1 Introduction

The planetary nebula (PN) Th2-A (=PN G306.4$ -$00.6) was classified by Kromov & Kohoutek (1968) under the ring-shaped objects. This morphology is also visible in the H$ \alpha $ image taken by Górny et al. (1999). The abundance analysis of Th2-A yielded He/H = 0.09 and N/O = 0.40 (Kingsburgh & Barlow, 1994), and He/H = 0.13 and N/O = 0.49 (Henry et al., 2004). The oxygen abundance was found to be close to the solar metallicity (O/H =  $ 4.67\times10^{-4}$; Kingsburgh & Barlow, 1994). The nebular HeII $ I$(4686$ )/I$(H $ \beta)=0.50$, measured by Kingsburgh & Barlow (1994) corresponds to a relatively high-excitation nebula. This PN has a moderate density of $ N_{\rm e}$(SII) = 1220cm$ ^{-3}$ (Kingsburgh & Barlow, 1994), which could be associated with a relatively hot central star (CSPN) based on the evolutionary radiation-hydrodynamic models (Perinotto et al., 2004).

This PN is indeed ionized by a very hot star classified as [WO3] $ {}_{\rm pec}$ (Weidmann et al., 2008). Previously, Acker & Neiner (2003) defined the [WO] $ {}_{\rm pec}$ subclass as those with a peculiar CIV 5805Å full width at half maximum (FWHM), much wider than typical [WO]. Similarly, Weidmann et al. (2008) identified the CSPN Th2-A as type [WO] $ {}_{\rm pec}$, belonging to those with peculiar CIV-5801/12 doublet. According to the transformation given by Dopita & Meatheringham (1991), the strength of HeII $ \lambda $4686 relative to H$ \beta$ describes a stellar temperature of $ T_{\rm eff}=158$kK. However, the HeII and [OIII] emission lines can also correspond to $ T_{\rm eff}=291$kK based on the method introduced by Reid & Parker (2010).

Th2-A was found to contain a possible binary system (Ciardullo et al., 1999). One component of the binary is a CSPN, and another component is a visual late-type star separated by $ 1$$ \mbox{$.\!\!^{\prime\prime}$}$$ 4$ (Weidmann et al., 2008). However, the resolved companion could be a possible superposition. Previously, Kerber et al. (2003) described Th2-A as PN with a well defined photometric center. Although there are no detailed studies on the visual companion spectra, Weidmann et al. (2008) identified broad and intense CIV and OIV emission lines in the CSPN spectra, which made it one of the rare [WO] $ {}_{\rm pec}$ stars. Notwithstanding, if the nearby visual star is indeed a binary companion of the CSPN, it unlikely contributes to the formation of the fast stellar winds identified in its spectra since its separation is 3500 AU at the distance of 2.5kpc determined by Stanghellini & Haywood (2010).

In this paper we present integral field spectroscopic mapping of Th2-A, from which we derive a morpho-kinematic model of this object. Currently, there are no previous morpho-kinematic studies on this object in the literature. In Section 2, we describe the details of the observation. In Section 3, we discuss the results. Section 4 presents the morpho-kinematic model of Th2-A. Finally, we finish with our conclusions in Section 5.

Ashkbiz Danehkar
2018-03-27