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Alert Notice 496: Outburst of the recurrent nova V745 Sco

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February 7, 2014

Event: Outburst of the recurrent nova V745 Sco

Discovery by: Rod Stubbings (Tetoora Road, VIC, Australia)

Discovery magnitude: 9.0 (visual)

Discovery date: 2014 February 6.694 UT

Coordinates:  R.A. 17 55 22.27   Dec. -33 14 58.5  (2000.0)

Observing Recommendations: This recurrent nova is fading quickly. Follow-up observations of all types (visual, CCD, DSLR) are strongly encouraged, as is spectroscopy. V745 Sco is currently a pre-dawn object, posing an additional challenge. AAVSO Nova Section advisor Dr. Jeno Sokoloski (Columbia University) has requested as much photometry and spectroscopy as possible. Professional researchers are planning multiwavelength observations for V745 Sco, and your observations will be extremely important for correlation of these multiwavelength data.

Outbursts of recurrent novae are relatively rare events. Each outburst is an opportunity to add to the study of the relationship between recurrent novae and the progenitors of Type-Ia supernovae, so the most complete coverage possible is important.

Dr. Bradley Schaefer (Louisiana State University) suggests that fast time-series of this nova may be useful to detect possible flaring activity as was observed during the outburst of U Scorpii in 2010.  He suggests that coincident time-series by multiple observers would be most useful for such a study, with a V-filter being preferred.

Observations reported to the AAVSO:
2013 Oct. 27.41528 UT, <13.3 (MTH, H. Matsuyama, Kanimbla, QLD, Australia);
28.42639, <12.8 (Matsuyama);
28.44375, <14.1 TG (KBJ, R. Kaufman, Bright, VIC, Australia);
29.44167, <14.1 TG (Kaufman);
2014 Jan. 12.73958, <12.7 TG (Kaufman);
Feb. 01.1, 13.98 I (MLF, L. Monard, Calitzdorp, South Africa, via cba-chat);
03.1, 13.78 I (Monard, via cba-chat);
05.696, <13.0 (SRX, R. Stubbings, Tetoora Road, VIC, Australia);
06.694, 9.0 (Stubbings);
06.745, 9.0 (CMQ, P. Camilleri, Warners Bay, Newcastle, NSW, Australia);
06.77330, 8.66 V +/-0.06 (OCN, S. O'Connor, St. Georges, Bermuda, remotely using iTel17, Siding Spring, NSW, Australia);
06.77390, 9.46 B +/-0.07 (O'Connor, remotely);
06.77450, 7.98 R +/-0.05 (O'Connor, remotely);
07.102, 9.04 V (Monard, via cba-chat);
07.104, 7.40 I (Monard, via cba-chat);
07.34557, 9.483V +/-0.010 (HMB, J. Hambsch, Mol, Belgium, remotely at San Pedro de Atacama, Chile);
07.35522, 9.485 V +/-0.010 (Hambsch, remotely);
07.36012, 9.490 V +/-0.009 (Hambsch, remotely);
07.36503, 9.520 V +/-0.008 (Hambsch, remotely);
07.37016, 9.515 V +/-0.009 (Hambsch, remotely);
07.37464, 9.508 V +/-0.008 (Hambsch, remotely);
07.38047, 9.549 V +/-0.008 (Hambsch, remotely);
07.38520, 9.563 V +/-0.008 (Hambsch, remotely);
07.76300, 10.07 V +/-0.03 (O'Connor, remotely);
07.76500, 8.91 R +/-0.09 (O'Connor, remotely);
07.76600, 8.15 I +/-0.01 (O'Connor, remotely);
07.80903, 10.1 (PEX, A. Pearce, Nedlands, W. Australia);
07.85833, 10.2 (Pearce);

Charts: Charts for V745 Sco may be created using the AAVSO Variable Star Plotter (VSP) at http://www.aavso.org/vsp.

Submit observations: Please submit observations to the AAVSO International Database using the name V745 SCO.

Notes:
a. Initially announced in AAVSO Special Notice #380 (M. Templeton).

b. Confirmed by Steve O'Connor (OCN, St. Georges, Bermuda) and Paul Camilleri (CMQ, Warners Bay, Newcastle, NSW, Australia); see Observations above.

c. Previous outbursts occurred in 1937 and 1989. The 1937 outburst was detected in 1958 (in decline at magnitude 11.0 on 1937 May 11.1 UT; outburst had occurred within the previous 19 days) by Lukas Plaut on plates taken by Hendrik van Gent at the Leiden Observatory; the object was announced as Nova Sco 1937 and later assigned the GCVS name V745 Sco. The 1989 outburst was detected on 1989 July 30.08 UT by William Liller (LIW, Vina del Mar, Chile), at magnitude 9.7 (PROBLICOM discovery using 2415 film with orange filter). [This Alert Notice originally reported that the 1989 outburst was discovered on 1989 August 1.55 UT by Mati Morel (MMAT, Thornton, NSW, Australia) at visual magnitude 10.4 and in decline. Morel's observation was the first one recorded in the AAVSO International Database, not the discovery one. Our sincere apologies to Bill Liller for the error.]

d. Dr. Bradley Schaefer (Louisiana State University) reports (2010ApJS..187..275S) in his comprehensive analysis of the 10 known galactic recurrent novae (including V745 Sco) that the median interval between recurrent novae outbursts is 24 years. The interval since the 1989 outburst of V745 Sco is 24.10 years.

Congratulations to Rod Stubbings on his detection of the outburst of this difficult pre-dawn recurrent nova!


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

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