8 SMR - planet connection

Several of the nearby SMR star candidates listed by Taylor (1996, Table 4) have been found to harbour planets. In particular, the planet-bearing stars HD 75732, HD 145675, and HD 217014 are included in Taylor's list of 29 SMR class IV-V star candidates. Not all the stars in his list have been searched for planets as of yet, so the fraction of SMR star candidates with planets may increase. Butler et al. (2000) provide independent confirming evidence for a preponderance of planets among metal-rich stars; they note that of their 600 Keck targets, half of which are metal-poor, 2 planets have been found around metal-poor stars and 10 around metal-rich stars. Also, several planet-bearing stars not in Taylor's list have recently been found to be likely SMR stars. Examples in this group include HD 120136, HD 217107, and HD 210277 (Gonzalez 2000). It appears that the Doppler planet search method is also an efficient detector of new SMR star candidates!

Gonzalez et al. (1999) suggested that BD $-10{\hbox{$^\circ$ }} 3166$ be searched for planets on the basis of its similarity to HD 75732 and HD 145675 (similar $T_{\rm eff}$ and [Fe/H]). Butler et al. (2000) reported on the detection of a planet around BD $-10{\hbox{$^\circ$ }} 3166$, which they had placed on their monitoring program as a result of Gonzalez et al.'s suggestion. Another star, HD 89744, was suggested to Geoff Marcy as a planet-bearing candidate by one of us (G.G.) on the basis of its high [Fe/H] and low [C/Fe]. Sylvain et al. (2000) announced the discovery of a planet around this star (note: they began observing this star about 2 years before Gonzalez's prediction). The successful prediction of the presence of planets around two stars provides strong independent confirming evidence of the planet - SMR star connection. The low [C/Fe] values seen among stars with planets is the first convincing evidence of a trend with abundance ratios. The physical significance of this trend is not yet known.