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Alert Notice 461: Nova Scorpii 2012 = MOA 2012 BLG-320 [V1324 Sco]

12 June 2012

Nova Scorpii 2012 = MOA 2012 BLG-320  [V1324 Sco]

Discovered by: R. M. Wagner (Ohio State University (OSU) and Large Binocular Telescope Observatory), S. Dong (Institute for Advanced Study, Princeton), T. Bensby (Lund Observatory), J. Prieto (Princeton University), I. Bond (Massey University), P. Tristram (Mt. John University Observatory), D. Bennett (University of Notre Dame), K. Wada and T. Sumi (Osaka University), and the Microlensing Observations in Astrophysics (MOA) collaboration; A. Gould (OSU), and the Microlensing Follow-Up Network (microFUN) collaboration; and S. Starrfield (Arizona State University)

Discovery Magnitude: magnitude I = 18.5

Discovery date: 2012 May 22.80 UT

Coordinates: RA 17 50 53.90, Dec -32 37 20.5 (2000.0)

Spectra: A high-resolution optical spectrum obtained June 4.08 UT with the Very Large Telescope (+ UVES) indicates the object is most likely a slow Fe II-type nova.

Observations reported to the AAVSO:
8.4870, 11.3 V +/-0.09 (R. Pickard, Leominster, England, with Faulkes Telescope Network);
8.4910, 12.8 B 0.2 (Pickard, with FTN);
8.5043, 11.305 V 0.033 (Pickard);
8.5063, 11.306 V 0.034 (Pickard);
9.1493, 11.6 (A. Amorim, Florianopolis, Brazil);
9.3641, 11.096 V 0.026 (C. Hergenrother, Tucson, AZ);
9.4833, 11.0 (H. Matsuyama, Kanimbla, QLD, Australia);
9.5064, 13.048 B 0.013 (T. Bohlsen, Armidale, NSW, Australia);
9.5073, 13.041 B 0.013 (Bohlsen);
9.5090, 13.040 B 0.013 (Bohlsen);
9.5119, 10.976 V 0.005 (Bohlsen);
9.5142, 10.975 V 0.005 (Bohlsen);
9.5159, 10.972 V 0.005 (Bohlsen);
10.3613, 10.817 V0.018 (Hergenrother);
10.4556, 10.9 (Matsuyama);
11.3567, 10.422 V 0.032 (Hergenrother);
11.3576, 12.290 B 0.046 (Hergenrother);
11.4674, 10.5 (Matsuyama);

Charts: Finder charts for N Sco 2012 may be plotted using the AAVSO International Variable Star Plotter (VSP) at

Please report observations to the AAVSO International Database as N SCO 2012.

a. Initially announced 2012 June 8 in IAU Central Bureau Electronic Telegram 3136 (Michael Rudenko, ed.).

b. Candidate microlensing event detected by the MOA collaboration and designated MOA 2012 BLG-320.

c. According to Wagner et al., no significant source appears at this position on either the R or N survey plates of the Digitized Sky Survey.

d. From CBET 3136: MOA photometry of the source before the outburst shows that the progenitor was at I magnitude about
19.0-19.5, but with substantial variability on nightly time scales.  Between May 14 and 16 UT, the source began a slow monotonic increase in brightness, and after May 24 UT, the rate increased significantly.  The light curve obtained between May 28 and 31 UT exhibits periodic modulations with an amplitude of about 0.1 mag and a period of about 1.6 hr superposed on the brightening source.  Between June 1.77 and 2.55 UT, the transient brightened dramatically from I magnitude about 17, reaching I magnitude about 11 on June 3.33 UT, prompting more detailed follow-up by both MOA and the microFun collaborations.

e. From CBET 3136: Photometry obtained on June 7.29 UT from images obtained with the Cerro Tololo 1.3-m telescope (+ ANDICAM) are magnitudes V = 11.6 and I = 9.4.  The transient continues to brighten at a rate of about 0.4 mag/day in the I band over the past three nights.

Congratulations to the MOA on their discovery!

This AAVSO Alert Notice was prepared by Elizabeth O. Waagen.


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