Sun

The Beanstalk peg maintenance mechanism requires a protocol-native timekeeping mechanism and regular code execution on Ethereum. The Sun keeps time on the Farm in Seasons and incentivizes cost-efficient and timely calling of the gm function.

Beanstalk adjusts itself to return the Bean price to its value peg at the beginning of every Season. Each Season is ~1 hour long. The first Season began when Beanstalk was deployed on August 6, 2021.

The exact beginning of each Season may vary as Seasons do not begin until the gm function has been called through an Ethereum transaction. The first transaction that successfully calls the gm function after the top of each hour UTC begins a new Season. Beanstalk only accepts one gm function call per Season.

Beanstalk covers the cost of calling the gm function by awarding the sender of an accepted gm function call with newly minted Beans. To encourage regular gm function calls even during periods of congestion on Ethereum while minimizing cost, the award is based on an approximation of the cost to call the gm function in Beans in the current block and compounds 1% every additional second that elapses for 300 seconds (see Section 4 of the whitepaper for complete formulas).

Upon acceptance of the gm call, the Sun:

1. Increments the Season number;

2. Calculates deltaB, the sum of the time and liquidity weighted average shortage or excess Beans across liquidity pools on the Oracle Whitelist;

3. Changes the Maximum Temperature if necessary and checks for Flood;

4. Sets the initial Soil supply;

5. Mints Beans if necessary; and

6. Awards Beans to the address that successfully called the gm function.

Minting Whitelist

To be included in the calculation of deltaB, a liquidity pool must be on the Minting Whitelist.

Additional liquidity pools may be added to the Minting Whitelist via Beanstalk governance. In order for a liquidity pool to be added to the Minting Whitelist, Beanstalk requires:

1. The pool address; and

2. A function to calculate the liquidity and time weighted average shortage or excess of Beans in the pool (see Section 14.6 of the whitepaper for complete formulas).

Current Minting Whitelist

Name	Address
BEAN:3CRV Curve pool	0xc9C32cd16Bf7eFB85Ff14e0c8603cc90F6F2eE49
BEAN:ETH Well	0xBEA0e11282e2bB5893bEcE110cF199501e872bAd