1997/10/29 by S. Mereghetti, G. L. Israel, L. Stella · 2 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Gamma-ray bursts and supernovae #Physics #Pulsar #Pulsars and Gravitational Waves Research #Roche lobe #Stars #White dwarf #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.1998.01396.x
5 pages (including figures). Using mn.sty and psfig.tex (included). Accepted for publication in MNRAS
arxiv created 1997/10/29 · openalex publication_date 1998/05/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report on two Rossi X-ray Timing Explorer (RXTE) observations of the anomalous X-ray pulsars 1E 1048.1-5937 and 1E 2259+586. Both sources have continued their almost constant spin-down during 1995/96. We carried out a search for orbital Doppler shifts, in their observed spin frequencies, deriving stringent limits on the projected semi-axis. Unless these systems have unlikely small inclinations, main-sequence companions can be excluded. If 1E 1048.1-5937 and 1E 2259+586 are indeed binary systems, their companion stars must be either white dwarfs, or helium-burning stars with M≲ 0.8 M☉, possibly underfilling their Roche lobe.