Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The dynamical mass of a classical Cepheid variable star in an eclipsing binary system

Nature volume 468, pages 542–544 (2010)Cite this article

Subjects

Abstract

Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiants—it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses derived from stellar evolution theory: this is the Cepheid mass discrepancy problem1,2, for which a solution is missing3,4,5. An independent, accurate dynamical mass determination for a classical Cepheid variable star (as opposed to type-II Cepheids, low-mass stars with a very different evolutionary history) in a binary system is needed in order to determine which is correct. The accuracy of previous efforts to establish a dynamical Cepheid mass from Galactic single-lined non-eclipsing binaries was typically about 15–30% (refs 6, 7), which is not good enough to resolve the mass discrepancy problem. In spite of many observational efforts8,9, no firm detection of a classical Cepheid in an eclipsing double-lined binary has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined eclipsing binary in the Large Magellanic Cloud. We determine the mass to a precision of 1% and show that it agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Figure 1: The procedure adopted to separate pulsational and orbital motion of the Cepheid.
Figure 2: Orbital motion of the two binary components, and the pulsational motion of the Cepheid variable in the binary system.
Figure 3: Change of brightness of the binary system caused by the mutual eclipses, and the intrinsic change of the brightness of the Cepheid component caused by its pulsations.
Figure 4: The period and brightness of the Cepheid component of our system confirm that it is a classical Cepheid.

References

  1. Christy, R. F. The theory of Cepheid variability. Q. J. R. Astron. Soc. 9, 13–39 (1968)

    ADS  Google Scholar 

  2. Stobie, R. S. Cepheid pulsation–III. Models fitted to a new mass-luminosity relation. Mon. Not. R. Astron. Soc. 144, 511–535 (1969)

    Article  ADS  Google Scholar 

  3. Cox, A. N. The masses of Cepheids. Annu. Rev. Astron. Astrophys. 18, 15–41 (1980)

    Article  ADS  Google Scholar 

  4. Gieren, W. Towards a reconciliation of Cepheid masses. Astron. Astrophys. 225, 381–390 (1989)

    ADS  Google Scholar 

  5. Bono, G., Gieren, W., Marconi, M., Fouquè, P. & Caputo, F. Improving the mass determination of Galactic Cepheids. Astrophys. J. 563, 319–324 (2001)

    Article  ADS  Google Scholar 

  6. Evans, N. R. et al. Direct detection of the close companion of Polaris with the Hubble Space Telescope. Astron. J. 136, 1137–1146 (2008)

    Article  ADS  CAS  Google Scholar 

  7. Evans, N. R. in Stellar Pulsation: Challenges for Theory and Observation (eds Guzik, J. A. & Bradley, P. A.) 69–72 (AIP Conf. 1170, American Institute of Physics, 2009)

    Google Scholar 

  8. Udalski, A. et al. The Optical Gravitational Lensing Experiment. Cepheids in the Magellanic Clouds. IV. Catalog of Cepheids from the Large Magellanic Cloud. Acta Astron. 49, 223–317 (1999)

    ADS  Google Scholar 

  9. Alcock, C. et al. The MACHO Project Large Magellanic Cloud variable star inventory. XII. Three Cepheid variables in eclipsing binaries. Astrophys. J. 573, 338–350 (2002)

    Article  ADS  Google Scholar 

  10. Soszynski, I. et al. The Optical Gravitational Lensing Experiment. The OGLE-III catalog of variable stars. I. Classical Cepheids in the Large Magellanic Cloud. Acta Astron. 58, 163–185 (2008)

    ADS  Google Scholar 

  11. Wilson, R. E. & Devinney, E. J. Realization of accurate close-binary light curves: application to MR Cygni. Astrophys. J. 166, 605–620 (1971)

    Article  ADS  Google Scholar 

  12. Van Hamme, W. & Wilson, R. E. Third-body parameters from whole light and velocity curves. Astrophys. J. 661, 1129–1151 (2007)

