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 B. Williams}, journal={The Astrophysical Journal Letters}, 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…
29 Citations
Pulsation Period Change & Classical Cepheids: Probing the Details of Stellar Evolution
- PhysicsProceedings of the International Astronomical Union
- 2014
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…
Revisiting the fundamental properties of the Cepheid Polaris using detailed stellar evolution models
- Physics
- 2014
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…
THE SECRET LIVES OF CEPHEIDS: EVOLUTION, MASS-LOSS, AND ULTRAVIOLET EMISSION OF THE LONG-PERIOD CLASSICAL CEPHEID
- Physics
- 2016
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…
Observations of Cepheids with the MOST satellite: contrast between pulsation modes
- Physics
- 2015
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
- Physics
- 2014
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…
The Pulsation Mode of the Cepheid Polaris
- Physics
- 2013
A previously derived photometric parallax of 10.10 ± 0.20 mas, d = 99 ± 2 pc, is confirmed for Polaris by a spectroscopic parallax derived using line ratios in high dispersion spectra for the…
A SEARCH FOR MASS LOSS ON THE CEPHEID INSTABILITY STRIP USING H i 21 cm LINE OBSERVATIONS
- Physics
- 2016
We present the results of a search for H i 21 cm line emission from the circumstellar environments of four Galactic Cepheids (RS Pup, X Cyg, ζ Gem, and T Mon) based on observations with the Karl G.…
The strange evolution of the Large Magellanic Cloud Cepheid OGLE-LMC-CEP1812
- Physics
- 2015
Classical Cepheids are key probes of both stellar astrophysics and cosmology as standard candles and pulsating variable stars. It is important to understand Cepheids in unprecedented detail in…
Evolving pulsation of the slowly rotating magnetic β Cep star ξ1 CMa
- PhysicsMonthly Notices of the Royal Astronomical Society
- 2020
Recent BRITE-Constellation space photometry of the slowly rotating, magnetic β Cep pulsator ξ1 CMa permits a new analysis of its pulsation properties. Analysis of the two-colour BRITE data reveals…
Asteroseismology of the Double-mode High-amplitude δ Scuti Star VX Hydrae
- PhysicsThe Astrophysical Journal
- 2018
Bi-site time-series photometric and high-resolution spectroscopic observations were made for the double-mode high-amplitude δ Scuti star VX Hya. The fundamental frequency f0 = 4.4763 c days−1, the…
References
SHOWING 1-10 OF 24 REFERENCES
Cepheid Mass Loss and the Pulsation-Evolutionary Mass Discrepancy
- Physics
- 2008
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…
Rate of Period Change as a Diagnostic of Cepheid Properties
- Physics
- 2006
The rate of period change P˙ for a Cepheid is shown to be a parameter that is capable of indicating the instability‐strip crossing mode for individual objects and, in conjunction with light…
The Cepheid mass discrepancy and pulsation-driven mass loss
- Physics
- 2011
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
- Physics
- 2000
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
- Physics
- 2008
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
- Physics
- 2000
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…
Extended envelopes around Galactic Cepheids. II. Polaris and delta Cephei from near-infrared interfe
- Physics
- 2006
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…
TESTING MASS LOSS IN LARGE MAGELLANIC CLOUD CEPHEIDS USING INFRARED AND OPTICAL OBSERVATIONS
- Physics
- 2009
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…
Period changes of Cepheid variables
- Physics
- 1983
Secular period changes of one hundred northern Cepheids are investigated with the help of O−C diagrams. With the classical Cepheids the rate of observed period changes is in good agreement with that…
Presupernova Evolution of Rotating Massive Stars. I. Numerical Method and Evolution of the Internal Stellar Structure
- Physics
- 2000
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…