ETHOS 1 is a high-latitude planetary nebula in the constellation of Lyra. This nebula is notable for possessing fast polar jets. This nebula was discovered by the Extremely Turquoise Halo Object Survey. And is also the first planetary nebula discovered by the ETHOS. ETHOS 1 is a High latitude planetary nebula. fewer than 9 percent of Galactic PNe are located at latitudes |b| ≳ 10°.
Main/Inner nebula The inner nebula features major emission lines such as O III and Hβ. Which has a diameter of ~19.4 arcsec and the inner nebula has a kinematical age of 900±100 yr kpc-1. The main nebula has a high electron temperature of 17,700±500 K. The N II emission line extends out to ~2 arcsec, which is the outermost reigon. There is also a He II line that is brighter than Hβ line, which is a indication that the nebula is density-bounded but the ionized mass of the nebula is low at ~0.002.
The polar jets ETHOS 1 has 2 polar outflows (jets) traveling at 120±10 km sec-1. The northwest jet has a velocity of 65±5 km s-1, while the southwest jet has a velocity of -55±5 km s-1. The jet has a diameter of 62.6 arcsec, and the kinematical ages of these jets is estimated to be 1750±250 yr kpc-1. The presence of O III in the jet and its relatively low Te = 12,900 K indicate that strong, radiative cooling is occurring in the post-shock region. A He I line was identified in the southwest jet.
Binary star system The central star is a close binary central star of PNe (CSPN) that shows evidence of passing through a common-envelope (CE) phase. The central star is a ∼140-kK white dwarf with a mass of ∼0.84 M⊙. making it one of the hottest and most massive post-CE central star known.
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