Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables

We report discoveries of bow-shock nebulae, seen in H α and [O iii ] λ 5007, around two cataclysmic variables (CVs): LS Pegasi and ASASSN-V J205457.73+515731.9 (ASASJ2054). Additionally, both stars lie near the edges of faint extended H α -emitting nebulae. The orientations of the bow shocks are con...

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Main Authors: Howard E. Bond, Calvin Carter, Eric Coles, Peter Goodhew, Dana Patchick, Jonathan Talbot, Gregory R. Zeimann
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astronomical Journal
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Online Access:https://doi.org/10.3847/1538-3881/add88d
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author Howard E. Bond
Calvin Carter
Eric Coles
Peter Goodhew
Dana Patchick
Jonathan Talbot
Gregory R. Zeimann
author_facet Howard E. Bond
Calvin Carter
Eric Coles
Peter Goodhew
Dana Patchick
Jonathan Talbot
Gregory R. Zeimann
author_sort Howard E. Bond
collection DOAJ
description We report discoveries of bow-shock nebulae, seen in H α and [O iii ] λ 5007, around two cataclysmic variables (CVs): LS Pegasi and ASASSN-V J205457.73+515731.9 (ASASJ2054). Additionally, both stars lie near the edges of faint extended H α -emitting nebulae. The orientations of the bow shocks are consistent with the directions of the objects’ proper motions. The properties of LS Peg and ASASJ2054, and of their nebulae, are remarkably similar to those of SY Cancri (SY Cnc), which we described in a recent paper; SY Cnc is a CV likewise associated with a bow shock and an off-center H α nebula. These objects join V341 Arae and BZ Camelopardalis, CVs that are also accompanied by similar nebulae. All five stars belong to the nova-like variable (NLV) subclass of CVs, characterized by luminous optically thick accretion disks that launch fast winds into the surrounding space. We suggest that the bow shocks and nebulae result from chance encounters of the NLVs with interstellar gas clouds, with the stars leaving in their wakes Strömgren zones that are recombining after being photoionized by the CVs’ ultraviolet and X-ray radiation. Our discoveries illustrate the power of small telescopes equipped with modern instrumentation, and used to accumulate extremely long exposure times, for the detection of very low-surface-brightness nebulae.
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spelling doaj-art-9b3b296474e84ed68aa6b17ec766fa002025-08-20T03:33:15ZengIOP PublishingThe Astronomical Journal1538-38812025-01-0117027810.3847/1538-3881/add88dTwo More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic VariablesHoward E. Bond0https://orcid.org/0000-0003-1377-7145Calvin Carter1https://orcid.org/0009-0008-5193-4053Eric Coles2Peter Goodhew3https://orcid.org/0009-0005-3715-4374Dana Patchick4https://orcid.org/0000-0002-9018-9606Jonathan Talbot5https://orcid.org/0009-0009-3986-4336Gregory R. Zeimann6https://orcid.org/0000-0003-2307-0629Department of Astronomy & Astrophysics, Penn State University , University Park, PA 16802, USA ; heb11@psu.edu; Space Telescope Science Institute , 3700 San Martin Dr., Baltimore, MD 21218, USARocket Girls Ranch Observatory , 7215 Paldao Dr., Dallas, TX 75240, USASierra Remote Observatories , 42130 Bald Mountain Rd., Auberry, CA 93602, USADeep Space Imaging Network , 108 Sutton Court Rd., London W4 3EQ, UKDeep Sky Hunters Consortium , 1942 Butler Ave., Los Angeles, CA 90025, USAStark Bayou Observatory , 1013 Conely Cir., Ocean Springs, MS 39564, USAHobby-Eberly Telescope, University of Texas at Austin , Austin, TX 78712, USAWe report discoveries of bow-shock nebulae, seen in H α and [O iii ] λ 5007, around two cataclysmic variables (CVs): LS Pegasi and ASASSN-V J205457.73+515731.9 (ASASJ2054). Additionally, both stars lie near the edges of faint extended H α -emitting nebulae. The orientations of the bow shocks are consistent with the directions of the objects’ proper motions. The properties of LS Peg and ASASJ2054, and of their nebulae, are remarkably similar to those of SY Cancri (SY Cnc), which we described in a recent paper; SY Cnc is a CV likewise associated with a bow shock and an off-center H α nebula. These objects join V341 Arae and BZ Camelopardalis, CVs that are also accompanied by similar nebulae. All five stars belong to the nova-like variable (NLV) subclass of CVs, characterized by luminous optically thick accretion disks that launch fast winds into the surrounding space. We suggest that the bow shocks and nebulae result from chance encounters of the NLVs with interstellar gas clouds, with the stars leaving in their wakes Strömgren zones that are recombining after being photoionized by the CVs’ ultraviolet and X-ray radiation. Our discoveries illustrate the power of small telescopes equipped with modern instrumentation, and used to accumulate extremely long exposure times, for the detection of very low-surface-brightness nebulae.https://doi.org/10.3847/1538-3881/add88dEmission nebulaeCataclysmic variable starsNova-like variable starsVY Sculptoris starsStellar bow shocksClassical novae
spellingShingle Howard E. Bond
Calvin Carter
Eric Coles
Peter Goodhew
Dana Patchick
Jonathan Talbot
Gregory R. Zeimann
Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables
The Astronomical Journal
Emission nebulae
Cataclysmic variable stars
Nova-like variable stars
VY Sculptoris stars
Stellar bow shocks
Classical novae
title Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables
title_full Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables
title_fullStr Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables
title_full_unstemmed Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables
title_short Two More Bow Shocks and Off-center Hα Nebulae Associated with Nova-like Cataclysmic Variables
title_sort two more bow shocks and off center hα nebulae associated with nova like cataclysmic variables
topic Emission nebulae
Cataclysmic variable stars
Nova-like variable stars
VY Sculptoris stars
Stellar bow shocks
Classical novae
url https://doi.org/10.3847/1538-3881/add88d
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