Alert Notice 420: Nova in Sagittarius (V5586 Sgr = Nova Sgr 2010 No. 2)

April 26, 2010

Discovered By: Koichi Nishiyama, Kurume, Japan, and Fujio Kabashima, Miyaki, Japan

Discovery Date: Apr. 23.782 UT using a 105-mm f/4 camera lens (+ SBIG STL6303E camera)

Discovery Magnitude: unfiltered CCD magnitude 11.2

Position: R.A = 17:53:02.99 +/- 0.01s, Decl. = -28:12:19.4 +/-0.1" (equinox 2000.0)
from five unfiltered CCD frames taken around Apr. 23.791

Spectra: Spectroscopic observations by L. A. Helton, T. Vonderharr, and C. E. Woodward, University of Minnesota; and G. J. Schwarz, American Astronomical Society, obtained at the Steward Observatory Bok 2.29-m telescope on Apr. 25.4 UT confirm that V5586 Sgr is a post-maximum classical nova. The emission lines are superimposed on a continuum that rises sharply to the red. The lack of any blue emission lines in the spectrum, along with the climbing red continuum, suggests that the nova is subjected to an exceptionally high degree of extinction. The red spectrum is similar to that of Nova Pup 1991 (V351 Pup; Williams et al. 1994, Ap.J. Suppl. 90, 297).

Observations Reported to the AAVSO (via IAU Circular 9140): (via unfiltered CCD, and from Nishiyama and Kabashima, unless noted otherwise):

1996 Sept. 12, <17.5 (Digitized Sky Survey, red plate);

2010 Apr. 2.831, <12.9;

16.749, <13.1;

20.262, <11.0, W. Liller, Vina del Mar, Chile (Kodak TP film, orange filter, 85-mm camera lens);

24.660, 11.1, T. Yusa, Osaki, Japan;

24.673, 11.6, Nishiyama and Kabashima;

24.752, 10.21 Ic, H. Maehara, Kwasan Observatory, Kyoto University;

24.754, 12.47 Rc, Maehara;

24.755, 15.33 V, Maehara;

25.4, 12.1, E. Guido and G. Sostero (remotely with a 0.25-m reflector from GRAS Observatory near Mayhill, NM).

Charts: Finder charts for V5586 Sgr may be plotted by entering the coordinates above into VSP: http://www.aavso.org/vsp

Reporting Observations: Please report all observations to the AAVSO as V5586 SGR. N Sgr 2010 No. 2 or its AUID 000-BJV-281 may also be used, but V5586 SGR is preferred.

Notes: a. A USNO-B1.0-catalogue star of red mag 17.4 has position end figures 03.11s, 19.0". T. Yusa, Osaki, Japan, reports position end figures 02.98s, 19.3" on an image taken April 24.660 UT. E. Guido and G. Sostero report position end figures 02.99s, 19.3" on CCD images obtained Apr. 25.4 UT remotely with a 0.25-m reflector from GRAS Observatory near Mayhill, NM. A comparison between their image and a Digitized Sky Survey 1980cinfrared plate is posted at website URL http://bit.ly/bH6fps.

b. E. V. Kazarovets reports that the GCVS team has assigned Nova Sgr 2010 No. 2 the name V5586 SGR.

c. Initially announced in CBET 2261 (Daniel W. E. Green, ed.), with additional information in CBET 2264 (Daniel W. E. Green, ed.). The information in this Alert Notice is taken from the IAU CBETs and IAU Circular 9140 (Daniel W. E. Green, ed.).

Congratulations to Koichi Nishiyama and Fujio Kabashima on their latest discovery!

Good observing, Elizabeth O. Waagen Senior Technical Assistant

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