Skip to main content

Thank you for visiting 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 binary progenitor of Tycho Brahe's 1572 supernova


The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion1,2,3. Unless the companion star is another white dwarf (in which case it should be destroyed by the mass-transfer process itself), it should survive and show distinguishing properties. Tycho's supernova4,5 is one of only two type Ia supernovae observed in our Galaxy, and so provides an opportunity to address observationally the identification of the surviving companion. Here we report a survey of the central region of its remnant, around the position of the explosion, which excludes red giants as the mass donor of the exploding white dwarf. We found a type G0–G2 star, similar to our Sun in surface temperature and luminosity (but lower surface gravity), moving at more than three times the mean velocity of the stars at that distance, which appears to be the surviving companion of the supernova.

This is a preview of subscription content

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Positions and proper motions of stars.
Figure 2: The SN 1572 field and radial velocity of the stars.
Figure 3: Model fits to observed spectra.


  1. 1

    Branch, D., Livio, M., Yungelson, L. R., Boffi, F. & Baron, E. In search of the progenitors of Type Ia Supernovae. Publ. Astron. Soc. Pacif. 107, 1019–1029 (1995)

    ADS  Article  Google Scholar 

  2. 2

    Ruiz-Lapuente, P., Canal, R. & Burkert, A. in Thermonuclear Supernovae (eds Ruiz-Lapuente, P., Canal, R. & Isern, J.) 205–230 (Kluwer Academic, Dordrecht, 1997)

    Google Scholar 

  3. 3

    Livio, M. in Type Ia Supernovae: Theory and Cosmology (eds Niemeyer, J. C. & Truran, J. W.) 33–48 (Cambridge Univ. Press, Cambridge, 2000)

    Google Scholar 

  4. 4

    Brahe, T. Astronomiae Instauratae Progymnasmata. In Opera Omnia Vol. 2 (ed. Dreyer, I. L. E.) 307 (Swets & Zeitlinger, Amsterdam, 1972) (1603)

    Google Scholar 

  5. 5

    Baade, W. B Cassiopeiae as a supernova of Type I. Astrophys. J. 102, 309–317 (1945)

    ADS  Article  Google Scholar 

  6. 6

    Baldwin, J. E. & Edge, D. O. Radio emission from the remnants of the supernovae of 1572 and 1604. Observatory 77, 139–143 (1957)

    ADS  Google Scholar 

  7. 7

    Hughes, J. P. et al. ASCA observations of the Large Magellanic Cloud supernova remnant sample: Typing supernovae from their remnants. Astrophys. J. 444, L81–L84 (1995)

    ADS  CAS  Article  Google Scholar 

  8. 8

    Canal, R., Méndez, J. & Ruiz-Lapuente, P. Identification of the companion stars of Type Ia supernovae. Astrophys. J. 550, L53–L56 (2001)

    ADS  Article  Google Scholar 

  9. 9

    Ruiz-Lapuente, P. Tycho Brahe's supernova: light from centuries past. Astrophys. J. 612, 357–363 (2004)

    ADS  CAS  Article  Google Scholar 

  10. 10

    Ruiz-Lapuente, P. et al. in From Twilight to Highlight: the Physics of Supernovae (eds Hillebrandt, W. & Leibundgut, B.) 140–147 (Springer, Berlin, 2003)

    Book  Google Scholar 

  11. 11

    Hachisu, I., Kato, M. & Nomoto, K. A new model for progenitor systems of Type Ia supernovae. Astrophys. J. 470, L97–L100 (1996)

    ADS  Article  Google Scholar 

  12. 12

    Li, X.-D. & van den Heuvel, E. P. J. Evolution of white dwarf binaries: supersoft X-ray sources and progenitors of type Ia supernovae. Astron. Astrophys. 322, L9–L12 (1997)

    ADS  Google Scholar 

  13. 13

    Livio, M. & Truran, J. W. Type I supernovae and accretion-induced collapses from cataclysmic variables? Astrophys. J. 389, 695–703 (1992)

    ADS  CAS  Article  Google Scholar 

  14. 14

    Marietta, E., Burrows, A. & Fryxell, B. Type Ia supernova explosions in binary systems: the impact on the secondary star and its consequences. Astrophys. J. Suppl. 128, 615–650 (2000)

    ADS  CAS  Article  Google Scholar 

  15. 15

    Podsiadlowski, P. On the evolution and appearance of a surviving companion after a Type Ia supernova explosion. Preprint at 〈〉 (2003).

