The optical re-brightening of M31N 2017-09a
ATel #11070; Hanjie Tan (Chinese Culture University), David Boyd (BAA VSS), Xing Gao (Xinjiang Astronomical Observatory), Seiichiro Kiyota (VSOLJ), Jingyuan Zhao, Mi Zhang, Guoyou Sun (Xingming Observatory Sky Survey Group), Christopher Lloyd (University of Sussex)
on 16 Dec 2017; 23:06 UT
Credential Certification: Christopher Lloyd (email@example.com)
Subjects: Optical, Nova, Transient
We report the optical re-brightening of the Fe II class nova M31N 2017-09a
which was first reported as a transient by Zhang et al., (2017,
TNS Discovery Report)
at unfiltered magnitude 18.8 on 2017-08-30.7 UT (JD=2457997.2). On the following night it was magnitude 18.6 and earlier observations put the upper limit of the precursor at magnitude 19.5.
Spectroscopy by Williams & Darnley (2017, ATel #10741) taken approximately 11 days later showed broad Balmer emission lines (Hα, Hβ, Hγ) and Fe II emission lines, confirming its classification as a classical Fe II class nova.
Unpublished photometry by the
(IAU code C42), the Sierra Remote Observatory and the West Challow Observatory (IAU code J90) suggest the original outburst peaked at unfiltered magnitude 17.8 around 2017-09-03, faded to below magnitude 19.5 by 2017-09-06 and remained fainter than this until 2017-12-07 when it was seen at magnitude 19.2.
The final re-brightening occurred between 2017-12-13.5 UT from magnitude 19.2 and 2017-12-14.5 UT where three observations put the magnitude ~ 18.8. The most recent observations give V = 18.56(7) at 2017-12-14.7 UT and unfiltered magnitude 18.7 at 2017-12-15.1 UT suggesting that the transient is brightening.
Further observations are encouraged.