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A dynamical calibration of the mass–luminosity relation at very low stellar masses and young ages

Nature volume 433, pages 286–289 (2005)Cite this article

Abstract

Mass is the most fundamental parameter of a star, yet it is also one of the most difficult to measure directly. In general, astronomers estimate stellar masses by determining the luminosity and using the ‘mass–luminosity’ relationship1,2, but this relationship has never been accurately calibrated for young, low-mass stars and brown dwarfs3. Masses for these low-mass objects are therefore constrained only by theoretical models1,2. A new high-contrast adaptive optics camera4,5,6 enabled the discovery of a young (50 million years) companion only 0.156 arcseconds (2.3 au) from the more luminous (> 120 times brighter) star AB Doradus A. Here we report a dynamical determination of the mass of the newly resolved low-mass companion AB Dor C, whose mass is 0.090 ± 0.005 solar masses. Given its measured 1–2-micrometre luminosity, we have found that the standard mass–luminosity relations1,2 overestimate the near-infrared luminosity of such objects by about a factor of ∼2.5 at young ages. The young, cool objects hitherto thought to be substellar in mass are therefore about twice as massive, which means that the frequency of brown dwarfs and planetary mass objects in young stellar clusters has been overestimated.

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Figure 1: Discovery image of AB Dor C with the NACO SDI high contrast camera.
Figure 2: The AB Dor A and C orbital solution.
Figure 3: The spectrum of AB Dor C.
Figure 4: The observations are poorly fitted by the models.

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References

  1. Chabrier, G., Baraffe, I., Allard, F. & Hauschildt, P. Evolutionary models for very low-mass stars and brown dwarfs with dusty atmospheres. Astrophys. J. 542, 464–472 (2000)

    Article  ADS  CAS  Google Scholar 

  2. Burrows, A., Hubbard, W. B., Lunine, J. I. & Liebert, J. The theory of brown dwarfs and extrasolar giant planets. Rev. Mod. Phys. 73, 719–765 (2001)

    Article  ADS  CAS  Google Scholar 

  3. Bouy, H. et al. First determination of the dynamical mass of a binary L dwarf. Astron. Astrophys. 423, 341–352 (2004)

    Article  ADS  CAS  Google Scholar 

  4. Close, L. M. et al. Extrasolar planetary science with adaptive optics. ESO workshop on adaptive optics. Astron. Soc. Pacif. (in the press)

  5. Lenzen, R., Close, L. M., Brandner, W., Biller, B. & Hartung, M. A novel simultaneous differential imager for the direct imaging of giant planets. SPIE Symp. 5492,(in the press)

  6. Biller, B. et al. An algorithm for the suppression of speckle-noise with the VLT & MMT SDI cameras. SPIE Symp. 5490,(in the press)

  7. Perryman, M. A. C. et al. The HIPPARCOS catalogue. Astron. Astrophys. 323, L49–L52 (1997)

    ADS  Google Scholar 

  8. Zuckerman, B., Song, I. & Bessell, M. S. The AB Doradus moving group. Astrophys. J. 613, L65–L68 (2004)

    Article  ADS  CAS  Google Scholar 

  9. Innis, J. L., Coates, D. W., Thompson, K. & Robinson, R. D. A study of the rapidly rotating variable star HD 36705 (AB Doradus). Astron. Soc. Aust. 6, 156–160 (1985)

    Article  ADS  CAS  Google Scholar 

  10. Mewe, R., Kaastra, J. S., White, S. M. & Pallavicini, R. Simultaneous EUVE & ASCA observations of AB Doradus: temperature structure and abundances of the quiescent corona. Astron. Astrophys. 315, 170–178 (1996)

    ADS  Google Scholar 

  11. Vilhu, O., Gustafsson, B. & Walter, F. M. Spectroscopy of southern active stars. II. HD 32918, HD 82558, BD - 22 deg 3467, AB Doradus (HD 36705) and RST 137 B. Astron. Astrophys. 241, 167–175 (1991)

    ADS  CAS  Google Scholar 

  12. Randich, S., Pallavicini, R., Meola, G., Stauffer, J. R. & Balachandran, S. C. Membership, lithium, and metallicity in the young open clusters IC 2602 and IC 2391: Enlarging the sample. Astron. Astrophys. 372, 862–878 (2001)

    Article  ADS  CAS  Google Scholar 

  13. Stelzer, B. & Neuhäuser, R. X-ray emission from young stars in the Tucanae association. Astron. Astrophys. 361, 581–593 (2000)

    ADS  Google Scholar 

  14. Barrado y Navascués, D., Deliyannis, C. P. & Stauffer, J. R. WIYN open cluster study. V. Lithium depletion and metallicity in G and K dwarfs of the open cluster M35. Astrophys. J. 549, 452–466 (2001)

