The Frosty Leo Nebula, also known as IRAS 09371+1212, is a protoplanetary nebula located approximately 3,000 light-years from Earth in the constellation Leo. Despite their name, protoplanetary nebulae are not related to planets but are formed from material ejected by their aging central stars.
Characteristics
- Structure: The Frosty Leo Nebula features a complex structure, including a spherical halo, a disc around the central star, lobes, and large loops. This intricate shape suggests complex formation processes, possibly involving a second, unseen star.
- Composition: It is rich in water ice grains, which is unusual for such nebulae. This characteristic contributed to its nickname “Frosty Leo”.
- Symmetry and Shape: The nebula has an hourglass shape with two lobes separated by an almost edge-on dust ring. It is notable for its point reflection symmetry, a rare trait among protoplanetary nebulae.
- Molecular Envelope: The nebula’s molecular envelope is expanding at approximately 25 km/s.
Observation
- The Frosty Leo Nebula was first identified in the IRAS survey due to its cold infrared color temperatures and sharp maximum at 60 micrometers. It was named “Frosty Leo” due to its unusual infrared spectrum and the presence of crystalline ice.
- Observations have been conducted using various methods, including near-infrared imaging polarimetry in the J, H, and K′ bands.
Significance
Protoplanetary nebulae like Frosty Leo are precursors to the planetary nebula phase, where the nebula’s gas becomes illuminated by radiation from the central star. Their brief lifespans and rarity make them important subjects for astronomers studying stellar evolution.
References
Image: The frosty Leo Nebula
https://esahubble.org/images/potw1149a/
The near-infrared polarization of the pre-planetary nebula Frosty Leo
Serrano Bernal, E & Sabin, Laurence & Luna, Abraham & Rangaswamy, Devaraj & Mayya, Y. & Carrasco, Luis. (2020)
Monthly Notices of the Royal Astronomical Society. 495. 2599-2606. 10.1093/mnras/staa1291.
Circular Astronomy 