This suffers the same problem which I've been struggling with for the vector add / subtract as well, which is loss of the metadata attributes like `self.lat` or `self.delta_ut1_utc` in the creation of `tm`.

I have an idea to enhance `replicate` with `jd1` and `jd2` attributes so that the code would like more like (sans `is_scalar` validation):
```
def __getitem__(self, item):
    jd1 = self._time.jd1[item]
    jd2 = self._time.jd2[item]
    tm = self.replicate(jd1=jd1, jd2=jd2)
    return tm
```