
(vsnet-chat 60)
To the best of my knowledge, there are several SSXS (Super Soft X-ray Sources)
in the northern emisphere, not only that one mentioned by T.Kato.
One that could be be an excellent target for CCD-equipped amateurs is
Draco C-1, a symbiotic star in the Draco dwarf galaxy. It shines at
V=17 and I=15. The donor star to the accreting white dwarf is a
carbon bright giant, at the very tip of the AGB (to have a carbon
giant in a dwarf galaxy means that star formation was still active not much
long ago). Is the Carbon star in Draco C-1 pulsating ? If yes, the
mass transfert to the WD companion would be larger. And if yes, what is
the pulsating period ? The carbon stars in the Draco dwarfs seems unsually
blue, and this could trigger quite short pulsation periods (lass than 100
days).
Regards
Ulisse Munari
Padova-Asiago Astronomical Observatories
(vsnet-chat 61)
Berto Monard wrote:
> a number of them residing in the Magellanic Clouds.
> Please can someone forward names and addresses (coordinates)
> of such systems, so some hopefuls in the South could try their
> luck! What B and V magnitudes do they normally evolve around?
> Surely, they are out of reach of a 5" telescope.
>
> Further questions: do these SSS somehow relate to Novalikes,
> which also accrete fast and what about these Nls as potential S/N
> candidates?
Acoording to Marina Orio's table in "Cataclysmic Variables" p.429 (1995,
Kluwer Academic Publishers) and some other literatures, following Magellanic
and Galactic SSS's are listed.
Unfortunately this list contains neither precise coodinates, nor Draco
C-1, though the object is rather familiar among northerners (as an extra-
galactic symbiotic star reachable by amateur telescopes). Is there any
catalog of SSS's like Ritter's or Downes & Shara's in CVs?
Regards,
Taichi Kato
LMC sources
-----------
CAL 83 V~17.3 Porb=1.04d, persistent source
CAL 87 V~20.1 Porb=10.6h, persistent source, eclipsing
(Some may remember this name as a blackhole binary
candidate. Recently imaged by HST.)
RX J0513.9-6951 B~17 Porb=0.76d (recent determination), recurrent source
high/low states
RX J0527.8-6954 ?
RX J0550-72 ? variable
RX J0537-7034 ? variable
RX J0439-68 ? constant
SMC sources
-----------
N 67 planetary nebula
1E 0035.4-7230 B~20 Porb=0.172d variable
RX J0058-71 ?
RX J0112-72 ?
SMC 3 symbiotic star
Galactic sources
----------------
GQ Mus nova, Porb=1.42h, "ON" for 9.5 years
RR Tel symbiotic nova
PW Vul? nova, "ON" for few years
QU Vel? nova, "ON" for few years
V1974 Cyg nova, "ON" for 1 year
RX J0019.8+2156 B~12 Porb=15.8h, variable, high/low states
RX J0925.7-4758 B~17 Porb=3.4d, persistent source
H1504+65 B=16.24, PG1159 star (pulsating dO star)
RX J2117.1+3412 V~13.2, PG1159 star
AG Dra symbiotic star Porb=554d
(vsnet-chat 62)
Subject : SSXS Catalog
As I know of, an up-to-date list of SSXS is given by J. Greiner (Catalog
of Luminous Supersoft X-Ray Sources, P285 of Supersoft X-Ray Sources,
Ed. J. Greiner, 1996, Springer). Is there any newer list ?
Also, Mario Livio pointed out to me that the above mentioned book discussed
about a possibility of SSXS be the SN Ia progenitors (Part V of the volume,
P183 - P222).
Cheers,
-Kaz
|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
| Kaz Sekiguchi | Phone +81 422 34 3710 |
| Subaru 8.3-m Telescope Project Office | Fax +81 422 34 3608 |
| National Astronomical Observatory of Japan | Email kaz@optik.mtk.nao.ac.jp |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(vsnet-chat 63)
Kaz Sekiguchi wrote:
> As I know of, an up-to-date list of SSXS is given by J. Greiner (Catalog
> of Luminous Supersoft X-Ray Sources, P285 of Supersoft X-Ray Sources,
> Ed. J. Greiner, 1996, Springer). Is there any newer list ?
Thank you very much for the information. I have once looked (but not
read ;-) this book but overlooked the catalog. Coordinates and magnitudes
added:
LMC sources
-----------
CAL 83 05 43 33.5 -68 22 23 V=16.2-17.3 SSS
CAL 87 05 46 52.3 -71 08 38 V=18.9 SSS
RX J0513.9-6951 05 13 50.8 -69 51 47 V=16.7 SSS = HV 5682
RX J0527.8-6954 05 27 49.9 -69 54 09 unidentified
RX J0550.0-7151 05 50 00.2 -71 52 09 unidentified
RX J0537.7-7034 05 37 43.0 -70 34 15 unidentified
RX J0439.8-6809 04 39 49.6 -68 09 02 V=21.7 SSS
SMC sources
-----------
N 67 00 58 37.0 -71 35 48 V=16.7 PN = 1E 0056.8-7154
1E 0035.4-7230 00 37 19.8 -72 14 13 V=20.2 SSS
RX J0058.6-7146 00 58 35.8 -71 46 02 unidentified
RX J0112-72
SMC 3 00 48 20.8 -73 31 53 V=15.5 Sy = RX J0048.4-7332
Galactic sources
----------------
GQ Mus 11 52 02.5 -67 12 24 V=7-21 N
RR Tel 20 04 18.5 -55 43 34 V=7-14 Sy
PW Vul?
