DD Microscopii, also known as CD−43°14304, is a binary star system in the constellation Microscopium. The system has a combined average apparent magnitude around 11, making it readily visible in telescopes but not to the naked eye. It is thought to be at a distance of one or two thousand parsecs, although parallax measurements place the system at a distance of around 30,000 light years.
It is a symbiotic star system composed of an orange giant with a class of either K2 III or K5/M0 IIIe. Both stellar classifications of the primary indicate a red giant, but one has a regular spectrum while the other shows an evolved star with the characteristics of a K5 and M0 giant star plus emission lines in its spectrum. The secondary is a white dwarf in close orbit, ionizing the stellar wind of the larger star. The giant star and white dwarf both take about 4 years to orbit each other.
The primary has an enlarged radius of 103 R☉ and an effective temperature of 3,941 K, giving a red hue when viewed through a telescope. DD Microscopii is extremely metal deficient, with an iron abundance only 12% of the Sun, and spins leisurely with a projected rotational velocity lower than 3 km/s. The star system has its origin in the galactic halo of the Milky Way as indicated by the high galactic latitude. DD Microscopii is cataloged as a Z Andromedae variable, a type of symbiotic binary with occasional outbursts. It fluctuates between magnitudes 11.0 and 11.7 over a span of almost 400 days.
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