    Article  ADS  Google Scholar 

  13. Gieren, W., Fouqué, P. & Gómez, M. Cepheid period-radius and period-luminosity relations and the distance to the Large Magellanic Cloud. Astrophys. J. 496, 17–30 (1998)

    Article  ADS  Google Scholar 

  14. Lepischak, D., Welch, D. L. & van Kooten, P. B. M. The nature of the companion to the eclipsing overtone Cepheid MACHO 81.8997.87. Astrophys. J. 611, 1100–1106 (2004)

    Article  ADS  Google Scholar 

  15. Soszynski, I. et al. The Optical Gravitational Lensing Experiment. The OGLE-III catalog of variable stars. II. Type II Cepheids and anomalous Cepheids in the Large Magellanic Cloud. Acta Astron. 58, 293–312 (2008)

    ADS  Google Scholar 

  16. Bono, G., Castellani, V. & Marconi, M. Classical Cepheid pulsation models. III. The predictable scenario. Astrophys. J. 529, 293–317 (2000)

    Article  ADS  Google Scholar 

  17. Luck, R. E., Moffett, T. J., Barnes, T. G. & Gieren, W. P. Magellanic Cloud Cepheids–abundances. Astron. J. 115, 605–634 (1998)

    Article  ADS  CAS  Google Scholar 

  18. Keller, S. C. Cepheid mass loss and the pulsation-evolutionary mass discrepancy. Astrophys. J. 677, 483–487 (2008)

    Article  ADS  Google Scholar 

  19. Neilson, H. R. & Lester, J. B. On the enhancement of mass loss in Cepheids due to radial pulsation. Astrophys. J. 684, 569–587 (2008)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Chilean Center for Astrophysics FONDAP, the BASAL Centro de Astrofisica y Tecnologias Afines (CATA), NSF, the Polish Ministry of Science, the Foundation for Polish Science (FOCUS, TEAM), and the GEMINI-CONICYT Fund. The OGLE project has received funding from the European Research Council (‘Advanced Grants’). We thank the staff astronomers at Las Campanas and ESO La Silla who provided support in the data acquisition. We also thank D. Queloz, S. Udry and C. Lovis for their help in reducing and analysing the radial-velocity data obtained with the HARPS instrument.

Author information

Authors and Affiliations

  1. Departamento de Astronomìa, Universidad de Concepción, Casilla 160-C, Concepciòn, Chile,

    G. Pietrzyński, W. Gieren, D. Graczyk & B. Pilecki

  2. Obserwatorium Astronomiczne Uniwersytetu Warszawskiego, Aleje Ujazdowskie 4, 00-478 Warszawa, Poland ,

    G. Pietrzyński, A. Udalski, I. Soszyński & B. Pilecki

  3. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, 911101-1292, California, USA

    I. B. Thompson

  4. Dipartimento di Fisica Universita’ di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Rome, Italy,

    G. Bono

  5. INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00040 Monte Porzio Catone, Italy ,

    G. Bono

  6. Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile,

    D. Minniti

Authors
  1. G. Pietrzyński
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. I. B. Thompson
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. W. Gieren
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. D. Graczyk
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. G. Bono
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. A. Udalski
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. I. Soszyński
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. D. Minniti
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. B. Pilecki
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

G.P., photometric and spectroscopic observations and reductions, data analysis; I.B.T., spectroscopic observations and reductions, radial-velocity measurements, data analysis; W.G., spectroscopic observations, data analysis; D.G., spectroscopic observations, modelling, data analysis; G.B., theoretical models; A.U., photometric observations and reductions, data analysis; I.S., photometric observations and reductions; D.M., spectroscopic observations; B.P., modelling. G.P. and W.G. worked jointly to draft the manuscript, with all authors reviewing and contributing to its final form.

Corresponding author

Correspondence to G. Pietrzyński.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Pietrzyński, G., Thompson, I., Gieren, W. et al. The dynamical mass of a classical Cepheid variable star in an eclipsing binary system. Nature 468, 542–544 (2010). https://doi.org/10.1038/nature09598

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature09598

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing