Discovery of a Bow-Shock Nebula around the Z Cam-type Cataclysmic Variable SY Cancri

Fuente: arXiv
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Autores principales: Bond, Howard E., Carter, Calvin, Elmore, David F., Goodhew, Peter, Patchick, Dana, Talbot, Jonathan
Formato: Preprint
Publicado: 2024
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author Bond, Howard E.
Carter, Calvin
Elmore, David F.
Goodhew, Peter
Patchick, Dana
Talbot, Jonathan
author_facet Bond, Howard E.
Carter, Calvin
Elmore, David F.
Goodhew, Peter
Patchick, Dana
Talbot, Jonathan
contents We report the serendipitous discovery of a bow-shock nebula around the cataclysmic variable (CV) SY Cancri. In addition, SY Cnc lies near the edge of a faint Halpha-emitting nebula with a diameter of about 15'. The orientation of the bow shock is consistent with the direction of SY Cnc's proper motion. Nebulae are extremely rare around CVs, apart from those known to have undergone classical-nova (CN) outbursts; bow shocks and off-center nebulae are even more unusual. Nevertheless, the properties of SY Cnc and its nebulosity are strikingly similar to those of V341 Ara, another CV that is also associated with a bow shock and is likewise off-center with respect to its faint Halpha nebula. Both stars are binaries with optically thick accretion disks, belonging to the classes of Z Cam CVs or nova-like variables. We discuss three scenarios to explain the properties of the nebulae. They may have resulted from chance encounters with interstellar gas clouds, with the stars leaving in their wakes material that is recombining after being photoionized by UV radiation from the CVs. Alternatively, the large nebulae could be ejecta from unobserved CN outbursts in the recent past, which have been decelerated through collisions with the interstellar medium (ISM), while the stars continue to snowplow through the gas. Or the faint Halpha nebulae may be ambient ISM that was shock-ionized by a CN outburst in the past and is now recombining.
format Preprint
id arxiv_https___arxiv_org_abs_2409_06835
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Discovery of a Bow-Shock Nebula around the Z Cam-type Cataclysmic Variable SY Cancri
Bond, Howard E.
Carter, Calvin
Elmore, David F.
Goodhew, Peter
Patchick, Dana
Talbot, Jonathan
Solar and Stellar Astrophysics
Astrophysics of Galaxies
We report the serendipitous discovery of a bow-shock nebula around the cataclysmic variable (CV) SY Cancri. In addition, SY Cnc lies near the edge of a faint Halpha-emitting nebula with a diameter of about 15'. The orientation of the bow shock is consistent with the direction of SY Cnc's proper motion. Nebulae are extremely rare around CVs, apart from those known to have undergone classical-nova (CN) outbursts; bow shocks and off-center nebulae are even more unusual. Nevertheless, the properties of SY Cnc and its nebulosity are strikingly similar to those of V341 Ara, another CV that is also associated with a bow shock and is likewise off-center with respect to its faint Halpha nebula. Both stars are binaries with optically thick accretion disks, belonging to the classes of Z Cam CVs or nova-like variables. We discuss three scenarios to explain the properties of the nebulae. They may have resulted from chance encounters with interstellar gas clouds, with the stars leaving in their wakes material that is recombining after being photoionized by UV radiation from the CVs. Alternatively, the large nebulae could be ejecta from unobserved CN outbursts in the recent past, which have been decelerated through collisions with the interstellar medium (ISM), while the stars continue to snowplow through the gas. Or the faint Halpha nebulae may be ambient ISM that was shock-ionized by a CN outburst in the past and is now recombining.
title Discovery of a Bow-Shock Nebula around the Z Cam-type Cataclysmic Variable SY Cancri
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2409.06835