The orbital kinematics of η Carinae over three periastra with a possible detection of the elusive secondary's motion. Issue 4 (6th January 2023)

• Record Type: Journal Article
• Authors: Strawn, Emily; Richardson, Noel D; Moffat, Anthony F J; Ibrahim, Nour; Lane, Alexis; Pickett, Connor; Chené, André-Nicolas; Corcoran, Michael F; Damineli, Augusto; Gull, Theodore R; Hillier, D John; Morris, Patrick; Pablo, Herbert; Thomas, Joshua D; Stevens, Ian R; Teodoro, Mairan; Weigelt, Gerd
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 519:Issue 4(2023)
• Page Start: 5882
• Page End: 5892
• Publication Date: 2023-01-06
• Subjects: techniques: spectroscopic -- binaries: spectroscopic -- stars: individual: η Carinae -- stars: massive -- stars: variables: S Doradus -- stars: winds, outflows; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stad018
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: The binary η Carinae is the closest example of a very massive star, which may have formed through a merger during its Great Eruption in the mid-19th century. We aimed to confirm and improve the kinematics using a spectroscopic data set taken with the Cerro Tololo Inter-American Observatory 1.5-m telescope over the time period of 2008–2020, covering three periastron passages of the highly eccentric orbit. We measure line variability of H α and H β, where the radial velocity and orbital kinematics of the primary star were measured from the H β emission line using a bisector method. At phases away from periastron, we observed the He ii 4686 emission moving opposite the primary star, consistent with a possible Wolf–Rayet companion, although with a seemingly narrow emission line. This could represent the first detection of emission from the companion.