NGC 6210

NGC 6210
Emission nebula
Planetary nebula
A Hubble Space Telescope (HST) image of NGC 6210
Observation data: J2000 epoch
Right ascension16h 44m 29.51960s[1]
Declination+23° 47′ 59.4913″[1]
Distance5.4 ± 1.3 kly (1.7 ± 0.4 kpc)[2] ly
Apparent dimensions (V)40″ × 30″[2]
ConstellationHercules
Physical characteristics
Radius0.5 ly
DesignationsPN G043.1+37.7, BD+24° 3048, HD 151121, IRAS 16423+2353, NGC 6210[3]
See also: Lists of nebulae

NGC 6210, sometimes also known as the Turtle Nebula,[4] is a planetary nebula located in the constellation Hercules, approximately 5.4 ± 1.3 kly from the Sun.[2] It is positioned about 38° above the galactic plane at a vertical distance of about 3.3 kilolight-years (1 kpc) and thus has little extinction from intervening interstellar dust.[5] This object was first recorded as a star-like feature by Joseph Lalande on March 22, 1799. However, credit for the discovery of a nebula goes to Wilhelm Struve in 1825. John L. E. Dreyer described it as, "a planetary nebula, very bright, very small, round, disc and border".[6]

This nebula is "very amorphous and irregular" in shape, but forms a rough ellipsoid.[5] It consists of two parts; a bright inner region filled with arches and filaments spanning 13″ × 16", and a larger and fainter outer volume that has a pair of "tubular" structures. The inner region has an expansion velocity ranging over 19–24 km/s.[2] The emission from the outer part of the nebula is only about 1% of the total.[5]

The central star has an apparent visual magnitude of 12.66 and the spectrum matches a hydrogen-rich star of type O(H). It has an estimated temperature of 65,000 K. The abundances of the nebula suggest a low initial mass for the central star, probably ~0.9 M☉.[5] Outflow from this star has been measured with velocities of 2,180 km/s, and the estimated mass loss rate is 2.2×10−9 M☉ yr−1. There appears to be a collaminated jet feature to the northwest, suggesting the central star is ejecting material along two and possibly four such directions.[7]

  1. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Bohigas2015 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  4. ^ Stoyan, Ronald; Schurig, Stephan (2014). interstellarum Deep Sky Atlas. Erlangen: Cambridge University Press; Oculum-Verlag GmbH. ISBN 978-1-107-50338-0. OCLC 920437579.
  5. ^ a b c d Cite error: The named reference Pottasch2009 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference cseligman was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Phillips1996 was invoked but never defined (see the help page).