Stingray Nebula

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Stingray Nebula
Emission nebula
Planetary nebula
Stingraynebula.jpg
Hubble Space Telescope photograph of the nebula (Credit: M. Bobrowsky and NASA)
Observation data: J2000 epoch
Right ascension17h 16m 21.071s[1]
Declination−59° 29′ 23.64″[1]
Distance18×103 ly   (5.6×103[2] pc)
Apparent magnitude (V)10.75[1]
Apparent dimensions (V)1″.6[2]
ConstellationAra
Physical characteristics
Radius0.08[2] ly
Absolute magnitude (V)−3.0[a]
DesignationsPN G331.3-12.1,[1]
Hen 3-1357[1]
See also: Lists of nebulae

The Stingray Nebula (Hen 3-1357) is the youngest known planetary nebula.[2] The Stingray is located in the direction of the southern constellation Ara (the Altar), and is located 18,000 light-years away. Although it is some 130 times the size of the Solar System, the Stingray Nebula is only about 1/10 the size of most other known planetary nebulae. The central star of the nebula is the fast-evolving star SAO 244567. Until approximately forty years ago, it was observed on Earth as a preplanetary nebula in which the gas had not yet become hot and ionized.

The image of the nebula shows how the older outer shells of gas are acting as a collimator for the more recent gas outflow from the central star—an important observation, as this process has not been well understood.[citation needed]

History[]

Prior to the discovery of the nebula, its central star was known as He 3-1357, which Karl Gordon Henize classified as an A or B type Hα emission line star in 1967. It was observed in 1971 to be a preplanetary nebula when it seemed to be an asymptotic giant branch B1 supergiant. Planetary nebula emission lines were identified in this star in 1989 by the International Ultraviolet Explorer.[3] As the nebula would be newly formed and very small, ground-based observations were not able to resolve it; so Bobrowsky observed it with the Hubble Space Telescope, discovering the nebula, which he named the "Stingray Nebula".[2]

In 1995 the central planetary nebula nucleus was observed as a DA white dwarf, having seemingly faded by a factor of three between 1987 and 1995. The white dwarf has an estimated mass of 0.6 M☉ and luminosity of 3000 L☉[4] and has an observed companion star separated by 0.3 arcsec. Nebula mass is estimated as 0.015 M☉.

In 1998 Bobrowsky et al. described how the Hubble Space Telescope observations revealed a 17th-magnitude companion to the Stingray's 15th-magnitude central star.[5]

The central star is unusual in that it has brightened and faded over a period of 20 years. Its temperature went up by 40,000 °C. An explanation for this is that it has undergone a helium flash.[6]

In January 2021 NASA discovered that the nebula is fading.[7] In a NASA statement a team member, Martín A. Guerrero of the Instituto de Astrofísica de Andalucía in Granada, Spain, said: "This is very, very dramatic, and very weird. What we're witnessing is a nebula's evolution in real time. In a span of years, we see variations in the nebula. We have not seen that before with the clarity we get with this view."[8]

Two images captured in 1996 and 2016 show the nebula dimming and changing shape.

Notes[]

  1. ^ 10.75 apparent magnitude − 5 * (log10(5.6 kpc distance) − 1) = −3.0 absolute magnitude

References[]

  1. ^ Jump up to: a b c d e SIMBAD (15 January 2007). "Results for Stingray Nebula". SIMBAD, Centre de Données Astronomiques de Strasbourg.
  2. ^ Jump up to: a b c d e Bobrowsky, M. (1994). "Narrowband HST imagery of the young planetary nebula Henize 1357". The Astrophysical Journal. 426: L47–L50. Bibcode:1994ApJ...426L..47B. doi:10.1086/187336.
  3. ^ Parthasarathy, M.; Garcia-Lario, P.; Pottasch, S. R.; Manchado, A.; Clavel, J.; de Martino, D.; van de Steene, G. C. M.; Sahu, K. C. (1993). "SAO 244567: a post-AGB star which has turned into a planetary nebula within the last 40 years". Astronomy & Astrophysics. 267: L19–L22. Bibcode:1993A&A...267L..19P.
  4. ^ Parthasarathy, M. (2000). "Birth and early evolution of planetary nebulae". Bulletin of the Astronomical Society of India. 28: 217–224. Bibcode:2000BASI...28..217P.
  5. ^ Bobrowsky, M.; Sahu, K. C.; Parthasarathy, M.; García-Lario, P. (1998). "Birth and early evolution of a planetary nebula". Nature. 392 (6675): 469–471. arXiv:astro-ph/9804022. Bibcode:1998Natur.392..469B. doi:10.1038/33092.
  6. ^ "Astronomers observe star reborn in a flash". Phys.org. 13 September 2016. Retrieved 18 September 2016.
  7. ^ Mathewson, Samantha (8 January 2021). "The Stingray nebula is fading fast, Hubble telescope photos reveal". Space.com. Retrieved 8 January 2021.
  8. ^ Jenner, Lynn (30 November 2020). "Hubble Captures Unprecedented Fading of Stingray Nebula". NASA. Retrieved 8 January 2021.

External links[]

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