Karl Gottfried von Leitner wrote a poem about that, and in the last year of his life, Franz Schubert set it to music. Leitner handles it indirectly, and even if you don't know German, you can simply feel the passage where the narrator speaks of his late wife's presence in the room, thanks to Schubert's musical gift.
Someone posted a picture on FB recently. It had a figure of a kid lookng at the stars. The caption said, “maybe stars are just openings where our loved ones look down at us.”. A nice thought, anyway.