V4742 Sgr = Nova Sgr 2002 (No. 2)

(CCD image taken by Berto Monard on Sep. 16)

Date: Sun, 15 Sep 2002 15:28:54 -0400
From: "W.Liller" 
Subject: Nova candidate

There seems to be a new stellar object at (2000) R.A. 18h 02.4m, Dec. -25d 18'. It appears on three photos taken at U.T. Sept. 15.1102, 15.1227 and 15.1241 with an 80mm f/1.4 lens, orange filter and Kodak TP film; its magnitude is approximately 8.5. Nothing brighter than mag 11.5 appears on two photos taken at U.T. Sept. 11.12.

Note that the magnitude is very uncertain owing to severe light pollution produced by the 8-day-old moon about 8.5 degrees away.

I'd appreciate your confirmation -- or whatever -- since the weather here in Vina del Mar has been very unstable. I will, however, try to get a spectrum, an improved position and some CCD magnitudes tonight.

All the best to all, William Liller

( vsnet-discovery-nova 83)

Hello,

I just checked my latest 2 pictures of the given coordinates, taken on September 3rd, 22h38m UT and 22h40m UT, limiting magnitude 10.5, and nothing could be seen in both. I will try to observe it tonight.

   Regards,
   Raquel Yumi Shida
   (AAVSO code: SQH)

While the light variation suggests a nova, there is a strong IRAS/MSX5C source close to this location (not registered as a variable star). Possible identification with this source needs to be closely examined as soon as possible. If the identification is confirmed, an explosion of such an IRAS source is quite unexpected.

180220.7 -251751 (2000.0) IRAS17592-2517 10.920 6.981 24.840L 440.400L 97%
180220.7 -251751 (2000.0) SSC17592-2517 10.920 6.981 24.840L 440.400L
180221.0 -251749 (2000.0) MSX5C_G005.0235-01.3649 -15 -8 7 8 6 6 V(%):-:-:2:5:3:3

Regards,
Taichi Kato

Confirmation

( vsnet-discovery-nova 85)

Observation of the 'nova' candidate discovered by William Liller. 25cm reflector at 76x:

020916.082 8.0

Star was slightly red.
Thank you,
Bob King
Duluth, MN USA 

Spectroscopic confirmation

Spectrum of the W. Liller nova for the date Sept 16.806, 2002 UT at :

http://astrosurf.com/buil/us/nsgr2/nsgr2.htm

8-inch telescope and a 0.38 A/pixel dispersion spectrograph. Difficult weather.

The measured expension velocity is of 1100 km/s (FWHM of H-alpha line). Very deep P-Cygny profle. A young nova...

Christian Buil
Web: http://astrosurf.com/buil

Astrometry

Nova Sgr 2002 No. 2: precise astrometry

Precise astrometry using a image taken by B. Monard on Sept. 16.7 UT yield the position of Nova Sgr 2002 No. 2 as:

R.A. = 18:02:21.864, Decl. = -25:20:32.22 (J2000.0)

, with 102 UCAC1 reference stars (fitting error ~ 0".2). It suggests that a GSC-2.2 star which Dr. Skiff and I mentioned is not a quiesient counterpart of the nova; no source can be seen on every DSS images within 3" from this position.

Sincerely Yours,
Hitoshi Yamaoka

Charts

We have prepared a chart (2.5 x 3.0 degrees field) of this bright (possible) nova with comparison stars with VT-magnitudes down to magnitude 11.5 selected from Tycho-2, and placed it at the following

URL:
http://www.shopplaza.nl/astro/vs-charts/nova2002SGE.htm

Reinder Bouma/ Edwin van Dijk

Chart by Japan Variable Stars Study Association

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