On the possible triple central star system of PN SuWt 2: No ménage à trois at the heart of the Wedding Ring

Abstract

SuWt 2 is a planetary nebula consisting of a bright ring-like waist from which protrude faint extended lobes - a morphology believed to be typical of progenitors which have experienced a close-binary evolution. Previous observations of NSV 19992, the star at the projected centre of SuWt 2, have found it to comprise two A-type stars in a 4.9 day eclipsing orbit, neither of which could be the nebular progenitor. Radial velocity studies provided a hint that the systemic velocity of this double A-type binary might be varying over time, suggesting the presence of a third component hypothesised to be the nebular progenitor. Here, we present an extensive radial velocity monitoring study of NSV 19992, performed with the high-resolution echelle spectrograph UVES mounted on ESO's VLT, in order to constrain the possible variation in the systemic velocity of the A-type binary and its relation to the progenitor of SuWt 2. The observations, acquired over a period of approximately one year, show no evidence of variability in the systemic velocity of NSV 19992. Combining these new observations with previous high-resolution spectroscopy demonstrates that the systemic velocity is also stable over much longer periods and, moreover, is distinct from that of SuWt 2, strongly indicating that the two are not associated. We conclude that NSV 19992 is merely a field star system, by chance lying in the same line of sight as the nebular centre, and that it bares no relation to SuWt 2 or its, as yet unidentified, central star(s).

arXiv commentAccepted to MNRAS. 6 pages, 4 figures, 2 tables

References in corpus (18)

• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• The Hα surface brightness - radius relation: a robust statistical distance indicator for planetary nebulae
• Binary Planetary Nebulae Nuclei towards the Galactic Bulge. I. Sample Discovery, Period Distribution and Binary Fraction
• Evolution of Massive Black Hole Binaries
• Observational Confirmation of a Link Between Common Envelope Binary Interaction and Planetary Nebula Shaping
• Identifying close binary central stars of PN with Kepler
• And in the Darkness Bind Them: Equatorial Rings, B[e] Supergiants, and the Waists of Bipolar Nebulae
• Binary central stars of planetary nebulae with long orbits: the radial velocity orbit of BD+33.2642 (PN G052.7+50.7) and the orbital motion of HD112313 (PN LoTr5)
• Abell 41: shaping of a planetary nebula by a binary central star?
• The influence of binarity on dust obscuration events in the planetary nebula M 2-29 and its analogues
• Observations and three-dimensional ionization structure of the planetary nebula SuWt 2
• An occultation event in a triple post-AGB star
• The Exotic Eclipsing Nucleus of the Ring Planetary Nebula SuWt2
• HIP 3678: a hierarchical triple stellar system in the centre of the planetary nebula NGC 246
• Kinematics of the ring-like nebula SuWt 2

Cited by in corpus (12)

• IRC +10 216 in 3-D: morphology of a TP-AGB star envelope
• Binary Central Stars of Planetary Nebulae Identified With Kepler/K2
• Planetary nebulae that cannot be explained by binary systems
• Inclined jets inside a common envelope of a triple stellar system
• Shaping planetary nebulae with jets in inclined triple stellar systems
• On the triple-star origin of the planetary nebula Sh 2-71
• An outburst powered by the merging of two stars inside the envelope of a giant
• When Nature Tries to Trick Us
• Two's company, three's a crowd: SALT reveals the likely triple nature of the nucleus of the extreme abundance discrepancy factor planetary nebula Sp 3
• Central Stars of Planetary Nebulae
• A detailed study of the barium central star of the planetary nebula Abell 70
• A Mysterious Ring in Dark Space?