1. the devas from bhramhaa onwards – all devas, their consorts and there subordinates!
2. The risis who gave us the vedas mentioning each division of veda and their risis starting from veda vyasa, all risis, their consorts and there subordinates!
3. All the pitrus starting from soman and yama angiraswan all pitrus, their consorts and there subordinates!
Tharpanam means literally pleasing someone. This is done by remembering the person and pouring water on the hand in a prescribed way. It is best that the water is poured on the hand and it reaches the earth. If such a situation is not possible it can be collected in a vessel and later on poured on the earth.
If for some reason the daily puja has not taken place till now it is to be done.
Next comes the pancha maha yagna.
It is basically offering food to 1. devas, 2. pitrus, 3.mankind, 4. the rest of the living being from worms onwards! The brahmins have to do a ritual called vaishvadevam. There is a difference of opinion as to what pancha maha yagna; one school says what has been said above is what it is; another school says it is something more. Anyway....
To offer at least one twig (samith) in fire (agni) is deva yagna.
Feeding pitrus -usually offering to crows- is pitru yagna.
Offering to the non visible beings called boothas is bootha yagnam.
Offering food to people is manushya yagnam.
The concept of vaishvadevam comes from recognising that while we do our routine house hold work we unknowingly kill several things.
The fireplace, the pestle and mortar, grinding stone, winnowing fan, and the water vessel are places that it can happen. Though we normally don't use things much nowadays and they are out of fashion think of the gas/electrical stove, grinder, mixie and water purifier. When we use these things some insects microbes etc. Will die. As an atonement wee do this karma.
Why this is only for brahmins? That is because unlike other classes he is expected to have jeeva karunya (love for all life forms) as a primary attitude.
(more to come....)