Spectroscopic Observations of \delta Sco Through the 2011 Periastron Passage

TL;DR

This paper reports spectroscopic observations of elta Sco during its 2011 periastron, finding no tidal disturbance to pulsations or mass ejection, but evidence of disk disturbance propagating inward post-periastron.

Contribution

It provides the first coordinated spectroscopic data of elta Sco during periastron, revealing disk disturbances without tidal triggering of pulsations or mass ejection.

Findings

No tidally induced disturbance to eta Cephei pulsation mode.

No tidally triggered mass ejection at periastron.

Disk disturbance propagates inward after periastron.

Abstract

We present prelimiary results from a coordinated spectroscopic campaign in 2011, centered on the \delta Sco periastron passage in July. Data have mostly been obtained with the FEROS/2.2 m at La Silla and ESPaDOnS/CFHT at Mauna Kea echelle instruments. Main results include the absence of tidally induced disturbance to the main \beta Cephei pulsation mode and the absence of tidally triggered mass-ejection at time of periastron proper. The observed (as far as yet analyzed) variations are compatible with the picture of a disk that is disturbed on its outer radius, with the disturbance propagating inwards after the periastron.