Are angular class properties "reactive" by default?

Question

If I have an angular class, e.g:

export class ParameterObject {
  _location;
  _searchParameters;
  _selection;
}

and I update the properties in some other class or part of my angular code

const p = new ParameterObject();
p._location ="Berlin";

Will that parameterObject get updated in my other components as well, or will I have to .next(newValue) all properties as Observables of some kind? Because I thought that components is some kind of "singleton" by default if I import it from a central class into other components, or not? so there should be just one updated class throughout my whole app?