V475 Sct = Nova Sct 2003


Dear Colleagues,

I have personally received a notification of the likely nova discovery in Scutum via H. Yamaoka. Although I have been asked not to relay the discovery alert to the public, I relay the following information by my own judgement of the potentially high astronomical significance. This judgement is based on the very likely nova nature of the object and the presence of an apparently bright quiescent counterpart. The ASAS-3 public light curve suggests that the object can be a fast nova caught in the early rising stage. If the object is indeed a classical nova, and if the 16-th mag object is the real quiescent counterpart, it may even further brighten to a naked-eye object or a easy binocular object.

ASAS-3 position
R.A. = 18:49:37.7
Decl. = -9:33:52.7 (J2000.0).
Tentative quiescent identification:
18:49:37.684 -09:33:53.76 r=16.4 b=17.2 USNO-A2.0
18:49:37.663 -09:33:53.74 r=15.71       GSC-2.2
18:49:37.67  -09:33:53.9  r=15.87 b=17.47 USNO-B1.0
18:49:37.70  -09:33:54.1  J=14.318 H=14.007 K=13.818  2MASS
18:49:37.71  -09:33:53.9  DENIS-2

ASAS-3 data: 
Aug. 24.105   V>14.0
Aug. 26.096   V=10.15
Aug. 28.096   V=8.94

(Comparison of the ASAS-3 images, by courtesy of G. Pojmanski)

The discovery date was on August 28.577 UT (mag 8.5, T-Max). Further details of the discovery is expected to be soon announced in CBET or IAUC. When the discovery details are announced, we plan to provide a VSNET page on this object.

Regards,
Taichi Kato
VSNET Collaboration team
[According to IAUC 8190, the discovery was made by Hideo Nishimura, see IAUC 8190 for the details].

Already started fading?

(vsnet-discovery-nova 235)

I made a visual confirmation of a new bright stellar object at the position:

R.A. = 18:49:37.7
Decl. = -9:33:52.7 (J2000.0).

SCTnova2003 20030830.3416 9.5 LMK

Comp stars were TYC5693-2438-1 V=9.326
TYC5697-105-1 V=9.636
from Tycho2+Bessell corrections.

Mike Linnolt
Honolulu, HI
Dear Colleagues,

Mike Linnolt (Hawaii) just reported that the object was at 9.5 mag on August 30.3416 UT. This observation suggests that the object has not brightened as expected from the supposed quiescent identification. It may be either possible that the true quiescent object may be fainter, or that the object may not be a typical large-amplitude nova.

Regards,
Taichi Kato
VSNET Collaboration team

Multicolor Photometry

(vsnet-discovery-nova 237)

Possible Nova in Sct: multicolor observation by Nakajima-san

Kazuhiro Nakajima (Kumano, Mie, Japan) succeeded in obtaining the following multicolor CCD photometry of the suspected nova in Sct. The observed colors are not inconsistent with a moderately reddened nova. The object is likely a moderately remote object reaching its maximum around the discovery date. The supposed quiescent counterpart seems to be slightly too bright to be securely identified with this exploding object. Further detailed astrometry and identification are needed.

CCD magnitude estimates by VSOLJ members

object         YYYYMMDD(UT)   mag  code
SCTnova2003    20030830.53668 8.96C  Njh.VSOLJ
SCTnova2003    20030830.53800 9.05V  Njh.VSOLJ
SCTnova2003    20030830.54001 8.46Rc  Njh.VSOLJ
SCTnova2003    20030830.54163 10.13B  Njh.VSOLJ

instruments: 25cmSC(F-5) + CV-04 + V,Rc,B, filter

Relayed by Taichi Kato,
VSNET admin

Spectroscopic Information

(vsnet-discovery-nova 244)

An objective prism spectrum taken at Aug. 31.093 shows a very narrow and weak H-alpha emission with a peak approximately 0.47 times the intensity of the nearby continuum. The FWHM appears to be no more than 300 km/s.

All the best to all, Bill Liller

(vsnet-discovery-nova 245)

Nova Sct 2003: spectroscopy by Fujii

M. Fujii (Fujii Bisei Observatory) reports the following spectrum of the possible nova in Sct. The H-alpha and H-beta lines are clearly seen in emission (FWHM of the H-alpha 700 km/s). The object is confirmed to be an Fe-II class nova by the presence of Fe II series emissions. The NaD line is in absorption, consistent with the moderate reddening.


(M. Fujii's spectrum on Aug. 31)
(vsnet-discovery-nova 246)

My recent spectrum of Nova Sct posted at http://home.freeuk.com/m.gavin/nsct03.htm

The 'nova' does not display the classic nova spectrum but resembles V838 Mon = Pec Nova Mon 2002 about 2002 Feb 3/4.

regards 
Maurice Gavin
(vsnet-discovery-nova 247)

The following report has been submitted to IAU Circulairs

We have observed the possible nova in Scutum that was announced on IAUC 8190 with the 1.22 m telescope + B&C spectrograph + CCD in Asiago on Aug 31.97 UT, at 0.23 nm/pix dispersion over the range 372 - 491 nm in cloudy sky conditions. The Balmer series is weakly in emission down to H-epsilon, and the line width is not appreciably larger than the instrumental profile (300 km/sec). The Balmer line profiles show a weak absorption component blushifted by 500 km/sec and a second emission peak red shifted by 650 km/sec with respect to the main emission line. The well developed absorption spectrum closely match that of a normal F2 supergiant, with normal intensity for s-element lines of 455.4 BaII and 407.8, 421.6 SrII.

Corrado Boeche and Ulisse Munari, Asiago Observatory, Italy

Finding charts

Trondal's image and astrometry

I observed the nova this evening using my 25cm and MX916 CCD. The image is attached.

I also made a USNO-A2/DSS2 reference map for my observation of the R magnitude ( also attached ). I cut off stars fainter than 15.5. As usual I put Red magnitudes on top, and Blue at the bottom.

I also used Astroart 2.0 astrometry and got the nova's position : 18h 49m 37.59s -09o 33' 50".3 (J2000)

My observation :

SCTnova2003    20030830.807 10.0:R  TOL

Yours Sincerely
Odd Trondal

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