Expansion velocities and core masses of bright planetary nebulae in the Virgo cluster

TL;DR

This study measures expansion velocities and core masses of planetary nebulae in the Virgo cluster, revealing high central star masses and short observable lifetimes, indicating dense, compact nebulae in a distant galaxy cluster.

Contribution

It provides the first measurements of expansion velocities and core masses of PNs in the Virgo cluster, linking nebular properties to stellar evolution in a dense galaxy environment.

Findings

Average expansion velocity is 16.5 km/s.

Central star masses are at least 0.6 solar masses.

PN observable lifetime is less than 2000 years.

Abstract

The line-of-sight velocities and [OIII] 5007 AA expansion velocities are measured for 11 planetary nebulae (PNs) in the Virgo cluster core, at 15 Mpc distance, with the FLAMES spectrograph on the ESO VLT. These PNs are located about halfway between the two giant ellipticals M87 and M86. From the [OIII] 5007 AA line profile widths, the average half-width at half maximum expansion velocity for this sample of 11 PNs is v_HWHM = 16.5 km/s (RMS=2.6 km/s). We use the PN subsample bound to M87 to remove the distance uncertainties, and the resulting [OIII] 5007 AA luminosities to derive the central star masses. We find these masses to be at least 0.6 M_sun and obtain PN observable life times t_PN < 2000 yrs, which imply that the bright PNs detected in the Virgo cluster core are compact, high density nebulae. We finally discuss several scenarios for explaining the high central star masses in these bright M87 halo PNs.