SQL & PL/SQL

i have following code in my practice / examples, what if i want to add department_name column to return from this pipelined table function which is not part of employees table, please help how to achieve this?

-- step # 1 object type to match employees record
create or replace type hr.emp_scalar_type as object
 (EMPNO NUMBER(4) ,
  ENAME VARCHAR2(30),
  JOB VARCHAR2(10),
  MGR NUMBER(6),
  HIREDATE DATE,
  SAL NUMBER(8, 2),
  COMM NUMBER(4, 2),
  DEPTNO NUMBER(4)
 )
/
-- step # 2 table type of employees records
create or replace type hr.emp_table_type as table of hr.emp_scalar_type
/
-- step # 3 pipelined function
create or replace function hr.get_emp( p_deptno in number )
 return emp_table_type
 PIPELINED
 as
   TYPE EmpCurTyp IS REF CURSOR RETURN hr.employees%ROWTYPE;
   emp_cv EmpCurTyp;
   l_rec  hr.employees%rowtype;
 begin
   open emp_cv for select * from hr.employees where department_id = p_deptno;
   loop
     fetch emp_cv into l_rec;
     exit when (emp_cv%notfound);
     pipe row( emp_scalar_type( l_rec.employee_id, LOWER(l_rec.last_name),
         l_rec.job_id, l_rec.manager_id, l_rec.hire_date, l_rec.salary, 
         l_rec.commission_pct, l_rec.department_id ) );
   end loop;
   return;
 end;
/


-- step # 4 execute query  
select * from table(hr.get_emp(20));
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      201 hartstein  MK_MAN           100 17-FEB-04      13000                    20
      202 fay        MK_REP           201 17-AUG-05       6000                    20

regards