Evidence of a non-conservative mass transfer in the ultra-compact X-ray source XB 1916-053

Abstract

The dipping source XB 1916-053 is a compact binary system with an orbital period of 50 min harboring a neutron star. Using ten new {\it Chandra} observations and one {\it Swift/XRT} observation, we are able to extend the baseline of the orbital ephemeris; this allows us to exclude some models that explain the dip arrival times. The Chandra observations provide a good plasma diagnostic of the ionized absorber and allow us to determine whether it is placed at the outer rim of the accretion disk or closer to the compact object. From the available observations we are able to obtain three new dip arrival times extending the baseline of the orbital ephemeris from 37 to 40 years. From the analysis of the dip arrival times we confirm an orbital period derivative of $\dot{P}=1.46(3)\times 10^{-11}$ s s${}^{-1}$. We show that the $\dot{P}$ value and the luminosity values are compatible with a mass accretion rate lower than 10\% of the mass transfer rate. We show that the mass ratio $q=m_2/m_1$ of 0.048 explains the apsidal precession period and the nodal precession period. The observed absorption lines are associated with the presence of \ion{Ne}{x}, \ion{Mg}{xii}, \ion{Si}{xiv}, \ion{S}{xvi,} and \ion{Fe}{xxvi} ions. We observe a redshift in the absorption lines between $1.1\times 10^{-3}$ and $1.3\times 10^{-3}$. By interpreting it as gravitational redshift, as recently discussed in the literature, we find that the ionized absorber is placed at a distance of $10^8$ cm from the neutron star with a mass of 1.4 M${}_{\odot }$ and has a hydrogen atom density greater than $10^{15}$ cm${}^{-3}$. (Abstract abridged)

17 pages, 10 figures, accepted by Astronomy & Astrophysics

References in corpus (14)

• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium
• The variable X-ray spectrum of Markarian 766 - I. Principal components analysis
• Stability of helium accretion discs in ultracompact binaries
• Optical spectroscopy of (candidate) ultra-compact X-ray binaries: constraints on the composition of the donor stars
• The dynamics of eccentric accretion discs in superhump systems
• On the Fe K absorption - accretion state connection in the Galactic center neutron star X-ray binary AX J1745.6-2901
• Superhumps: Confronting Theory with Observation
• Parameterization studies of the properties of the X-ray dips for Low Mass X-ray binary X1916-053
• Chandra Observation of the Big Dipper X 1624-490
• Chandra Observation of the Dipping Source XB 1254-690
• Detection of Highly Ionized Metal Absorption Lines in the Ultracompact X-ray Dipper 4U 1916-05
• A Redshifted Inner Disk Atmosphere and Transient Absorbers in the Ultra-Compact Neutron Star X-ray Binary 4U 1916-053
• Spectral analysis of the dipping LMXB system XB 1916-053

Cited by in corpus (5)

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• Updated Orbital Ephemeris and Detection of Superhump Modulation in X-ray Band for the Ultra-Compact Low Mass X-ray Binary 4U 1820-30