<td>Cell_Text<div class="star">☆</div></td>

div.star
{
 float:right;
 margin-top:-10px;
}

div.star
{
position:absolute;
top:somepx;
right:somepx;
}

td { position: relative; }
td .star { position: absolute; top: 0; right: 0; }

td {
    /* required in order to position the element relative to the cell */
    position: relative;
}

td .star {
    position: absolute;
    top: 0;
    right: 0;
}

float:right;

color: /* your desired color */