    Article  ADS  Google Scholar 

  15. Stauffer, J. R. et al. Why are the K dwarfs in the Pleiades so blue? Astron. J. 126, 833–847 (2003)

    Article  ADS  CAS  Google Scholar 

  16. Martin, E. L. & Brandner, W. On the evolutionary status of two very active visual binaries. Astron. Astrophys. 294, 744–746 (1995)

    ADS  Google Scholar 

  17. Guirado, J. C. et al. Astrometric detection of a low-mass companion orbiting the star AB Doradus. Astrophys. J. 490, 835–846 (1997)

    Article  ADS  Google Scholar 

  18. D'Antona, F. & Mazzitelli, I. Stellar models and luminosity functions for the Population II Main Sequence down to its lower end. Astrophys. J. 456, 329–349 (1996)

    Article  ADS  Google Scholar 

  19. Hillenbrand, L. A. & White, R. J. An assessment of dynamical mass constraints on Pre-Main-Sequence evolutionary tracks. Astrophys. J. 604, 741–757 (2004)

    Article  ADS  CAS  Google Scholar 

  20. Close, L. M., Siegler, N., Freed, M. & Biller, B. Detection of nine M8.0–L0.5 binaries: the very low mass binary population and its implications for brown dwarf and very low mass star formation. Astrophys. J. 587, 407–422 (2003)

    Article  ADS  Google Scholar 

  21. Luhman, K. L. Young low-mass stars and brown dwarfs in IC 348. Astrophys. J. 525, 466–481 (1999)

    Article  ADS  CAS  Google Scholar 

  22. Martín, E. L. et al. Membership and multiplicity among very low mass stars and brown dwarfs in the Pleiades cluster. Astrophys. J. 543, 299–312 (2000)

    Article  ADS  Google Scholar 

  23. Ségransan, D. et al. Mass-luminosity relations of very low mass stars. Proc. IAU Symp. 211, 413–420 (2003)

    ADS  Google Scholar 

  24. Lucas, P. W. & Roche, P. F. A population of very young brown dwarfs and free-floating planets in Orion. Mon. Not. R. Astron. Soc. 314, 858–864 (2000)

    Article  ADS  Google Scholar 

  25. Zapatero Osorio, M. R. et al. The substellar population in σ Orionis. Proc. IAU Symp. 211, 111–115 (2003)

    ADS  Google Scholar 

  26. Burgasser, A. J. et al. S Orionis 70: just a foreground field brown dwarf? Astrophys. J. 604, 827–831 (2004)

    Article  ADS  CAS  Google Scholar 

  27. Marois, C. et al. TRIDENT: an infrared camera optimized for the detection of methanated substellar companions of nearby stars. High-contrast imaging for exo-planet detection. (ed. Schultz, A. B.) Proc. SPIE 4860, 130–137 (2003).

  28. Lenzen, R. et al. NAOS-CONICA first on sky results in a variety of observing modes. Instrument design and performance for optical/infrared ground-based telescopes. (eds Iye, M. & Moorwood, A. F. M.) Proc. SPIE 4841, 944–952 (2003).

  29. Wilking, B. A., Green, T. P. & Meyer, M. R. Spectroscopy of brown dwarf candidates in the ρ Oph molecular core. Astron. J. 117, 469–482 (1999)

    Article  ADS  CAS  Google Scholar 

  30. Maiolino, R., Rieke, G. H. & Rieke, M. J. Correction of the atmospheric transmission in infrared spectroscopy. Astron. J. 111, 537–545 (1996)

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

We thank A. Kaufer, M. Kasper, J. Spyromilio, P. Gandhi and R. Gilmozzi for assistance with SDI commissioning. We thank O. Marco for support during the spectral observations. We thank D. McCarthy and M. Rademacher for help with the initial design of the NACO SDI optics. L.M.C. and B.B. acknowledge support from a NASA Origins grant. J.C.G. acknowledges support from a Spanish DGICYT grant. E.E.M. is supported by a Clay Fellowship from the Smithsonian Astrophysical Observatory. L.M.C. acknowledges support from an NSF Career award and SEC and EMC.

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Authors and Affiliations

  1. Steward Observatory, University of Arizona, Tucson, Arizona, 85721, USA

    Laird M. Close, Eric L. Nielsen, Eric E. Mamajek & Beth Biller

  2. Max-Plank-Institut fur Astronomie, Konigstuhl 17, D-69117, Heidelberg, Germany

    Rainer Lenzen & Wolfgang Brandner

  3. Departament d'Astronomia i Astrofisica, Universitat de Valencia, E-46100, Burjassot, Valencia, Spain

    Jose C. Guirado

  4. European Southern Observatory, Alonso de Cordova 3107, 19, Santiago, Chile

    Markus Hartung & Chris Lidman

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  1. Laird M. Close
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Correspondence to Laird M. Close.

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Close, L., Lenzen, R., Guirado, J. et al. A dynamical calibration of the mass–luminosity relation at very low stellar masses and young ages. Nature 433, 286–289 (2005). https://doi.org/10.1038/nature03225

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