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

Rodigas, Timothy J. and Bergeron, P. and Simon, Amelie and Arriagada, Pamela and Faherty, Jacqueline K. and Anglada-Escude, Guillem and Mamajak, Eric E. and Weinberger, Alycia and Butler, R. Paul and Males, Jared R. and Morzinski, Katie and Close, Laird M. and Hinz, Philip M. and Bailey, Jeremy and Carter, Brad and Jenkins, James S. and Jones, Hugh and O'Toole, Simon and Tinney, C. G. and Wittenmyer, Rob and Debes, John (2016) MagAO imaging of long-period objects (MILO). II. A puzzling white dwarf around the sun-like star HD 11112. The Astrophysical Journal, 831 (2). ISSN 0004-637X

Text (Published Reportable Version)

Download (2543Kb) | Preview


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 ⊙, 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.

Statistics for USQ ePrint 30606
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Access to Published version allowed due to publisher copyright policy.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 27 Mar 2017 05:21
Last Modified: 11 Aug 2017 05:09
Uncontrolled Keywords: adaptive optics; high angular resolution; radial velocity; stars; HD 11112; binaries; white dwarfs
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.3847/0004-637X/831/2/177

Actions (login required)

View Item Archive Repository Staff Only