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From Observation to Simulation: Understanding Surprising Evolutions in Nova Ejecta

F. Healy, T. J. O’Brien, R. Beswick, M. K. Argo

Transactions of IAA RAS, issue 41, 9–17 (2017)

Keywords: VLBI, Astrometry

Abstract

A classical nova occurs when a white dwarf (WD) in an interacting binary system undergoes a thermonuclear runaway (TNR) on its surface, leading to a large expulsion of material into the interstellar medium, as well as a dramatic optical brightening. Simple isothermal, spherically symmetric, homogeneous models for thermal radio emission from novae predict a light curve which brightens as t² (while the ejected shell is optically thick) and then declines as t¯³ (once it becomes optically thin). However, observations of novae indicate that these models are flawed. For example, e-MERLIN, VLBI and VLA observations of Nova Mon 2012 have shown a complex, aspherical ejecta which evolves over time, whilst other studies have shown light curves which are not in agreement with the predictions of the models. In this talk we present new modelling of the radio emission from a variety of hypothesized ejecta structures. These models allow improved estimation of mass loss rate, which in turn tell us more about the mechanisms whereby the mass is lost, and allow us to investigate classical novae as possible Type 1a supernova progenitors. Developing an understanding of the geometry and possible collimation of the ejecta may also have implications for the study of particle acceleration in radio novae and similar systems.

Citation

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F. Healy, T. J. O’Brien, R. Beswick, M. K. Argo. From Observation to Simulation: Understanding Surprising Evolutions in Nova Ejecta // Transactions of IAA RAS. — 2017. — Issue 41. — P. 9–17.

@article{healy2017,
  abstract = {A classical nova occurs when a white dwarf (WD) in an interacting binary system undergoes a thermonuclear runaway (TNR) on its surface, leading to a large expulsion of material into the interstellar medium, as well as a dramatic optical brightening. Simple isothermal, spherically symmetric, homogeneous models for thermal radio emission from novae predict a light curve which brightens as t² (while the ejected shell is optically thick) and then declines as t¯³ (once it becomes optically thin). However, observations of novae indicate that these models are flawed. For example, e-MERLIN, VLBI and VLA observations of Nova Mon 2012 have shown a complex, aspherical ejecta which evolves over time, whilst other studies have shown light curves which are not in agreement with the predictions of the models. In this talk we present new modelling of the radio emission from a variety of hypothesized ejecta structures. These models allow improved estimation of mass loss rate, which in turn tell us more about the mechanisms whereby the mass is lost, and allow us to investigate classical novae as possible Type 1a supernova progenitors. Developing an understanding of the geometry and possible collimation of the ejecta may also have implications for the study of particle acceleration in radio novae and similar systems.},
  author = {F. Healy and T.~J. O’Brien and R. Beswick and M.~K. Argo},
  issue = {41},
  journal = {Transactions of IAA RAS},
  keyword = {VLBI, Astrometry},
  pages = {9--17},
  title = {From Observation to Simulation: Understanding Surprising Evolutions in Nova Ejecta},
  url = {http://iaaras.ru/en/library/paper/1695/},
  year = {2017}
}

TY  - JOUR
TI  - From Observation to Simulation: Understanding Surprising Evolutions in Nova Ejecta
AU  - Healy, F.
AU  - O’Brien, T. J.
AU  - Beswick, R.
AU  - Argo, M. K.
PY  - 2017
T2  - Transactions of IAA RAS
IS  - 41
SP  - 9
AB  - A classical nova occurs when a white dwarf (WD) in an interacting
binary system undergoes a thermonuclear runaway (TNR) on its surface,
leading to a large expulsion of material into the interstellar
medium, as well as a dramatic optical brightening. Simple isothermal,
spherically symmetric, homogeneous models for thermal radio emission
from novae predict a light curve which brightens as t² (while the
ejected shell is optically thick) and then declines as t¯³ (once it
becomes optically thin). However, observations of novae indicate that
these models are flawed. For example, e-MERLIN, VLBI and VLA
observations of Nova Mon 2012 have shown a complex, aspherical ejecta
which evolves over time, whilst other studies have shown light curves
which are not in agreement with the predictions of the models. In
this talk we present new modelling of the radio emission from a
variety of hypothesized ejecta structures. These models allow
improved estimation of mass loss rate, which in turn tell us more
about the mechanisms whereby the mass is lost, and allow us to
investigate classical novae as possible Type 1a supernova
progenitors. Developing an understanding of the geometry and possible
collimation of the ejecta may also have implications for the study of
particle acceleration in radio novae and similar systems.
UR  - http://iaaras.ru/en/library/paper/1695/
ER  -