Spectroscopy of the Inner Companion of the Pulsar PSR J0337+1715
Abstract
The hierarchical triple system PSR J0337+1715 offers an unprecedented laboratory to study secular evolution of interacting systems and to explore the complicated mass-transfer history that forms millisecond pulsars and helium-core white dwarfs. The latter in particular, however, requires knowledge of the properties of the individual components of the system. Here we present precise optical spectroscopy of the inner companion in the PSR J0337+1715 system. We confirm it as a hot, low-gravity DA white dwarf with T eff = 15, 800 ± 100 K and log10(g) = 5.82 ± 0.05. We also measure an inner mass ratio of 0.1364 ± 0.0015, entirely consistent with that inferred from pulsar timing, and a systemic radial velocity of 29.7 ± 0.3 km s-1. Combined with the mass (0.19751 M ⊙) determined from pulsar timing, our measurement of the surface gravity implies a radius of 0.091 ± 0.005 R ⊙ combined further with the effective temperature and extinction, the photometry implies a distance of 1300 ± 80 pc. The high temperature of the companion is somewhat puzzling: with current models, it likely requires a recent period of unstable hydrogen burning, and suggests a surprisingly short lifetime for objects at this phase in their evolution. We discuss the implications of these measurements in the context of understanding the PSR J0337+1715 system, as well as of low-mass white dwarfs in general.
Based on observations obtained under Program GN-2012B-Q-43 at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2014
- DOI:
- 10.1088/2041-8205/783/1/L23
- arXiv:
- arXiv:1402.0407
- Bibcode:
- 2014ApJ...783L..23K
- Keywords:
-
- binaries: spectroscopic;
- pulsars: individual: PSR J0337+1715;
- stars: atmospheres;
- stars: neutron;
- white dwarfs;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- ApJ Letters, in press. 6 pages, two figures. v2 fixes typo