Dust Forming in the Classical Nova V1656 Sco
ATel #9673; Frederick M Walter
on 26 Oct 2016; 21:44 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Fred Walter (frederick.walter@stonybrook.edu)
Subjects: Infra-Red, Optical, Nova
Ongoing 7-band photometry of the nova V1656 Sco (ASASSN-16kd; ATel 9469)
with the Andicam imager
on the SMARTS 1.3m at CTIO shows that dust is very likely forming.
The brightness has been decaying smoothly in the B, V, R, I, and J bands.
The decay in the K band stopped about 2016 October 6 (MJD 57665.5; day 27 after
discovery). As of 24 October (MJD 57686.5) the brightness at K has increased
by 2.5 mag relative to the decay at BVRIJ. A corresponding increase in flux in the H band
began about 10 October (MJD 57672.5); as of 24 October the nova has brightened by
1.3 mag relative to the shorter wavelengths.
On MJD 57686.50 the BVRIJHK magnitudes were 17.2, 16.0, 13.6, 13.0, 10.6, 9.5,
and 7.9, respectively.
There is no evidence for a dust dip at optical wavelengths. Since 3 October
the BVRIJ brightnesses have faded monotonically by 0.05 +/- 0.01 mag/day.
As the nova is rapidly approaching the Sun, near-IR spectroscopy to examine
the dust would be timely.