AS 314
A protoplanetary nebula reclassified from hypergiant to post-AGB star.
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AS 314, also designated V452 Scuti, is a protoplanetary nebula in the constellation Scutum. It was once believed to be a white hypergiant star or luminous blue variable, but later reclassified as a post-AGB star. With an apparent magnitude of 9.85, it is observable with small telescopes.
Quick Facts
- Apparent magnitude
- 9.85
- Constellation
- Scutum
- Variable star designation
- V452 Scuti
- Radius (early incorrect estimate)
- 200 times solar
Facts from the source article.
Lore & Background
AS 314 was identified as a variable star in 1996 through analysis of Hipparcos data, receiving the variable star designation V452 Scuti in 1999. It remained poorly studied until the year 2000, when Miroshnichenko et al. produced an incorrect distance estimate of about 10 kiloparsecs, along with correspondingly high luminosity, radius, and initial mass. The star was also estimated to be losing mass through a very strong stellar wind.
The object exhibits an infrared excess, indicating a circumstellar envelope of dust, and has been considered a candidate luminous blue variable rather than a bona fide one. However, the Hipparcos parallax and proper motions are large, implying a much closer and less luminous star. This measurement was later confirmed by the Gaia mission, leading to the reclassification of AS 314 as a post-AGB star.
Reader's Guide
AS 314's significance lies in its dramatic reclassification from a presumed white hypergiant or luminous blue variable to a post-AGB star, a shift driven by precise astrometric data from Hipparcos and later confirmed by Gaia. This correction resolved a major discrepancy in the object's estimated distance and luminosity, illustrating the importance of accurate parallax measurements in stellar astrophysics. The object's infrared excess and circumstellar dust envelope mark it as a protoplanetary nebula in transition, offering a window into the late stages of stellar evolution.
Its candidacy as a luminous blue variable, though not confirmed, highlights the historical ambiguity surrounding its nature. For amateur astronomers, its apparent magnitude of 9.85 makes it accessible with small telescopes, while its variable star designation underscores its ongoing photometric interest. The legacy of AS 314 is a cautionary tale about the pitfalls of relying on indirect distance estimates and a testament to the power of space-based astrometry in refining our understanding of stellar populations.
More in Emission, Dark and Reflection Nebulae
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: AS 314 (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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