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Boomerang Nebula

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Boomerang Nebula
Reflection nebula
Protoplanetary nebula
image source: Hubble Space Telescope (2003)
Observation data: J2000 epoch
Right ascension12h 44m 45.45s[1]
Declination−54° 31′ 11.4″[1]
Distance1213±60[1] ly   (372±18[1] pc)
Apparent dimensions (V)1.445′ × 0.724′[1]
ConstellationCentaurus
Physical characteristics
Radius1 ly
Designations
See also: Lists of nebulae

The Boomerang Nebula is a nebula [2] located 5,000 light-years from Earth in the constellation Centaurus. 1979 Wegner and Glass discovered this nebula. [3] Modelling of measurements of outflow of the nebula indicate kelvin (K) less than cosmic microwave background radiation (cmbr), which makes the outflow the coldest natural place currently known in the Universe.[4][5][6]

Keith Taylor and Mike Scarrott called it the "Boomerang Nebula" in 1980 after observing it with the Anglo-Australian telescope at the Siding Spring Observatory. Unable to view it with great clarity, the astronomers saw merely a slight asymmetry in the nebula's lobes, suggesting a curved shape like a boomerang. The nebula was photographed in detail by the Hubble Space Telescope (HST) in 1998, revealing a more symmetrical hourglass shape.

The Boomerang Nebula is believed to be a star system evolving toward the planetary nebula phase. It continues to form and develop due to the outflow of gas from its core where a star in its late stage life sheds mass and emits starlight, illuminating dust in the nebula. Millimeter scale dust grains obscure portions of the nebula's center, so most escaping visible light is in two opposing lobes forming a distinctive hourglass shape as viewed by space telescope data on Earth. The outflowing gas is moving outwards at a speed of about 164 km/s and expanding rapidly as it moves out into space; this gas expansion results in the nebula's unusual K.

Using observations from 1994 and 1995 with the 15-metre Swedish-ESO Submillimetre Telescope in Chile, the astronomers Sahai & Nyman concluded carbon monoxide (CO) molecules produced after stellar co-absorption in a binary system of the nebula which outflow as a gas wind were less kinetically excited than the local outer space (cmbr). [a] Radiation transfer of cmbr into the CO parts [b] of the nebula wind indicated those parts only [c] must have a kelvin temperature state which is uniquely the least of any observed location in nature.[6][8] The outflow is theorized [d] as the product of [11] common-envelope evolution, [11] which was a change in the outer environment (an envelope) of the dual orbital system of the binary system.[9] The CO outflow is theorized as an environment forced out from the area of the orbital system of the larger star by the absorption of the lesser sized star into the core of the larger by terminal gravitational attraction.[11] Cooling to sub cmbr temperature is by adiabatic expansion. [12]

A succession of periodic observations from November 2011 (Atacama Large Millimeter Array) ending June 2012 (Australia Telescope Compact Array) with archived observations from HST (1998 & 2005) [12] revealed other features. [13] The nebula's visible double lobe was observed to be surrounded by a larger spherical region of cold gas seen only in sub-millimeter radio wavelengths. The nebula's outer fringes appear to be gradually warming.

As of mid-2017, it is believed that the star at the center of the nebula is a dying red giant.[14][15]

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ALMA (2017)

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Hubble

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  • This Hubble image was recorded using polarizing filters (analogous to polarized sunglasses) and color-coded by the angle associated with the polarized light.
    This Hubble image was recorded using polarizing filters (analogous to polarized sunglasses) and color-coded by the angle associated with the polarized light.
  • Red filter applied to monochromatic data
    Red filter applied to monochromatic data

Notes

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  1. ^ In the 1997 paper the researchers provide alternate quantities for the microwave background temparature of 3 K or 2.8 K.[6] In a publication of 2012 the temperature is stated as less than 2 K.[4] A more specific quantity of kelvin stated elswehere of the microwave background is 2.72548 ± 0.00057 K.[7]
  2. ^ This conclusion is reliant on previous modelling by Jura, Kahane, & Omont from 1988 and: Sahai from 1990 (Sahai & Nyman 1997 p.487 right column 2nd paragraph)
  3. ^ "We have discovered absorption of the 3 K microwave background radiation by ultracold CO gas in the Boomerang Nebula-losing mass through a fast (164 km s 1) molecular wind-This wind contains ultracold gas at temperatures below the microwave background temperature"
  4. ^ The theory uses a concept after Paczynski (1976) [9] who used V471 Tauri [10]

