PG 1115+166 – a long-period DA+DB binary

PG 1115 + 166 – a long period DA + DB binary .

We present spectra of the DAB white dwarf PG1115+166. Radial velocity measurements of the Balmer lines and the HeI 6678Å line show that this is a binary white dwarf with a period of 30.09d in which the Balmer lines move in anti-phase to the HeI line, i.e., PG1115+166 is a DA+DB binary. The minimum masses of the stars are MDA = 0.43±0.15M⊙ and MDB = 0.52±0.12M⊙. The separation of the stars is ab...

The first PG 1159 close binary system

The archival spectrum of SDSS J212531.92-010745.9 shows not only the typical signature of a PG 1159 star, but also indicates the presence of a companion. With time-series photometry of SDSS J212531.92-010745.9 during 10 nights, spread over one month, with the Tübingen 80 cm and the Göttingen 50 cm telescopes, the binary nature of this object has recently been proven. An orbital period of 6.9 h ...

A Long Gestation Period

A novel binary chlorhexidine-chitosan irrigant with high permeability, and long lasting synergic antibacterial effect.

Objective.Chlorhexidine gluconate (CHX) is an irrigant with a  reasonable antibacterial ability and rather high permeability yet often fails to remove the smear layer. To solve this problem, CHX is upgraded through its complexion with chitosan (CS). Methods.Molar roots are split longitudinally by a rotary diamond saw. Chlorhexidine-chitosan (CHX-CS) is made by combinatio...

Timing models for the long - orbital period binary pulsar PSR B 1259 − 63

The pulsar PSR B1259−63 is in a highly eccentric 3.4-yr orbit with the Be star SS 2883. Timing observations of this pulsar, made over a 7-yr period using the Parkes 64-m radio telescope, cover two periastron passages, in 1990 August and 1994 January. The timing data cannot be fitted by the normal pulsar and Keplerian binary parameters. A timing solution including a (non-precessing) Keplerian or...