THE PERIOD CHANGE OF THE CEPHEID POLARIS SUGGESTS ENHANCED MASS LOSS

@article{Neilson2012THEPC,
  title={THE PERIOD CHANGE OF THE CEPHEID POLARIS SUGGESTS ENHANCED MASS LOSS},
  author={Hilding R. Neilson and Scott G. Engle and Edward F. Guinan and Norbert Langer and Richard P. Wasatonic and David Brian Williams},
  journal={The Astrophysical Journal},
  year={2012},
  volume={745}
}
Polaris is one of the most observed stars in the night sky, with recorded observations spanning more than 200 years. From these observations, one can study the real-time evolution of Polaris via the secular rate of change of the pulsation period. However, the measurements of the rate of period change do not agree with predictions from state-of-the-art stellar evolution models. We show that this may imply that Polaris is currently losing mass at a rate of yr–1 based on the difference between… 

Figures from this paper

Pulsation Period Change & Classical Cepheids: Probing the Details of Stellar Evolution
Abstract Measurements of secular period change probe real-time stellar evolution of classical Cepheids making these measurements powerful constraints for stellar evolution models, especially when
CLASSICAL CEPHEIDS REQUIRE ENHANCED MASS LOSS
Measurements of rates of period change of Classical Cepheids probe stellar physics and evolution. Additionally, better understanding of Cepheid structure and evolution provides greater insight into
Revisiting the fundamental properties of the Cepheid Polaris using detailed stellar evolution models
Polaris the Cepheid has been observed for centuries, presenting surprises and changing our view of Cepheids and stellar astrophysics, in general. Specifically, understanding Polaris helps anchor the
Evolutionary status of Polaris
Hydrodynamic models of short--period Cepheids were computed to determine the pulsation period as a function of evolutionary time during the first and third crossings of the instability strip. The
THE SECRET LIVES OF CEPHEIDS: EVOLUTION, MASS-LOSS, AND ULTRAVIOLET EMISSION OF THE LONG-PERIOD CLASSICAL CEPHEID*
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
Rotation, Convective Core Overshooting, and Period Changes in Classical Cepheid Stellar Evolution Models
Classical Cepheids are powerful probes of both stellar evolution and near-field cosmology thanks to their high luminosities, pulsations, and that they follow the Leavitt (Period-Luminosity) Law.
Evolving pulsation of the slowly rotating magnetic β Cep star ξ1 CMa
We report BRITE-Constellation photometry of the beta Cep pulsator xi 1 CMa. Analysis of these data reveals a single pulsation period of 0.2095781(3) d, along with its first and second harmonics. We
Period Change and Stellar Evolution of β Cephei Stars
The $\beta$ Cephei stars represent an important class of massive star pulsators probing the evolution of B-type stars and the transition from main sequence to hydrogen-shell burning evolution. By
Observations of Cepheids with the MOST satellite: contrast between pulsation modes
The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode
Convection, granulation, and period jitter in classical Cepheids
Analyses of recent observations of the sole classical Cepheid in the Kepler field, V1154 Cygni, found random changes of about 30 min in the pulsation period. These period changes challenge standard
...
1
2
3
...

References

SHOWING 1-10 OF 27 REFERENCES
Cepheid Mass loss and the Pulsation-Evolutionary Mass Discrepancy
I investigate the discrepancy between the evolution and pulsation masses for Cepheid variables. A number of recent works have proposed that noncanonical mass loss can account for the mass
The period changes of polaris
The evolutionary changes in pulsation period for the Cepheid Polaris are reinvestigated using archival observational material (radial velocities, photometry, and eye observations) over the interval
On the Enhancement of Mass Loss in Cepheids Due to Radial Pulsation
An analytical derivation is presented for computing mass-loss rates of Cepheids by using the method of Castor, Abbott, and Klein modified to include a term for momentum input from pulsation and
The Cepheid mass discrepancy and pulsation-driven mass loss
Context. A longstanding challenge for understanding classical Cepheids is the Cepheid mass discrepancy, where theoretical mass estimates using stellar evolution and stellar pulsation calculations
Polaris: Amplitude, Period Change, and Companions
Polaris has presented us with the rare phenomenon of a Cepheid with a pulsation amplitude that has decreased over the last 50 yr. In this study we have used this property to see whether the amplitude
The period and amplitude changes of Polaris (α UMi) from 2003 to 2007 measured with SMEI
We present an analysis of 4.5 years of high precision (0.1%) space-based photometric measurements of the Cepheid variable Polaris, obtained by the broad band Solar Mass Ejection Imager (SMEI)
Classical Cepheid Pulsation Models. III. The Predictable Scenario
Within the current uncertainties in the treatment of the coupling between pulsation and convection, the limiting amplitude, nonlinear, convective models appear the only viable approach for providing
Testing Mass Loss in Large Magellanic Cloud Cepheids Using Infrared and Optical Observations
It has been claimed that period-luminosity (P-L) relations derived from infrared observations of Large Magellanic Cloud (LMC) Cepheids are less dependent on the metallicity of the Cepheids. In this
Extended envelopes around Galactic Cepheids. II. Polaris and delta Cephei from near-infrared interfe
We present the results of long-baseline interferometric observations of the classical Cepheids Polaris and δ  Cep in the near infrared K'  band (1.9-2.3  μ m), using the FLUOR instrument of the CHARA
Presupernova Evolution of Rotating Massive Stars. I. Numerical Method and Evolution of the Internal Stellar Structure
The evolution of rotating stars with zero-age main-sequence (ZAMS) masses in the range 8-25 M☉ is followed through all stages of stable evolution. The initial angular momentum is chosen such that the
...
1
2
3
...