Note: Please continue coverage of this nova until further notice. - Elizabeth O. Waagen, 13 April 2020
Note: In the original version of this Alert Notice, it was omitted that the rebrightening of V1047 Cen (Nova Cen 2005) was discovered and reported by the Gaia team as Gaia19cfn on June 10, 2019. The target was subsequently observed by OGLE. We apologize sincerely for the omission of this discovery information. - Elizabeth O. Waagen
June 21, 2019: The classical (Fe II) nova V1047 Cen (Nova Cen 2005) is rebrightening, according to observations made by the OGLE team (ATel# 12876).
Dr. Fred Walter (Stony Brook University) has requested AAVSO observers to monitor this nova throughout its current activity in support of multiwavelength observations underway and additional multiwavelength observations likely to be scheduled. He notes that the rebrightening underway is unprecedented in a classical (Fe II) nova.
BVRcIc photometry is requested, with V and B taking priority, beginning immediately. Observations made nightly to a few times per night are requested. However, this cadence may change as the nova evolves and ToO observations by various researchers are scheduled. Updates will be announced in the AAVSO forum threads for this object (see links below). Once the nova has returned to minimum, please continue nightly snapshots for the rest of the observing season. Visual observations are also welcome.
Dr. Walter reports that as of 20 June 2019, ASASSN data show V1047 Cen at approximately V=15.3; he comments that the OGLE event seems to be very red. The most recent observation in the AAVSO International Database shows the nova at visual magnitude <14.0 on 2018 Aug. 14.897 UT (A. Plummer, Linden, NSW, Australia). An observation by L. A. G. Monard (Calitzdorp, South Africa) on 2011 May 23.793 UT gives <18 +/-0.3 CR. The International Variable Star Index (VSX) gives minimum magnitude 18.7 V.
P. Mroz and A. Udalski (Warsaw U. Observatory), on behalf of the OGLE team (ATel #12876), report: "Our observations show that the star has brightened by ~2.5 mag since April 6.11 UT, 2019, it has currently (June 12.04 UT, 2019) I = 14.77 ± 0.01 mag.
"Such a slow rebrightening is inconsistent with a recurrent nova explosion (as nova eruptions reach the peak within hours-days). The long-term pre-rebrightening variability and the slow rise are reminiscent to the light curve of a red nova V1309 Sco. We did not find, however, any periodic variability in our archival light curve of V1047 Cen."
V1047 Cen (Nova Cen 2005) was discovered on 2005 September 1.031 UT by William Liller (Viña del Mar, Chile) at photographic magnitude ~8.5 (IAU CBET 215); A. F. Jones (Nelson, New Zealand) reported a visual magnitude of 8.5 on Sep. 1.333 UT. The nova faded to <18 CR by May 2011.
Coordinates (J2000): R.A. 13 20 49.78 Dec. -62 37 50.6
Charts with a comparison star sequence for V1047 Cen may be created using the AAVSO Variable Star Plotter (VSP).
Please report all observations to the AAVSO International Database using the name V1047 CEN.
AAVSO Forums: This campaign continues to be the topic of the AAVSO Campaigns and Observation Reports forum thread https://www.aavso.org/v1047-cen-campaign-2019 and the Novae forum thread https://www.aavso.org/v1047-cen-campaign-2019-01
This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.
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