EX Draconis: Using Eclipses to Separate Outside-In and Inside-Out Outbursts. (arXiv:2004.06802v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Court_J/0/1/0/all/0/1">James M. C. Court</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Scaringi_S/0/1/0/all/0/1">Simone Scaringi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Littlefield_C/0/1/0/all/0/1">Colin Littlefield</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Segura_N/0/1/0/all/0/1">Noel Castro Segura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Long_K/0/1/0/all/0/1">Knox S. Long</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maccarone_T/0/1/0/all/0/1">Thomas Maccarone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Altamirano_D/0/1/0/all/0/1">Diego Altamirano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Degenaar_N/0/1/0/all/0/1">Nathalie Degenaar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wijnands_R/0/1/0/all/0/1">Rudy Wijnands</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shahbaz_T/0/1/0/all/0/1">Tariq Shahbaz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhan_Z/0/1/0/all/0/1">Zhuchang Zhan</a>
We present a study of the eclipses in the accreting white dwarf EX Dra during
TESS Cycles 14 and 15. During both of the two outbursts present in this
dataset, the eclipses undergo a hysteretic loop in
eclipse-depth/out-of-eclipse-flux space. In each case, the direction in which
the loops are executed strongly suggests an outburst which is triggered near
the inner edge of the accretion disk and propagates outwards. This in turn
suggests that the outbursts in EX Dra are ‘Inside Out’ outbursts; events
predicted by previous hydrodynamic studies of dwarf nova accretion disks and
confirmed spectroscopically in a number of other accreting white dwarf systems.
We therefore propose that the direction of the loop executed in
eclipse-depth/out-of-eclipse flux space be used as a test to phenomenologically
distinguish between ‘inside out’ and ‘outside in’ outbursts in other eclipsing
dwarf novae; a reliable and purely photometric test to differentiate between
these phenomena.
We present a study of the eclipses in the accreting white dwarf EX Dra during
TESS Cycles 14 and 15. During both of the two outbursts present in this
dataset, the eclipses undergo a hysteretic loop in
eclipse-depth/out-of-eclipse-flux space. In each case, the direction in which
the loops are executed strongly suggests an outburst which is triggered near
the inner edge of the accretion disk and propagates outwards. This in turn
suggests that the outbursts in EX Dra are ‘Inside Out’ outbursts; events
predicted by previous hydrodynamic studies of dwarf nova accretion disks and
confirmed spectroscopically in a number of other accreting white dwarf systems.
We therefore propose that the direction of the loop executed in
eclipse-depth/out-of-eclipse flux space be used as a test to phenomenologically
distinguish between ‘inside out’ and ‘outside in’ outbursts in other eclipsing
dwarf novae; a reliable and purely photometric test to differentiate between
these phenomena.
http://arxiv.org/icons/sfx.gif