QU Vel?
V1974 Cyg 20 30 31.2 -52 37 53 V=4.5-21 N
RX J0019.8+2156 00 19 50.0 +21 56 54 V=12.2 SSS
RX J0925.7-4758 09 25 46.2 -47 58 17 V=17.2 SSS
H1504+65 (omitted)
1E 1339.8+2837 13 42 09.8 +28 22 45 unidentified
RX J2117.1+3412 (omitted)
AG Dra 16 01 40.9 +66 48 10 V=8-9.8 Sy
(type: SSS = CAL 83-like supersoft source, PN = planetary nebula,
Sy = symbiotic system, N = nova)
In this book, Draco C-1 is listed in the table of "symbiotic stars
detected on pointed PSPC observations". Other detections include
EG And, SMC 3, Ln 358, RX Pup, AG Dra, GX 1+4, Hen 1591, CH Cyg,
HM Sge, V1016 Cyg, RR Tel, PU Vul, CD-43.14304, AG Peg and R Aqr.
Non-detections include SMC 2, RAW 1691, BE 191, N 67, Sanduleak's star,
MWC 560, He 2-38, RW Hya, Ap 1-8, H 2-38, Ap 1-9, AS 281, MWC 960
and Z And.
Regards,
Taichi Kato
Coordinates for LMC X-Ray sources (Morel)
(vsnet-chat 71)
Dear Readers,
In 1996 I received from Dr. Paul Schmidtke, Arizona State University,
a number of reprints reporting the results of his work on LMC/SMC
X-ray sources, especially Supersoft Sources (SSS). Study of these
sources is a highly specialized area, involving firstly use of data
form X-ray detecting satellites such as ROSAT. The identification of
optical counterparts is a somewhat painstaking process, using large
telescopes, as the optical ids., are generally faint, at the mag.
19-20 level. However, a couple of the LMC SSS's have been studied
in some detail at optical wavelengths, such as CAL 87, which is an
eclipsing binary. It shows short duration, shallow X-Ray eclipses
which coincide in phase with the primary optical minimum. A paper
appears in Pub. Ast. Soc. of the Pacific, 105, 863-866, 1993 August.
A finder chart is given, but no coordinates. The position is
(1950) 5h47m27.0s -71 10'11". This star is included in the list of
known LMC variables in vol. 5 of the GCVS, as star V4382 (page 69).
Not all X-ray sources in the direction of the Magellanic clouds are
Cloud members. Some are local foreground stars, while some are even
background objects (AGNs - Active Galaxy Nuclei).
Another reprint summarizes LMC SSS's as follows:
Source: reprint of paper "Supersoft X-ray Sources in the LMC", pp439-444 in
'Compact Stars in Binaries' (1996, J. van Paradijs et al eds.).
A very useful paper providing positions and finder charts for Magellanic
Cloud X-ray sources appears in Publ. A.S.P. for January 1997.
Cheers,
Mati Morel
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++
MOREL ASTROGRAPHICS
Stellar Data & Information Centre
c/o M. Morel
6 Blakewell Road,
Thornton NSW 2322
AUSTRALIA
Tel. /fax : 61 49 662078 E-mail: morel @ozemail.com.au
++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
- NEWCASTLE NSW: CELEBRATING ITS BICENTENARY 1797-1997.
Draco C-1 and the SSXS (Munari)
(vsnet-chat 81)
A few additional words about Draco C-1 for those interested to have a look
at it:
RA (2000.) = 17 19 57.5
DEC = +57 50 05
An I-band excellent finding chart is published by Aaronson et al. (1982)
ApJ 254, 507. Inside 4 arcmin from C-1 there are also C-2 and C-3, the only
other known carbon stars is the Draco dwarf galaxy (satellite of our own
Galaxy). They all shine around V=17 and I=15 mag.
The ROSAT observations on the Super-Soft X-ray Source nature of
Draco C-1 have been discussed at the June 1996 Colloquium on Symbiotic
Stars (the proceedings due to appear in press in these weeks).
The ultraviolet properties as inferred from IUE observations have been
discussed by Munari & Buson (1994, Astron.Astrophys. 287, 87).
The WD in C-1 is so hot and luminous that no better explanation exists
that it is stably burning the accreted material from the carbon giant
companion. A bright outburst (no one so far recorded) could onset any
moment. From application of standard mass-luminosity relations
it appears that the WD in Draco C-1 is closing on the Chadrasekhar mass,
opening bright prospects for a SN Ia display.
Because the distance module and reddening of the Draco galaxy is
m - M = 19.6 E(B-V)= 0.03 mag
a SN Ia exploding there could rival in apparent magnitude with Vega !
A last word about finding charts of ROSAT sources. Apart from those in
the Grainer et al. (ed) proceedings, finding charts for 384 and 169
respectively extreme ultraviolet sources (EUV) observed by ROSAT
can be found in:
Shara et al. (1993) PASP 105, 387
Mason et al. (1995) MNRAS 274, 1194
Regards
Ulisse Munari
Padova-Asiago Astronomical Observatories
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