On the reflection effect in three sdOB binary stars

Hilditch, R. W.; Harries, Tim J.; Hill, Graham

doi:10.1093/mnras/279.4.1380

Cited by 66 publications

(88 citation statements)

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“…4 of Rauch & Werner (2003) is incorrect. In its top panel, the data of Hilditch et al (1996) is erroneously shown with an offset of +0.5 d, and the v rad values in the bottom panel have an incorrect sign. This explains the period deviation that was previously found (Sect.…”

Section: Orbital Periodmentioning

confidence: 99%

Search with UVES and X-Shooter for signatures of the low-mass secondary in the post common-envelope binary AA Doradus

Hoyer

Rauch

Werner

et al. 2015

A&A

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Context. AA Dor is a close, totally eclipsing, post common-envelope binary with an sdOB-type primary star and an extremely lowmass secondary star, located close to the mass limit of stable central hydrogen burning. Within error limits, it may either be a brown dwarf or a late M-type dwarf. Aims. We aim to extract the secondary's contribution to the phase-dependent composite spectra. The spectrum and identified lines of the secondary decide on its nature. Methods. In January 2014, we measured the phase-dependent spectrum of AA Dor with X-Shooter over one complete orbital period. Since the secondary's rotation is presumable synchronized with the orbital period, its surface strictly divides into a day and night side. Therefore, we may obtain the spectrum of its cool side during its transit and of its hot, irradiated side close to its occultation. We developed the Virtual Observatory (VO) tool TLISA to search for weak lines of a faint companion in a binary system. We successfully applied it to the observations of AA Dor. Results. We identified 53 spectral lines of the secondary in the ultraviolet-blue, visual, and near-infrared X-Shooter spectra that are strongest close to its occultation. We identified 57 (20 additional) lines in available Ultraviolet and Visual Echelle Spectrograph (UVES) spectra from 2001. The lines are mostly from C ii-iii and O ii, typical for a low-mass star that is irradiated and heated by the primary. We verified the orbital period of P = 22 597.033201 ± 0.00007 s and determined the orbital velocity K sec = 232.9 +16.6 −6.5 km s −1 of the secondary. The mass of the secondary is M sec = 0.081 +0.018 −0.010 M and, hence, it is not possible to reliably determine a brown dwarf or an M-type dwarf nature. Conclusions. Although we identified many emission lines of the secondary's irradiated surface, the resolution and signal-to-noise ratio of our UVES and X-Shooter spectra are not good enough to extract a good spectrum of the secondary's nonirradiated hemisphere.

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Section: Orbital Periodmentioning

confidence: 99%

Search with UVES and X-Shooter for signatures of the low-mass secondary in the post common-envelope binary AA Doradus

Hoyer

Rauch

Werner

et al. 2015

A&A

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“…1) are largely dominated by reflection effects, and resembles its optical light curves (Hilditch et al 1996). The amplitude of the reflection effect at NIR is ΔH ∼ 0.7 mag against 0.55 mag in the V band.…”

Section: Kv Velmentioning

confidence: 80%

“…As stated by Landolt & Drilling (1986) and later by Hilditch et al (1996), modeling of infrared light curves of this binary would be key to our understanding of its properties and of others of its kind, setting our motivation for this analysis.…”

Section: Kv Velmentioning

confidence: 99%

“…Beyond this wavelength the secondary star contribution likely becomes significant and its distorted shape could account for the missfitting. In that sense, Hilditch et al (1996) analyzed the same data of Landolt & Drilling (1986) with an improved model that accounted for the secondary flux and distorted shape as well as for illumination and atmospheric (e.g., limb-and gravitydarkening) effects. Although this improved model was able to provide good fit to the data, a problem with the modeling illumination procedure was later reported by Hilditch et al (2003).…”

Section: Kv Velmentioning

confidence: 99%

“…We used the previous determination of secondary star properties (Hilditch et al 1996) to select square-root limb-darkening Landolt & Drilling (1986). References.…”

Section: Kv Velmentioning

confidence: 99%

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Near-infrared SOAR photometric observations of post common envelope binaries

Ribeiro

Baptista

2011

A&A

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Context. From a number of known post common envelopes binaries (PCEB) only a handful have yet been observed at near-infrared (NIR) wavelengths, and even fewer have modeled NIR light curves. At shorter wavelengths one has access to the cooler and larger components of these systems and has a chance to detect emission from its faint and heavily irradiated atmospheres. Aims. By modeling NIR light curves of PCEBs, we intend to constrain their system parameters and study the properties of the system components. Methods. Here we present simultaneous NIR JHK s light curves of two PCEBs obtained with the 4 m SOAR telescope. Results. KV Vel and TW Crv are long-period (P orb = 8.6 h and 7.9 h, respectively) PCEBs with strong irradiation effects. The results of light-curve fitting provided solutions with inclination i = (47 ± 5) • , mass ratio q = 0.3 ± 0.1, and radius of the secondary R 2 /a = 0.24 +0.05 −0.03 (where a is the orbital separation) for KV Vel, and i = (42 ± 9) • , q = 0.28 ± 0.04, and R 2 /a = 0.22 ± 0.01 for TW Crv, respectively. For KV Vel, we obtain an average value for the albedo of the secondary star of α = 0.43, consistent in the J, H and K s band. For TW Crv, on the other hand, we obtain values of α J = (0.4 ± 0.1) for the J and α H = (0.3 ± 0.1) for H-band.

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On the reflection effect in three sdOB binary stars

Cited by 66 publications

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Search with UVES and X-Shooter for signatures of the low-mass secondary in the post common-envelope binary AA Doradus

Search with UVES and X-Shooter for signatures of the low-mass secondary in the post common-envelope binary AA Doradus

Near-infrared SOAR photometric observations of post common envelope binaries

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