for(i = 0; i < 5; i++) {
    console.log( i + 'estrelas!');
}

<ion-icon *ngFor="1 to 5" name="star"></ion-icon>

<div *ngFor="#hero of heroes">{{hero.fullName}}</div>

<i [ngClass]="{
    'ion-android-star-outline': valorEstrela < 1,
    'ion-android-star': valorEstrela >= 1}">
</i>
<i [ngClass]="{
    'ion-android-star-outline': valorEstrela < 2,
    'ion-android-star': valorEstrela >= 2}">
</i>
<i [ngClass]="{
    'ion-android-star-outline': valorEstrela < 3,
    'ion-android-star': valorEstrela >= 3}">
</i>
<i [ngClass]="{
    'ion-android-star-outline': valorEstrela < 4,
    'ion-android-star': valorEstrela >= 4}">
</i>
<i [ngClass]="{
    'ion-android-star-outline': valorEstrela < 5,
    'ion-android-star': valorEstrela >= 5}">
</i>