Trying to update. Quick Question

I have an Imac 5 that apparently cant handle OS El Capitan, so I wanted to ask what is the most recent OS that I can actually handle. Heres some additonal details on the PC.

Model Name: iMac

Model Identifier: iMac5,1

Processor Name: Intel Core 2 Duo

Processor Speed: 2 GHz

Number Of Processors: 1

Total Number Of Cores: 2

L2 Cache: 4 MB

Memory: 1 GB

Bus Speed: 667 MHz

Boot ROM Version: IM51.0090.B09

SMC Version (system): 1.8f2

Serial Number (system): W8****VUX

Hardware UUID: 00000000-0000-1000-8000-0019E34138FD

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