Stars can't be memories

**Describe the bug**
If you enter a system and leave it, the star always shows up as "current" in its report; it's never listed as a memory.

**To Reproduce**
Steps to reproduce the behavior:
1. Enter system with star
2. Leave system
3. Wait a turn or two
4. Check the star report

**Expected behavior**
Star is listed as "Memory from 2 turns ago" or whatever

**Actual behavior**
Star is listed as "Current"

**Screenshots**