There is an ongoing debate on whether hot jupiter hosts are more likely to be found in wide binaries with separations of \gtrsim 100 AU .
In this paper , we search for comoving , very wide companions with separations of 10 ^ { 3 } -10 ^ { 4 } AU for hot jupiter hosts and main-sequence contact binaries in Gaia DR2 , and compare the very wide companion fractions with their object-by-object-matched field star samples .
We find that 11.9 \pm 2.5 % of hot jupiter hosts and 14.1 \pm 1.0 % of contact binaries have companions at separations of 10 ^ { 3 } -10 ^ { 4 } AU .
While the very wide companion fraction of hot jupiter hosts is a factor of 1.9 \pm 0.5 larger than their matched field star sample , it is consistent , within \sim 1 \sigma , with that of matched field stars if the matching is only with field stars without close companions ( within \sim 50 AU ) as is the case for hot jupiter hosts .
The very wide companion fraction of contact binaries is a factor of 3.1 \pm 0.5 larger than their matched field star sample , suggesting that the formation and evolution of contact binaries are either tied to or correlated with the presence of wide companions .
In contrast , the weak enhancement of very wide companion fraction for hot jupiter hosts implies that the formation of hot jupiters is not as sensitive to those environment properties .
Our results also hint that the occurrence rates of dual hot jupiter hosts and dual contact binaries may be higher than the expected values from random pairing of field stars , which may be due to their underlying metallicity and age dependence .