TY - JOUR
T1 - A Mystery in Chamaeleon
T2 - Serendipitous Discovery of a Galactic Symbiotic Nova
AU - Lancaster, Lachlan
AU - Greene, Jenny E.
AU - Ting, Yuan Sen
AU - Koposov, Sergey E.
AU - Pope, Benjamin J.S.
AU - Beaton, Rachael L.
N1 - Publisher Copyright:
© 2020. The Author(s). Published by the American Astronomical Society..
PY - 2020/9
Y1 - 2020/9
N2 - We present the serendipitous discovery of a low optical-luminosity nova occurring in a D-type symbiotic binary star system in the Milky Way. We lay out the extensive archival data alongside new follow-up observations related to the stellar object CN Cha in the constellation of Chamaeleon. The object had long period (250 days), high amplitude (3 mag) optical variability in its recent past, preceding an increase in optical brightness by 8 magnitudes and a persistence at this brightness for about 3 yr, followed by a period of 1.4 mag yr-1 dimming. The object's current optical luminosity seems to be dominated by Hα emission, which also exhibits blueshifted absorption (a P-Cygni-like profile). After consideration of a number of theories to explain these myriad observations, we determine that CN Cha is most likely a symbiotic (an evolved-star-white-dwarf binary) system that has undergone a long-duration, low optical brightness, nova, placing it squarely in the class of so-called "slow novae,"of which there are only a few known examples. The duration of the optical plateau in CN Cha would make it the shortest timescale plateau of any known slow symbiotic novae.
AB - We present the serendipitous discovery of a low optical-luminosity nova occurring in a D-type symbiotic binary star system in the Milky Way. We lay out the extensive archival data alongside new follow-up observations related to the stellar object CN Cha in the constellation of Chamaeleon. The object had long period (250 days), high amplitude (3 mag) optical variability in its recent past, preceding an increase in optical brightness by 8 magnitudes and a persistence at this brightness for about 3 yr, followed by a period of 1.4 mag yr-1 dimming. The object's current optical luminosity seems to be dominated by Hα emission, which also exhibits blueshifted absorption (a P-Cygni-like profile). After consideration of a number of theories to explain these myriad observations, we determine that CN Cha is most likely a symbiotic (an evolved-star-white-dwarf binary) system that has undergone a long-duration, low optical brightness, nova, placing it squarely in the class of so-called "slow novae,"of which there are only a few known examples. The duration of the optical plateau in CN Cha would make it the shortest timescale plateau of any known slow symbiotic novae.
UR - http://www.scopus.com/inward/record.url?scp=85090290329&partnerID=8YFLogxK
U2 - 10.3847/1538-3881/aba435
DO - 10.3847/1538-3881/aba435
M3 - Article
SN - 0004-6256
VL - 160
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
M1 - 125
ER -