ETHOS 1 is a high-latitude planetary nebula in the constellation of Lyra. This nebula is notable for possessing fast polar jets and was discovered by the Extremely Turquoise Halo Object Survey. It is also the first planetary nebula discovered by ETHOS.
ETHOS 1 is a High latitude planetary nebula. fewer than 9 percent of Galactic PNe are located at latitudes |b| ≳ 10°.
The inner nebula features major emission lines such as O III and Hβ. The inner nebula also has a diameter of ~19.4 arcsec with the kinematical age is 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 clear indication that the nebula is density-bounded even though the ionized mass of the nebula is low at ~0.002.
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 jets has a diameter of 62.6 arcsec with kinematical ages of approximately 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 . making it one of the hottest and most massive post-CE central star known.
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