Radial velocities for contact binaries - II. TZ Boo, XY Boo, TX Cnc, RZ Com, CC Com and Y Sex

Hipparcos parallaxes for η Boo and κ2 Boo: two successes for asteroseismology

The release of the Hipparcos catalogue (Perryman et al. 1997) provides an opportunity to check results from asteroseismology. This has already been done for the double-mode δ Scuti star SX Phe: Høg & Petersen (1997) found excellent agreement with the parallax derived from model calculations by Petersen & Christensen-Dalsgaard (1996). Here we show that Hipparcos parallaxes for two other stars ar...

Planetpol polarimetry of the exoplanet systems 55 Cnc and τ Boo ⋆

We present very sensitive polarimetry of 55 Cnc and τ Boo in an attempt to detect the partially polarised reflected light from the planets orbiting these two stars. 55 Cnc is orbited by a hot Neptune planet (55 Cnc e) at 0.038 AU, a hot Jupiter planet (55 Cnc b) at 0.11 AU, and at least 3 more distant planets. The polarisation of this system is very stable, showing no sign of the periodic varia...

Boo Chapple in collaboration with William Wong

Do pathogen effectors play peek-a-boo?

Epigenetics is a burgeoning field of research and many organisms are found to regulate genes in a transient (“above genetics”) way due to (temporarily) decorating DNA or proteins that associate with DNA. This can change transcription of affected genes and since such DNA modifications are reversible, the expression potential over time and generations can therefore be extremely variable. This all...

Modelling Solar-like Oscillations in Boo

Kjeldsen et al. (1995, AJ in press) recently obtained strong evidence for solar-like oscillations in the G0 IV star Boo. Here we present evolution calculations for the star and compare them with the observed oscillation frequencies. Models can be found that are consistent with the star's luminosity and eeective temperature and with the large and small frequency separations. The calculations ind...