The evolutionary nature of RV Tauri stars in the SMC and LMC

Abstract

Based on their stellar parameters and the presence of a mid-IR excess due to circumstellar dust, RV Tauri stars have been classified as post-AGB stars. Our recent studies, however, reveal diverse SEDs among RV Tauri stars, suggesting they may occupy other evolutionary channels as well. The aim of this paper is to present the diverse SED characteristics of RV Tauri stars and investigate their evolutionary nature as a function of their SEDs. We carried out a systematic study of RV Tauri stars in the SMC and LMC because of their known distances and hence luminosities. Their SEDs were classified in three groups: dusty (disc-type), non-dusty (non-IR) and uncertain. A period-luminosity- colour (PLC) relation was calibrated. The luminosities from the PLC were complemented with the ones found using their SEDs and the stars were placed on the HR-diagram. The four main results from this study are: 1) RV Tauri stars with a clear IR-excess have disc-type SEDs, which indicates that the dust is trapped in a stable disc. Given the strong link between disc-type SEDs and binarity in the Galaxy, we postulate that these are binaries as well. These cover a range of luminosities and we argue that the more luminous ones are post-AGB stars while the lower luminosity ones are likely post-Red Giant Branch (post-RGB) stars. 2) Two of these objects have variable mean brightness with periods of 916 and 850 days, respectively, caused by variable extinction during orbital motion. 3) The non-dusty RV Tauri stars and the objects with an uncertain SED evolve such that the circumstellar dust has dispersed. If they are single stars, they are post-AGB objects of low initial mass ($<$ 1.25 M${}_{\odot }$), while if they are binaries, the low-luminosity part of the sample are likely post-RGB stars. 4) We find that RV Tauri stars with dust are on average more luminous than the rest of the sample.

32 Pages, Accepted to be published in A&A

References in corpus (16)

• An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
• New models for the evolution of Post-Asymptotic Giant Branch stars and Central Stars of Planetary Nebulae
• Keplerian discs around post-AGB stars: a common phenomenon?
• New Optical Reddening Maps of the Large and Small Magellanic Clouds
• Structure of Herbig AeBe disks at the milliarcsecond scale A statistical survey in the H band using PIONIER-VLTI
• Optically visible post-AGB/RGB stars and young stellar objects in the Small Magellanic Cloud: candidate selection, spectral energy distributions and spectroscopic examination
• A newly discovered stellar type: dusty post-red giant branch stars in the Magellanic Clouds
• The VMC Survey. XIII. Type II Cepheids in the Large Magellanic Cloud
• Imaging the dust sublimation front of a circumbinary disk
• Establishing binarity amongst Galactic RV Tauri stars with a disc
• Defining the instability strip of pulsating post-AGB binary stars from ASAS and NSVS photometry
• A mid-IR interferometric survey with MIDI/VLTI: resolving the second-generation protoplanetary disks around post-AGB binaries
• On the Blue Loops of Intermediate-Mass Stars
• The period-luminosity and period-radius relations of Type II and anomalous Cepheids
• AGB nucleosynthesis in the Large Magellanic Cloud. Detailed abundance analysis of the RV Tauri star MACHO47.2496.8
• Luminosities and infrared excess in Type II and anomalous Cepheids in the Large and Small Magellanic Clouds

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• Common Envelope Mass Ejection in Evolved Stars: Modeling the Dust Emission from post-RGB stars in the LMC
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