Hierarchical Triples

The stability of hierarchical triple stars is largely determined by the pericenter distance of the outer orbit. There are many studies of this in the literature e.g. by Harrington 7 , Bailyn 3 , Kiseleva and Eggleton 6 , Mardling and Aarseth 1, 21 . Those authors give various estimates for the ratio of the pericentre distance Rperi of the outer orbit to the semi-major axis ain of the inner orbit Here Q2 max(m1 m2,m2 m1) 3, Q3 (miw+3m2) 3 in the Eggleton-Kiseleva criterion. The masses mi, m2 are...

Population of Kozai Triples

About 60 of all triples have inner binaries with both components on the Main Sequence (MS-MS binaries), and 30 of them are Kozai triples. A typical total mass of such binary is 1.3 0.2 Mq (see also Fig. 2). If Kozai mechanism leads to a merger, we find that these triples can provide 10 of all blue stragglers ever created. About 40 of all triples have inner binaries with a compact object (WD for white dwarf and NS for neutron star) and 35 (40 for WD-WD inner binaries) of them are Kozai triples....

Kozai Resonance

If the mutual inclination in a triple system is high enough, the system undergoes strong periodic variations in the inner eccentricity and the mutual inclination, known as the Kozai resonance 17,18 . Especially if the orbits are perpendicular, the inner eccentricity should reach the value e 1 This may thus restrict the existing triples to those having small mutual orbital inclinations (or near 180 degrees). On the other hand, the Kozai resonance is sensitively affected by other effects, such as...

The lighttime effect LITE

Sinusoidal modulation of times of eclipses in binaries may result from the binary revolution on a wide orbit around a center of mass with a companion, the LITE or the LIght-Time Effect 1 . Because intrinsic period changes in close binaries are quite common due to their strong physical interaction, the presence of the LITE is usually not conclusive, but can prompt other observations. 129 systems having more than 15 CCD or pe minima in the Cracow database (the May 2004 version, 8 ) were selected...

Discussion

The results of our study clearly confirm that HgMn stars are frequently found in multiple systems. It is especially intriguing that out of the 40 HgMn stars in the sample studied only two stars, HD 65950 and HD 70235, are not known to belong to a binary or multiple system. However, companionship can not be Fig. 1. NACO images of the wide systems in our sample. Upper row from left to right HD 32964, HD 34880, HD 36881 and HD 53929. Lower row from left to right HD 120709, HD 129174, HD 165493 and...

Abundance Analysis

Differential abundance analysis was performed as described in 2 , reaching errors of about 0.02 dex in the iron content difference. We fully exploit the physical link between the components (same distance from the Sun), deriving effective temperatures difference from ionization equilibrium and gravity difference from the magnitude difference. The analysis of 23 pairs, about half of the sample, shows that most of the pairs have abundance differences smaller than 0.02 dex and there are no pairs...

Is the BD Desert a Scalable Phenomenon

If BDs form in the same way as stars, we should observe an equivalent companion mass distribution for both. Then, the BD desert observed for solar-like stars could exist as a scaled-down equivalent also around BD primaries, this would be a giant planet desert, as illustrated in Fig. 3 (Joergens 2005 10 ). The here presented RV survey started to test its existence for BDs in Chal. For higher than solar-mass primaries, there are indeed hints that the BD desert might be a scalable phenomenon while...

Turning SB1s into SB2s Using Multi Order TODCOR

As just mentioned, identifying the cause of the observed residual-velocity variation is usually not easy. In particular, differentiating between a light body (a planet) orbiting the primary star and a heavier body (a low-mass star or a brown dwarf) orbiting the secondary component may be very tricky using one-dimensional cross-correlation techniques. One way to solve the problem is to use two-dimensional cross-correlation techniques. TODCOR (TwO-Dimensional CORrelation) is such an algorithm...

References

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