Palindromes in orbit

Never have I suspected to indulge myself in rbital astronomy.
Palindromic numbers are everywhere !

Open the throttle of your shuttle and travel to... Mercury
Planets and Palindromes
Well, rounded up we get 88 days...

Our Marsian colleagues nearly love palindromes too...
Find out in 'at least' how many days they orbit the Sun.
Well, rounded down we get 686 days...