A new look inside Planetary Nebula LoTr 5: A long-period binary with hints of a possible third component

Abstract

LoTr 5 is a planetary nebula with an unusual long-period binary central star. As far as we know, the pair consists of a rapidly rotating G-type star and a hot star, which is responsible for the ionization of the nebula. The rotation period of the G-type star is 5.95 days and the orbital period of the binary is now known to be $\sim$2700 days, one of the longest in central star of planetary nebulae. The spectrum of the G central star shows a complex H$\alpha$ double-peaked profile which varies with very short time scales, also reported in other central stars of planetary nebulae and whose origin is still unknown. We present new radial velocity observations of the central star which allow us to confirm the orbital period for the long-period binary and discuss the possibility of a third component in the system at $\sim$129 days to the G star. This is complemented with the analysis of archival light curves from SuperWASP, ASAS and OMC. From the spectral fitting of the G-type star, we obtain a effective temperature of $T_{\mathrm{eff}}$ = 5410$\pm$250 K and surface gravity of $\log g$ = 2.7$\pm$0.5, consistent with both giant and subgiant stars. We also present a detailed analysis of the H$\alpha$ double-peaked profile and conclude that it does not present correlation with the rotation period and that the presence of an accretion disk via Roche lobe overflow is unlikely.

12 pages, 12 figures, accepted for publication in MNRAS

References in corpus (9)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• The first WASP public data release
• 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)
• SOPHIE velocimetry of Kepler transit candidates VI. An additional companion in the KOI-13 system
• Distinguishing between symbiotic stars and planetary nebulae
• Kepler-447b: a hot-Jupiter with an extremely grazing transit
• Spectroscopy of the symbiotic star CH Cygni from 1996 to 2007

Cited by in corpus (2)

• Surface magnetic activity of the fast-rotating G5-giant IN Comae, central star of the faint planetary nebula LoTr 5
• Spectral analysis of the barium central star of the planetary nebula Hen 2-39