1 Introduction

M2-42 (=PNG008.2$ -$04.8 = Hen2-393 = VV177 = Sa2-331) was discovered as a planetary nebula (PN) by Minkowski (1947). The H$ \alpha $ image, Fig. 1 (top panel), obtained from the AAO/UKST SuperCOSMOS H$ \alpha $ Sky Survey (SHS; Parker et al., 2005) revealed an elliptical morphological structure with a clear extension to the north east, suggesting the presence of bipolar outflows. The long-slit data from the San Pedro Mártir kinematic catalogue (SPM; López et al., 2012) disclosed the presence of a dense torus-like component and collimated bipolar outflows (Akras & López, 2012). The JHK$ _{\rm s}$ image, Fig. 1 (bottom panel), obtained from the VISTA variables in the Vía Láctea Survey (VVV; Saito et al., 2012) also shows the presence of a compact dusty torus embedded in the main shell.

Wang & Liu (2007) carried out plasma diagnostics and abundance analysis of M2-42 using deep long-slit optical spectroscopy. They derived a mean electron density of $ N_{\rm e}\simeq3 \times 10^3$ cm$ ^{-3}$, and an electron temperature of $ T_{\rm e}$=9350 K from the [NII] line ratio, which is consistent with those of other PNe (see e.g. Kingsburgh & Barlow, 1994). The oxygen abundance of O/H =  $ 5.62 \times 10^{-4}$ derived by Wang & Liu (2007) is slightly above the solar metallicity, while N/O=0.32 corresponds to a non-Type I PN (based on N/O $ < 0.8$; Kingsburgh & Barlow, 1994).

The central star of M2-42 depicts weak emission-line star characteristics (wels defined by Tylenda et al., 1993) dominated by nitrogen and helium (DePew et al., 2011). The nebular spectrum of moderate excitation, $ I$(5007$ )=807$ on a scale where $ I$(H $ \beta)=100$ (Wang & Liu, 2007), is related to an excitation class of 3.6 (Dopita & Meatheringham, 1990), and a stellar temperature of 74kK (Dopita & Meatheringham, 1991) or 69kK (Reid & Parker, 2010). Based on the Energy-Balance method, Preite-Martinez et al. (1989) estimated a stellar temperature of 74.9 kK. According to Tylenda et al. (1991a), the central star has a B magnitude of 18.2. Using the HI Zanstra method, Tylenda et al. (1991b) derived a stellar temperature of 56 kK and a luminosity of $ \log L/$L $ _{\bigodot} = 2.87$, which correspond to a current core mass of 0.62M $ _{\bigodot}$.

Based on its angular diameter and radio brightness (6 cm), Acker et al. (1991) suggested that M2-42 is most likely located in the Galactic bulge. Cahn et al. (1992) estimated a distance of 8754 pc to the PN, which places it near to the Galactic center. The most recent distance estimation by Stanghellini et al. (2008) yielded a distance of 9444 pc. Moreover, we estimate a distance of 7400 $ ^{+570}_{-550}$ from the H$ \alpha $ surface brightness-radius relation for a sample of 332 PNe (Frew et al., 2015), total flux value of $ \log F($H $ \alpha)= −11.39$ ergcm$ ^{-2}$s$ ^{-1}$ (Frew et al., 2013), $ c$(H$ \beta$)$ =0.99$ (Wang & Liu, 2007), and angular radius of 2 arcsec (Stanghellini et al., 2008). Therefore, it could be a Galactic Bulge PN (GBPN).

In this paper, we present our integral field spectroscopy of M2-42, from which we determine ionization and kinematic properties of the nebula and its collimated outflows. In Section 2, we present the observations together with the physical and chemical conditions, stellar characteristics, and kinematic results derived from our data. Section 3 describes the morpho-kinematic model of M2-42 and, finally, in Section 4 we draw our conclusion.

Figure 1: Top panel: The H$ \alpha $ image obtained from the SHS (Parker et al., 2005) with the morphological features labeled. The rectangle shows the $ 25\hbox {$^{\prime \prime }$}\times 38\hbox {$^{\prime \prime }$}$ WiFeS field of view observed using the ANU 2.3-m telescope in 2010 April. The image scale is shown by a solid line. North is up and east is toward the left-hand side. Bottom panel: The JHK$ _{\rm s}$ image obtained from the VVV Survey (Saito et al., 2012) with the compact dusty torus labeled. The red, green, and blue colors are assigned to the K$ _{\rm s}$, H, and J, respectively.
\includegraphics[width=2.4in]{figures/fig1_m2-42a.eps}
\includegraphics[width=2.4in]{figures/fig1_m2-42b.eps}

Ashkbiz Danehkar
2018-03-28