V363 Cas: a new lithium rich Galactic Cepheid

Abstract

Classical Cepheids (DCEPs) are important astrophysical objects not only as standard candles in the determination of the cosmic distance ladder, but also as a testbed for the stellar evolution theory, thanks to the strict connection between their pulsation [period(s), amplitudes] and stellar (luminosity, mass, effective temperature, metallicity) parameters. We aim at unveiling the nature of the Galactic DCEP V363 Cas and other DCEPs showing cosmic abundances of lithium in their atmospheres. We have collected three epochs high-resolution spectroscopy for V363 Cas with HARPS-N@TNG. Accurate stellar parameters: effective temperatures, gravities, micro-turbulences, radial velocities, and metal abundances were measured for this star. We detected a lithium abundance of A(Li)=2.86+-0.10 dex, along with iron, carbon and oxygen abundances of [Fe/H]=-0.30+-0.12 dex, [C/H]=-0.06+-0.15 dex and [O/H]=0.00+-0.12 dex. V363 Cas is the fifth among the Milky Way DCEPs to exhibit a Li-rich feature. An analysis of historical time-series spanning a hundred year interval shows that the period of V363 Cas is increasing, with a sharp acceleration after HJD=2453000. This is a clear hint of first crossing of the instability strip. Our results favour the scenario in which the five Galactic Li-rich DCEPs are first-crossing the instability strip having had slowly-rotating progenitors during their main sequence phase.

arXiv commentAccepted on Astronomy and Astrophysics (Letter). 5 Pages

References in corpus (21)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Correcting for the Effects of Interstellar Extinction
• Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones
• The evolution of rotating stars
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• The ASAS-SN Catalog of Variable Stars I: The Serendipitous Survey
• Stellar and substellar companions of nearby stars from Gaia DR2 - Binarity from proper motion anomaly
• A Bitter Pill: The Primordial Lithium Problem Worsens
• A Stellar Rotation Census of B Stars: from ZAMS to TAMS
• The Distribution of the Elements in the Galactic Disk III. A Reconsideration of Cepheids from l = 30 to 250 Degrees
• The influence of chemical composition on the properties of Cepheid stars. II-The iron content
• Rate of Period Change as a Diagnostic of Cepheid Properties
• The first INTEGRAL-OMC catalogue of optically variable sources
• RR Lyrae variables: visual and infrared luminosities, intrinsic colours, and kinematics
• The Cepheid period -- luminosity -- metallicity relation based on Gaia DR2 data
• Stellar evolution through the ages: period variations in galactic RRab stars as derived from the GEOS database and TAROT telescopes
• Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2 -- II. Resolved common proper motion pairs
• Evidence for Galactic disc RR~Lyrae stars in the Solar neighbourhood
• An extended theoretical scenario for Classical Cepheids. I. Modeling Galactic Cepheids in the Gaia photometric system
• C, N, O, and Na Abundances of Cepheid Variables: Implications on the Mixing Process in the Envelope
• Analysing the spectral energy distributions of Galactic classical Cepheids

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• Cepheid Metallicity in the Leavitt Law (C- MetaLL) survey: II.High-resolution spectroscopy of the most metal poor Galactic Cepheids
• Period Change Rates in Large Magellanic Cloud Cepheids Revisited
• HD344787: a true Polaris analogue?
• Cepheid Metallicity in the Leavitt Law (C-MetaLL) survey: IX. Metallicity dependence of Period-Wesenheit relations based on a homogeneous spectroscopic sample