Article

# A search for star-planet interactions in chromospheric lines

12/2010; DOI:abs/1012.1720
Source: arXiv

ABSTRACT Massive planets in very close orbits around their central stars can induce so-called star-planet interactions (SPI), which may be of magnetic or gravitational nature. In both cases, SPI can potentially cause recurring chromospheric emission on the host star visible in Ca II H & K and/or H$\alpha$. The emission would be bound to the planetary orbit, not to the rotation period of the star. We searched for SPI in a sample of 7 stars with massive close-in planets using high-resolution spectroscopic data taken at HRS (HET) and FEROS (La Silla). We find no periodically recurring emission in the planet-hosting stars. In the case of HD 41004 AB, a binary system consisting of a K dwarf and an M dwarf, where the M dwarf is orbited by a brown dwarf companion, we find signs of cyclic variation in the Ca II K and H$\alpha$ emission lines that could be associated to interactions between the M dwarf and its companion. We present our first results of this interesting system that may become an important system for the understanding of SPI. Comment: 5 pages, 9 figures, proceeding of the Cool Stars 16 Conference (Seattle 2010)

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### Keywords

5 pages

7 stars

binary system

Ca II H & K

Ca II K

cases

central stars

chromospheric emission

Cool Stars 16 Conference

gravitational nature

H$\alpha$ emission lines

high-resolution spectroscopic data

host star visible

interesting system

La Silla

massive close-in planets

Massive planets

planet-hosting stars

planetary orbit

SPI