Priority queue comparator on object with const member

I'm trying to implement a priority queue which uses an object which has a const member that is used to define the priority of objects in the queue. The following is a stripped down version of what I'm using

#include <vector>
#include <queue>

class Event {
public:
    Event(float _time) : time(_time) {};
    const float time;
};

struct EventComp {
public:
    bool operator()(const Event& a, const Event& b) const {
      return a.time < b.time;
    }
};

class EventQueue {
private:
    std::priority_queue<Event, std::vector<Event>, EventComp> events;
};


int main(int argc, char *argv[])
{
    EventQueue q;
}

When I try to compile (using g++ -std=c++11), I get the following error messages, which I don't quite understand.

g++ -std=c++11 events.cpp -o events
In file included from /usr/include/c++/4.8/queue:62:0,
                 from events.cpp:2:
/usr/include/c++/4.8/bits/stl_heap.h: In instantiation of ‘void std::__adjust_heap(_RandomAccessIterator, _Distance, _Distance, _Tp, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Event*, std::vector<Event> >; _Distance = long int; _Tp = Event; _Compare = EventComp]’:
/usr/include/c++/4.8/bits/stl_heap.h:448:15:   required from ‘void std::make_heap(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Event*, std::vector<Event> >; _Compare = EventComp]’
/usr/include/c++/4.8/bits/stl_queue.h:411:48:   required from ‘std::priority_queue<_Tp, _Sequence, _Compare>::priority_queue(const _Compare&, _Sequence&&) [with _Tp = Event; _Sequence = std::vector<Event>; _Compare = EventComp]’
events.cpp:15:7:   required from here
/usr/include/c++/4.8/bits/stl_heap.h:315:29: error: use of deleted function ‘Event& Event::operator=(Event&&)’
    *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __secondChild));
                             ^
events.cpp:4:7: note: ‘Event& Event::operator=(Event&&)’ is implicitly deleted because the default definition would be ill-formed:
 class Event {
       ^
events.cpp:4:7: error: non-static const member ‘const float Event::time’, can’t use default assignment operator
In file included from /usr/include/c++/4.8/queue:62:0,
                 from events.cpp:2:
/usr/include/c++/4.8/bits/stl_heap.h:321:29: error: use of deleted function ‘Event& Event::operator=(Event&&)’
    *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first
                             ^

I assume that some part of the internal structure of the priority_queue needs the move assignment operator to insert elements, but the const member seems to prevent that operator from being defined. I tried using the rule of five, but it didn't seem to work out. What do I need to add to the class definitions to get this working?

edit: I'm aware that I can remove the const qualifier from the member variable, make it private, and add an accessor member function to get the value of the variable, but I would rather have it public and const, so I'm interested in solutions which keep the member variable as it is in the example (if that is even possible).