Run Thunderbird inside the system tray

I want to see Thunderbird application minimized inside the system tray rather than closing it when close button is pressed. Is it possible to do that?

Just same as Riot instant messaging application is running inside the system tray after close button is pressed.

Thunderbird version: Thunderbird 60.8.0
OS: Debian Stretch (v9.9)
Desktop environment: GNOME

I see you are using GNOME – an outdated version of GNOME. In newer GNOME versions that “feature” is deprecated and actually removed anyway.
See this article for why/how/when, the reasons etc.:

That said, you can extensions to re-add this somewhat in later versions, too.

Anyway about your actual question: It may be possible, but I am not sure how. (also, as said, GNOME devs do not think these little icons all over the screen make sense anyway – they consider notifications etc./other desktop integration the better feature for that)