Objection 1. It would seem that an aureole is also due to the body. For the essential reward is greater than the accidental. But the dowries which belong to the essential reward are not only in the soul but also in the body. Therefore there is also an aureole which pertains to the accidental reward.
Objection 2. Further, punishment in soul and body corresponds to sin committed through the body. Therefore a reward both in soul and in body is due to merit gained through the body. But the aureole is merited through works of the body. Therefore an aureole is also due to the body.
Objection 3. Further, a certain fulness of virtue will shine forth in the bodies of martyrs, and will be seen in their bodily scars: wherefore Augustine says (De Civ. Dei xxii): "We feel an undescribable love for the blessed martyrs so as to desire to see in that kingdom the scars of the wounds in their bodies, which they bore for Christ's name. Perchance indeed we shall see them, for this will not make them less comely, but more glorious. A certain beauty will shine in them, a beauty, though in the body, yet not of the body but of virtue." Therefore it would seem that the martyr's aureole is also in his body; and in like manner the aureoles of others.
On the contrary, The souls now in heaven have aureoles; and yet they have no body. Therefore the proper subject of an aureole is the soul and not the body.
Further, all merit is from the soul. Therefore the whole reward should be in the soul.
I answer that, Properly speaking the aureole is in the mind: since it is joy in the works to which an aureole is due. But even as from the joy in the essential reward, which is the aurea, there results a certain comeliness in the body, which is the glory of the body, so from the joy in the aureole there results a certain bodily comeliness: so that the aureole is chiefly in the mind, but by a kind of overflow it shines forth in the body.
This suffices for the Replies to the Objections. It must be observed, however, that the beauty of the scars which will appear in the bodies of the martyrs cannot be called an aureole, since some of the martyrs will have an aureole in which such scars will not appear, for instance those who were put to death by drowning, starvation, or the squalor of prison.
Source: Summa Theologica (New Advent)