The Secret Lives of Cepheids: Evolution, Mass Loss, and Ultraviolet Emission of the Long-Period Classical Cepheid $l$ Carinae

Abstract

The classical Cepheid $l$ Carinae is an essential calibrator of the Cepheid Leavitt Law as a rare long-period Galactic Cepheid. Understanding the properties of this star will also constrain the physics and evolution of massive ($M\ge 8$ $M_{\odot }$) Cepheids. The challenge, however, is precisely measuring the star's pulsation period and its rate of period change. The former is important for calibrating the Leavitt Law and the latter for stellar evolution modeling. In this work, we combine previous time-series observations spanning more than a century with new observations to remeasure the pulsation period and compute the rate of period change. We compare our new rate of period change with stellar evolution models to measure the properties of $l$ Car, but find models and observations are, at best, marginally consistent. The results imply that $l$ Car does not have significantly enhanced mass-loss rates like that measured for $\delta$ Cephei. We find that the mass of $l$ Car is about 8 - 10 $M_{\odot }$. We present Hubble Space Telescope COS observations that also differ from measurements for $\delta$ Cep, and $\beta$ Dor. These measurements further add to the challenge of understanding the physics of Cepheids, but do hint at the possible relation between enhanced mass loss and ultraviolet emission, perhaps both due to the strength of shocks propagating in the atmospheres of Cepheids.

arXiv comment11 pages, 6 figures, 1 table, ApJ accepted

References in corpus (40)

• Pre-Supernova Evolution of Massive Single and Binary Stars
• The evolution of rotating stars
• Carnegie Hubble Program: A Mid-Infrared Calibration of the Hubble Constant
• Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations
• On the evolution of rapidly rotating massive white dwarfs towards supernovae or collapses
• Yellow supergiants as supernova progenitors: an indication of strong mass loss for red supergiants?
• Classical Cepheid Pulsation Models. III. The Predictable Scenario
• Rate of Period Change as a Diagnostic of Cepheid Properties
• Pulsation and evolutionary masses of classical Cepheids. I. Milky Way variables
• On the Enhancement of Mass Loss in Cepheids Due to Radial Pulsation
• On the effect of rotation on populations of classical Cepheids I. Predictions at solar metallicity
• The PL calibration for Milky Way Cepheids and its implications for the distance scale
• The Cepheid mass discrepancy and pulsation-driven mass loss
• Stellar evolution through the ages: period variations in galactic RRab stars as derived from the GEOS database and TAROT telescopes
• Cepheid distances from the SpectroPhoto-Interferometry of Pulsating Stars (SPIPS) - Application to the prototypes delta Cep and eta Aql
• Period and light curve fluctuations of the Kepler Cepheid V1154 Cyg
• An Infrared Nebula Associated with Delta Cephei: Evidence of Mass Loss?
• Observational calibration of the projection factor of Cepheids. II. Application to nine Cepheids with HST/FGS parallax measurements
• The circumstellar envelopes of the Cepheids L Car and RS Pup - Comparative study in the infrared with Spitzer, VLT/VISIR and VLTI/MIDI
• Double bow shocks around young, runaway red supergiants: application to Betelgeuse
• A Classical Cepheid in a LMC eclipsing binary: evidence of shortcomings in current stellar evolutionary models?
• New Evidence for Mass Loss from delta Cephei from HI 21-cm Line Observations
• Observations of Cepheids with the MOST satellite: Contrast between Pulsation Modes
• Investigating Cepheid $\ell$ Carinae's Cycle-to-cycle Variations via Contemporaneous Velocimetry and Interferometry
• On the Blue Loops of Intermediate-Mass Stars
• Multidimensional realistic modelling of Cepheid-like variables. I: Extensions of the ANTARES code
• The angular size of the Cepheid L Car: a comparison of the interferometric and surface brightness techniques
• Classical Cepheids Require Enhanced Mass Loss
• The period change of the Cepheid Polaris suggests enhanced mass loss
• The Secret Lives of Cepheids: Evolutionary Changes and Pulsation-Induced Shock Heating in the Prototype Classical Cepheid δ Cep
• Convection, granulation and period jitter in classical Cepheids
• Multidimensional realistic modelling of Cepheid-like variables-II: Analysis of a Cepheid model
• On the stability of bow shocks generated by red supergiants: the case of IRC-10414
• Evolutionary status of Polaris
• On the Enhancement of Mass Loss in Cepheids Due to Radial Pulsation. II. The Effect of Metallicity
• Resolved Companions of Cepheids: Testing the Candidates with X-Ray Observations
• Convective quenching of stellar pulsations
• Revisiting the fundamental properties of Cepheid Polaris using detailed stellar evolution models
• Period change and stellar evolution of $\beta$ Cephei stars
• X-Ray, UV and Optical Observations of Classical Cepheids: New Insights into Cepheid Evolution, and the Heating and Dynamics of Their Atmospheres

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• Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2 - I. Binarity from proper motion anomaly
• Discovery of Cycle-to-cycle Modulated Spectral Line Variability and Velocity Gradients in Long-period Cepheids
• High-precision distance measurements with classical pulsating stars
• The Secret Lives of Cepheids: $\delta$ Cep -- the Prototype of a New Class of Pulsating X-ray Variable Stars
• The VMC survey - XXIII. Model fitting of light and radial velocity curves of Small Magellanic Cloud classical Cepheids
• Kinetic Tomography. II. A second method for mapping the velocity field of the Milky Way Interstellar Medium and a comparison with spiral structure models
• HI Intensity Mapping for Clustering-Based Redshift Estimation
• Mid-infrared circumstellar emission of the long-period Cepheid l Carinae resolved with VLTI/MATISSE
• CRIRES high-resolution infrared spectroscopy of the long-period Cepheid l Car
• One of Everything: The Breakthrough Listen Exotica Catalog
• Period Variations for the Cepheid VZ Cyg
• First Detection of Radio Emission Associated with a Classical Cepheid