SOFIA Observations of Dust Formation in Nova V5668 Sgr (2015 #2)

American Association of Variable Star Observers (AAVSO)
Sat, 08/01/2015 - 18:39


Title:  SOFIA Observations of Dust Formation in Nova V5668 Sgr (2015
Author: Robert D. Gehrz (University of Minnesota), Aneurin Evans (University
                of Keele),Charles E. Woodward (University of Minnesota), Luke Keller
                (Ithaca College), L. Andrew Helton (USRA/SOFIA), Dinesh Shenoy (University
                of Minnesota), D. P. K. . Banerjee (Physical Research Laboratory,
                Ahmedabad, India), N. M. Ashok Physical (Research Laboratory, Ahmedabad,
                India), Sumner G. Starrfield (Arizona State University), Gregory Schwarz
                (American Astronomical Society), R. Mark Wagner (Large Binocular Telescope
                Observatory), Joachim Krautter (Landessternwarte Heidelberg), Stewart
                Eyres (University of Central Lancashire), Mark Rushton (University
                of Central Lancashire), Tiina Liimets (Tartu Observatory, University
                of Tartu), Shazrene S. Mohamed (South African Astronomical Observatory),
Posted: 1 Aug 2015; 16:05 UT
Subjects:Infra-Red, Nova

We have followed the early phases of dust formation in Nova V5668 Sgr (Nova
Sgr 2015 #2) with the FORCAST science instrument on the NASA Stratospheric
Observatory for Infrared Astronomy (SOFIA).  A spectrum on 2015 June 05,
that we interpret as showing the early nucleation phase, showed a ~ 1100
K dust continuum overlain by weak hydrogen emission lines. On 2015 July
06, the energy in the dust emission continuum had increased by a factor
of ~ 40, the grain temperature had fallen to ~ 750 K, and the dust continuum
had completely blanketed the hydrogen emission. We attribute these effects
to the rapid growth of the grains to sub-micron radii.