|Multiplicity of Late-type B Stars with HgMn Peculiarity
|462, Progress in Solar/Stellar Physics with Helio- and Asteroseismology
|Schöller, M.; Correia, S.; Hubrig, S.; Ageorges, N.
|According to theoretical predictions, late B-type stars exhibiting strong
overabundances of the chemical elements Hg and Mn in their atmospheres,
the so-called HgMn stars,
are expected to display slow pulsations similar to those in Slowly Pulsating B stars.
One of the major characteristics of this type of star is that they
are frequently found in binary and multiple systems.
We intend to study the multiplicity of HgMn stars,
looking for visual companions in the range of angular separation between
0.″05 and 8″.
We carried out a survey of 56 stars using diffraction-limited near-infrared
imaging with NAOS-CONICA at the Very Large Telescope (VLT).
Thirty-three companion candidates in 24 binaries, three triples, and one
quadruple system were detected.
Nine companion candidates were found for the first time in this study.
Five objects are likely to be chance projections. The detected companion candidates
have K magnitudes between 5.″95 and 18.″07 and angular separations ranging
from < 0.″05 to 7.″8, corresponding to linear projected separations of
Our study clearly confirms that HgMn stars are frequently members of binary and
Taking into account companions found by other techniques, the multiplicity
fraction in our sample may be as high as 91%.
The membership in binary and multiple systems seems to be a key to
understanding the abundance patterns in these stars.