We present [ OIII ] 500.7nm and H \alpha + [ NII ] images and long-slit , high resolution echelle spectra in the same spectral regions of Sa2–237 , a possible bipolar planetary nebula .
The image shows a bipolar nebula of about 34″extent , with a narrow waist , and showing strong point symmetry about the central object , indicating it ’ s likely binary nature .
The long slit spectra were taken over the long axis of the nebula , and show a distinct “ eight ” shaped pattern in the velocity–space plot , and a maximum projected outflow velocity of V _ { exp } = 106 km \cdot s ^ { -1 } , both typical of expanding bipolar planetary nebulae .
By model fitting the shape and spectrum of the nebula simultaneously , we derive the inclination of the long axis to be 70 ^ { o } , and the maximum space velocity of expansion to be \leq 308 km \cdot s ^ { -1 } .
Due to asymmetries in the velocities we adopt a new value for the system ’ s heliocentric radial velocity of -30km.s ^ { -1 } .
We use the IRAS & 21cm radio fluxes , the energy distribution , and the projected size of Sa2-237 to estimate it ’ s distance to be 2.1 \pm 0.37kpc .
At this distance Sa2-237 has a luminosity of 340 L _ { \sun } , a size of 0.37pc , and – assuming constant expansion velocity – a nebular age of 624 years .
The above radial velocity & distance place Sa2–237 in the disk of the Galaxy at z=255pc , albeit with somewhat peculiar kinematics .