NGC 1333

NGC 1333

Reflection nebula
An infrared image of NGC 1333 by the Spitzer Space Telescope
Observation data: J2000.0 epoch
Right ascension	03h 29m 11.3s[1]
Declination	+31° 18′ 36″[1]
Distance	967 ly (296.5 pc)[1] ly
Apparent magnitude (V)	5.6
Apparent dimensions (V)	6′ x 3′
Constellation	Perseus
Designations	Ced 16, GN 03.26.1, LBN 741[2]
See also: Lists of nebulae

NGC 1333 is a reflection nebula located in the northern constellation Perseus, positioned next to the southern constellation border with Taurus and Aries.^[3] It was first discovered by German astronomer Eduard Schönfeld in 1855.^[4] The nebula is visible as a hazy patch in a small telescope, while a larger aperture will show a pair of dark nebulae designated Barnard 1 and Barnard 2.^[5] It is associated with a dark cloud L1450 (Barnard 205). Estimates of the distance to this nebula range from 980–1,140 ly (300–350 pc).^[4]

This nebula is in the western part^[4] of the Perseus molecular cloud and is a young region of very active star formation,^[6] being one of the best-studied objects of its type.^[4] It contains a fairly typical hierarchy of star clusters that are still embedded in the molecular cloud in which they formed,^[7] which are split into two main sub-groups to the north and south. Most of the infrared emission is happening in the southern part of the nebula. A significant portion of the stars seen in the infrared are in the pre-main sequence stage of their evolution.^[6]

The nebula region has a combined mass of approximately 450 M_☉,^[4] while the cluster contains around 150 stars with a median age of a million years and a combined mass of 100 M_☉. The average star formation rate is 1×10⁻⁴ M_☉ yr^–1.^[4] Within the nebula are 20 young stellar objects producing outflows, including Herbig–Haro objects, and a total of 95 X-ray sources that are associated with known members of embedded star clusters.^[6] In 2011 researchers reported finding 30 to 40 brown dwarf objects in the cloud and in the Rho Ophiuchi cloud complex.^[8]

15 objects with a spectral type of M9 or later were discovered in NGC 1333. This spectral type corresponds to a mass of a planetar-mass object (PMO) at the age of NGC 1333. About 42% of the PMO are surrounded by a circumstellar disk, but only one out of six objects with a spectral type of L0 (about 10 M_J) or later has a disk. Scholz et al. argues that this indicates that very low mass PMOs form like planets (aka ejected planets) and not like stars (also called sub-brown dwarfs).^[9] Parker & Alves de Oliveira on the other hand argue that the distribution of PMOs in NGC 1333 follows N-body simulations of objects that form like stars and that none of the PMOs has a peculiar motion, which is predicted for ejected planets. They also note that ejected planets are hiding in this and star-forming regions.^[10]

Gallery

• 
  A small region of NGC 1333 taken by Hubble Space Telescope.^[11]
• 
  There are 5 Herbig–Haro objects (numbered 7 to 11) in NGC 1333.^[12]
• 
  NGC 1333 by the Mount Lemmon Sky Center
• 
  The region south of NGC 1333 in infrared. It shows the dark clouds Barnard 203 and 204
• 
  Perseus giant molecular cloud with star nurseries IC348 and NGC1333

References

External links

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