Southern Crab Nebula

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Fog
Henize 2-104
Image taken by the Hubble Space Telescope, 2019
Image taken by the Hubble Space Telescope , 2019
AladinLite
Constellation centaur
Position
equinox : J2000.0
Right ascension 14h 11m 52.1s
declination -51 ° 26 ′ 24 ″
Appearance
Central star
designation V852 Cen 
Apparent brightness 6.3-6.7 mag 
Physical data
history
discovery Black, Aspin, Lutz
Date of discovery 1989
Catalog names
 PK  315 + 09 1 • PN G315.4 + 09.4 •  ESO  221-31 •

The Southern Crab Nebula, or Hen 2-104, is a bipolar nebula that is located in the constellation Centaurus when viewed from Earth and is several thousand light-years from Earth. Its central object is a symbiotic star consisting of a Mira star and a white dwarf .

The nebula presumably consists of material repelled by the Mira, which is ionized by the high-energy radiation of the white dwarf and thus made to glow. The mass of the ionized nebula is estimated to be about a tenth of the solar mass , which is significantly higher than that of other symbiotic nebulae . The high loss of mass indicates that the Mira is in a highly developed stage, close to the asymptotic giant branch .

The adjective south distinguishes Hen 2-104 from the Crab Nebula , which is located in the northern sky .

Discovery and Exploration

Photo of the center, Hubble Space Telescope, 1999

Hen 2-104 was discovered in 1967 by Karl Henize as a point source and classified as a planetary nebula due to its emission lines . It was not until 1989 that the extensive nebula was discovered and named the Southern Crab Nebula. The nebula was found with the 2.2 m telescope of ESO on La Silla (Chile), but the images from the Hubble Space Telescope from 1999 show much more details, e.g. a. that the center of the nebula consists of a pair of stars consisting of a red giant and a white dwarf.

The distance from Hen 2-104 is difficult to determine. Estimates obtained by various methods are on the order of 1 to 8  kpc . Most recently, Corradi et al. with the help of the period-brightness relationship of Mira stars a distance of 4.4 kpc and Santander-García et al. estimated the distance to be (3.5 ± 0.7) kpc for the jets and (3.1 ± 0.9) kpc for the outer shells using a determination of the expansion parallax using the Hubble telescope. Using Gaia , an optical parallax of 0.2089 ± 0.0529 milli-arcseconds was determined, corresponding to 3.8-6.4 kpc.


literature

Web links

Individual evidence

  1. ↑ SIMBAD query
  2. ↑ General Catalog of Variable Stars ( Vizier )
  3. ^ A b M. Santander-García et al .: Hen 2-104: a close-up look at the Southern Crab. In: Astronomy & Astrophysics Vol. 485, No. 1 (2008), P. 120, doi : 10.1051 / 0004-6361: 20079212
  4. ^ KG Henize: Observations of Southern Planetary Nebulae . In: The Astrophysical Journal, 14 (1967), 125, doi : 10.1086 / 190151
  5. ^ HE Schwarz et al .: He 2-104 - A symbiotic proto-planetary nebula? In: The Astrophysical Journal, 344 (1989), L29, doi : 10.1086 / 185523
  6. ↑ a b R.LM Corradi et al .: The Southern Crab from a New Perspective. In: The Astrophysical Journal Vol. 553, No. 1 (2001), p. 216, doi : 10.1086 / 320665
  7. ↑ S. Kimeswenger, D. Barría: Planetary nebula distances in Gaia DR2. In: Astronomy & Astrophysics , 616 (2018), L2, doi : 10.1051 / 0004-6361 / 201833647 , bibcode : 2018A & A ... 616L ... 2K