Chandra ACIS-S imaging spectroscopy of anomalously faint X-ray emission from Comet 103P/Hartley 2 during the EPOXI encounter

► At LX = 1.1 × 1014 erg s−1, 103P was the 3rd faintest comet ever detected in the X-ray. ► Its X-ray spectrum varied as the solar wind changed between slow, hot and cold, fast states. ► 103P produced collisionally thin to CXE morphology modulated by cometary rotation. ► The X-ray emission was unusual due to extended coma emission of gas in this hyperactive comet.