multiple postgres processes after establishing tcp connection

Hello,
PostgreSQL 9.4.4 started in usual way

> [postgres(at)ubuntu12-vm][20150731 06:26:06]:/db2/master$ pg_ctl start -D
> /db2/master/ -l serverlog
> server starting

I can see root process for this then:

> [postgres(at)ubuntu12-vm][20150731 06:38:36]:/db2/master$ ps -ef | grep
> "bin/postgres" | grep -v grep
> postgres 5152 1 0 06:28 pts/0 00:00:00
> /opt/postgres/9.4.4/bin/postgres -D /db2/master

If only simple telnet connection started:

> [postgres(at)ubuntu12-vm][20150731 06:30:24]:/db2$ telnet 127.0.0.1 5551
> Trying 127.0.0.1...
> Connected to 127.0.0.1.
> Escape character is '^]'.

new postgres process appeared as a child of the first one.

> [postgres(at)ubuntu12-vm][20150731 06:38:42]:/db2/master$ ps -ef | grep
> "bin/postgres" | grep -v grep
> postgres 5152 1 0 06:28 pts/0 00:00:00
> /opt/postgres/9.4.4/bin/postgres -D /db2/master
> postgres 6358 5152 0 06:39 ? 00:00:00
> /opt/postgres/9.4.4/bin/postgres -D /db2/master

Is this an attempt to create new worker?
No records (presumably) in pg_stat_activity, only "invalid length of
startup packet" after closing telnet session.

--
Regards, Andrey Lizenko