MagAO imaging of long-period objects (MILO). II. A puzzling white dwarf around the sun-like star HD 11112

Timothy J. Rodigas, P. Bergeron, Amélie Simon, Pamela Arriagada, Jacqueline K. Faherty, Guillem Anglada-Escudé, Eric E. Mamajek, Alycia Weinberger, R. Paul Butler, Jared R. Males, Katie Morzinski, Laird M Close, Philip M Hinz, Jeremy Bailey, Brad Carter, James S. Jenkins, Hugh Jones, Simon O'Toole, C. G. Tinney, Rob WittenmyerJohn Debes

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2 Scopus citations

Abstract

HD 11112 is an old, Sun-like star that has a long-term radial velocity (RV) trend indicative of a massive companion on a wide orbit. Here we present direct images of the source responsible for the trend using the Magellan Adaptive Optics system. We detect the object (HD 11112B) at a separation of 2.″2 (100 au) at multiple wavelengths spanning 0.6-4 μm and show that it is most likely a gravitationally bound cool white dwarf. Modeling its spectral energy distribution suggests that its mass is 0.9-1.1 M o, which corresponds to very high eccentricity, near edge-on orbits from a Markov chain Monte Carlo analysis of the RV and imaging data together. The total age of the white dwarf is >2σ, which is discrepant with that of the primary star under most assumptions. The problem can be resolved if the white dwarf progenitor was initially a double white dwarf binary that then merged into the observed high-mass white dwarf. HD 11112B is a unique and intriguing benchmark object that can be used to calibrate atmospheric and evolutionary models of cool white dwarfs and should thus continue to be monitored by RV and direct imaging over the coming years.

Original languageEnglish (US)
Article number177
JournalAstrophysical Journal
Volume831
Issue number2
DOIs
StatePublished - Nov 10 2016

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Keywords

  • instrumentation: adaptive optics
  • stars: individual (HD 11112)
  • techniques: high angular resolution
  • techniques: radial velocities
  • white dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Rodigas, T. J., Bergeron, P., Simon, A., Arriagada, P., Faherty, J. K., Anglada-Escudé, G., Mamajek, E. E., Weinberger, A., Butler, R. P., Males, J. R., Morzinski, K., Close, L. M., Hinz, P. M., Bailey, J., Carter, B., Jenkins, J. S., Jones, H., O'Toole, S., Tinney, C. G., ... Debes, J. (2016). MagAO imaging of long-period objects (MILO). II. A puzzling white dwarf around the sun-like star HD 11112. Astrophysical Journal, 831(2), [177]. https://doi.org/10.3847/0004-637X/831/2/177