References

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  1. ^ a b c d e f g h i "Boomerang Nebula". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 21 October 2022.
  2. ^ "APOD: 2007 December 28 - A Beautiful Boomerang Nebula".
  3. ^ SALÉR-RAMBERG, JUSTIN (2016). "1.6 Boomerang Nebula". The outflow of the Boomerang Nebula (Physics and Astronomy MSc thesis). Gothenburg, Sweden: CHALMERS UNIVERSITY OF TECHNOLOGY. p. 7.
  4. ^ a b Sahai, R.; Vlemmings, W.; Nyman, L-A; Huggins, P. (June 2012). "Probing the Molecular Outflows of the Coldest Known Object in the Universe The Boomerang Nebula" (PDF). science.nrao.edu. National Radio Astronomy Observatory. Retrieved 24 March 2025. Model indicates Tkin < 2K
  5. ^ "Boomerang Nebula Boasts the Coolest Spot in the Universe". jpl.nasa.gov. NASA JPL. 20 June 1997. Retrieved 24 March 2025. has a temperature of about 1 Kelvin
  6. ^ a b c Sahai, Raghvendra; Nyman, Lars-Åke (1997). "The Boomerang Nebula: The Coolest Region of the Universe?". The Astrophysical Journal. 487 (2): L155 – L159. Bibcode:1997ApJ...487L.155S. doi:10.1086/310897. hdl:2014/22450. L156: We have measured a 9 mK upper limit (3 σ) on continuum emission at 89.2 and 145.6 GHz toward the Boomerang Nebula, which is much smaller than the negative temperatures seen in the CO and 13CO J 1–0 spectra, so these must result from absorption of the microwave background, requiring the excitation temperature (Tex) to be less than 2.8 K (Tbb). 3. A TWO–SHELL MODEL In shell 2 (R1,o < r < R2), Tkin < 2.8 K." "1994-1995 :2. OBSERVATIONS AND RESULTS
  7. ^ Fixsen, D. J. (2009). "THE TEMPERATURE OF THE COSMIC MICROWAVE BACKGROUND". ApJ. 707 (916): ABSTRACT. arXiv:0911.1955. doi:10.1088/0004-637X/707/2/916.
  8. ^ Cauchi, Stephen (February 21, 2003). "Coolest bow tie in the universe". The Sydney Morning Herald. Archived from the original on September 1, 2006. Retrieved February 2, 2007.
  9. ^ a b Ivanova, N.; Justham, S.; Chen, X.; De Marco, O.; Fryer, C. L.; Gaburov, E.; Ge, H.; Glebbeek, E.; Han, Z.; Li, X.-D.; Lu, G.; Marsh, T.; Podsiadlowski, P.; Potter, A.; Soker, N.; Taam, R.; Tauris, T. M.; van den Heuvel, E. P. J.; Webbink, R. F. (2013). "Common envelope evolution: where we stand and how we can move forward". The Astronomy and Astrophysics Review. 21 (59). arXiv:1209.4302. Bibcode:2013A&ARv..21...59I. doi:10.1007/s00159-013-0059-2.
  10. ^ Paczynski, B. (1976). "Common Envelope Binaries". Symposium - International Astronomical Union. 73: Structure and Evolution of Close Binary Systems. Cambridge University Press (published 14 August 2015): 75–80. doi:10.1017/S0074180900011864.
  11. ^ a b c Sahai, Raghvendra (25 September 2018). "Binary Interactions, High-Speed Outflows and Dusty Disks during the AGB-To-PN Transition - 3. The Effects of Binarity - 3.1. Large Episodic Mass-Ejections that End the AGB/RGB Phase". Galaxies. 6 ((4) Asymmetric Planetary Nebulae VII). Jet Propulsion Laboratory, California Institute of Technology. doi:10.3390/galaxies6040102.
  12. ^ a b Sahai, R.; Vlemmings, W. H. T.; Huggins, P.J.; Nyman, L.-Å.; Gonidakis, I. (10 November 2013). "ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA". The Astrophysical Journal. 777 (92): 1. doi:10.1088/0004-637X/777/2/92. adiabatic expansion: 4. DISCUSSION." "2011-2012 & HST: 2. OBSERVATIONS
  13. ^ "ALMA reveals ghostly shape of 'coldest place in the universe'". Phys.Org. Science X (sciencex.com). Retrieved 25 October 2013.
  14. ^ Sahai (May 31, 2017). "The Coldest Place in the Universe: Probing the Ultra-Cold Outflow and Dusty Disk in the Boomerang Nebula". The Astrophysical Journal. 841 (2). The American Astronomical Society: 110. arXiv:1703.06929. Bibcode:2017ApJ...841..110S. doi:10.3847/1538-4357/aa6d86.
  15. ^ Archived at Ghostarchive and the Wayback Machine: "Astronomers solved the 22-year-long mystery behind the coldest place in the universe". YouTube. 19 June 2017.
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