  16. 16

    Lejeune, Th., Cuisinier, F. & Buser, R. A standard stellar library for evolutionary synthesis. Astron. Astrophys. Suppl. Ser. 125, 229–246 (1997)

    ADS  Article  Google Scholar 

  17. 17

    Brand, J. & Blitz, L. The velocity field of the outer Galaxy. Astron. Astrophys. 275, 67–90 (1993)

    ADS  Google Scholar 

  18. 18

    Binney, J. & Merrifield, M. Galactic Astronomy (Princeton Univ. Press, Princeton, 1998)

    Google Scholar 

  19. 19

    Dehnen, W. & Binney, J. Local stellar kinematics from Hipparcos data. Mon. Not. R. Astron. Soc. 298, 387–394 (1998)

    ADS  Article  Google Scholar 

  20. 20

    Ruiz-Lapuente, P. Probing the nature of Type Ia SNa through HST astrometry. 〈〉 (2003).

  21. 21

    Ruiz-Lapuente, P. in Proc. Conf. Astronomy as a Model for the Sciences in Early Modern Times, Munich, 21–23 March 2003 (eds Fritscher, B. & Kühne, A.) (Erwin Rauner, Augsberg, in the press)

  22. 22

    Hughes, J. P. The expansion of the X-ray remnant of Tycho's supernova (SN 1572). Astrophys. J. 545, L53–L56 (2000)

    ADS  Article  Google Scholar 

  23. 23

    Decourchelle, A. et al. XMM-Newton observation of the Tycho supernova remnant. Astron. Astrophys. 365, L218–L224 (2001)

    ADS  CAS  Article  Google Scholar 

  24. 24

  25. 25

    Anders, E. & Grevesse, N. Abundances of the elements—meteoritic and solar. Geochim. Cosmochim. Acta 53, 197–214 (1989)

    ADS  CAS  Article  Google Scholar 

  26. 26

    Kurucz, R. L. ATLAS9 Stellar Atmospheres Programs, Grids of Model Atmospheres and Line Data [CD-ROM]. (Smithsonian Astrophysical Observatory, Cambridge, MA, 1993)

  27. 27

    Gustaffson, B., Bell, R. A., Eriksson, K. & Nordlund, Å. A grid of model atmospheres for metal-deficient giant stars. Astron. Astrophys. 42, 407–432 (1975)

    ADS  Google Scholar 

  28. 28

    Schmidt-Kaler, Th. in Landolt-Börnstein, New Ser. VI, Vol. 2b (ed. Hellwege, K.-H.) 1–34 (Springer, Berlin, 1982)

    Google Scholar 

Download references


P.R.L. thanks C. Ruiz Ogara for giving her the spirit to complete this survey. We thank the support staff at the European Northern Observatory at La Palma for their assistance throughout this project, as well as the support staff at the W. M. Keck Observatory and NASA/ESA Hubble Space Telescope. We express our special gratitude to C. Abia, F. Figueras, C. Guirao, R. Mignani and J. Torra for diverse consultations. This work has been supported by DURSI, DGYCIT (to P.R.L., J.M. and R.C.), PPARC (to J.M. and S.J.S.) and by NSF (to A.V.F., R.C., R.J.F. and R.L.K.).

Author information



Corresponding author

Correspondence to Pilar Ruiz-Lapuente.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Table 1

Spectroscopic runs at the 4.2m William Herschel Telescope (WHT), the 2.5m Nordic Optical Telescope (NOT) and the 10m Keck I and Keck II telescopes used in this work. (PDF 83 kb)

Supplementary Table 2

Hubble Space Telescope data sets used for proper motion measurements. (PDF 159 kb)

Supplementary Table 3

Magnitudes and radial velocities of the stars. (PDF 111 kb)

Supplementary Methods

Specification of the the WFPC2 measurements. (PDF 100 kb)

Supplementary Note 1

Note on the origin of the asymmetry in Tycho SNR. (PDF 83 kb)

Supplementary Discussion

Further discussion on red giant and main sequence stars. (PDF 217 kb)

Supplementary Figure 1

Spectra of Tycho G showing it to be a subgiant not belonging to the halo population. (PDF 278 kb)

Supplementary Note 2

Tycho Brahe SN as a U Sco system. (PDF 77 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ruiz-Lapuente, P., Comeron, F., Méndez, J. et al. The binary progenitor of Tycho Brahe's 1572 supernova. Nature 431, 1069–1072 (2004).

Download citation

Further reading


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.


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