NGC 2112

Posted on by ltb593

Behold! NGC 2112, a mesmerizing open cluster of intermediate age located in the Orion constellation, with celestial coordinates of Right Ascension: 05h 53m 44s and Declination: +00° 24’ 38”. William Herschel discovered it in 1785, and it is estimated to be approximately 2.0 +/- 0.3 Gyr old. The cluster has a diameter of around 18 arcmin and contains around 100 stars with varying magnitudes, affecting its overall brightness. NGC 2112 is located about 940 parsecs away from Earth, and its radial velocity is 30.861 km/s.

Although NGC 2112 has not been fully scrutinized, astronomers find it captivating to study the chemical evolution of the galactic disc since it is located in the Milky Way galaxy, has low metal abundance and is suspected to be old. According to Carraro, Ng & Portinari (1998), NGC 2112’s combination of suspected age and low metal abundance makes it intriguing to study.

Located in the constellation of Orion, NGC 2112 is part of the Orion OB1 association, a large stellar association that includes several other open clusters, such as NGC 1980 and NGC 2141. The Orion OB1 association is estimated to be about 10 million years old and is one of the nearest regions of recent star formation to Earth.

Observations of NGC 2112 have also led to the discovery of brown dwarfs, which are objects that are too massive to be considered planets but not massive enough to undergo sustained hydrogen fusion in their cores like stars. In 2000, a team of astronomers discovered four brown dwarf candidates in the cluster using deep infrared imaging.

The existence of brown dwarfs in NGC 2112 and analogous open clusters carries significant weight in our comprehension of stellar genesis and the nascent development of planetary systems. Brown dwarfs are thought to form in a similar way to stars, through the gravitational collapse of molecular clouds, but their low mass prevents them from achieving the high temperatures and pressures required for sustained nuclear fusion.

Richtler (1985) conducted the first study of NGC 2112 by obtaining photographic BV photometry for 80 stars down to V = 15. He estimated that NGC 2112 had a reddening of approximately 0.5 mag and was situated around 800 pc away from the Sun. Later Richtler & Kaluzny (1989) studied 500 stars in a field of 200 arcmin and concluded that NGC 2112 was between 3 to 5 billion years old, had a reddening of E(B−V) = 0.60 mag, and was located 700 to 800 parsecs from the Sun, with a metallicity of -1.

Using high-resolution spectroscopy, Brown et al. (1996) determined that the metal abundance of NGC 2112 was [Fe/H] = -0.15, slightly lower than the solar value. Despite varying estimates of the distance and age of NGC 2112, it is clear that more research is needed to understand the metallicity and formation history of the cluster fully.

Although blue stragglers are not present in NGC 2112, there may be other exciting objects and phenomena worth studying, such as variable stars, young stellar objects, and star-forming regions. One such object is the NGC 2112 reflection nebula, which is a blue reflection nebula illuminated by the light of a young star or stars in the cluster. The nebula is relatively faint, and its properties are still uncertain and the subject of ongoing study by astronomers.

NGC 2112 is not only a remarkable cluster to study in terms of its chemical evolution and formation history, but it also serves as a valuable tool for testing and refining our understanding of stellar evolution. For instance, the presence of white dwarfs in NGC 2112 provides a means of calibrating models of the final stages of low-mass star evolution. By studying the white dwarf cooling sequence, astronomers can test the accuracy of theoretical models and gain insights into the internal structures and compositions of the progenitor stars.

NGC 2112’s placement within the Orion constellation marks it as a primary objective for forthcoming observations using advanced space telescopes, like the James Webb Space Telescope (JWST) and the Nancy Grace Roman Space Telescope. These technological marvels promise unmatched acuity and sensitivity, affording researchers the opportunity to explore the cluster’s configuration and attributes with greater precision. Through such scrutiny, the scientific community could uncover groundbreaking revelations and enhance our appreciation of the origination and progression of stars and star clusters, both within our galaxy and beyond.

However, scrutinizing NGC 2112 poses a series of obstacles for astronomers, including the subdued surface brightness of the reflection nebula, the proximity of luminous stars, and uncertainties regarding membership to the star cluster. Nonetheless, astronomers are using various methods to gain a far more comprehensive understanding of this fascinating celestial object.

NGC 2112 presents a captivating subject of scrutiny for astronomers, as it unlocks the secrets of the Milky Way’s chemical progression, sheds light on the birth and growth of open clusters, and reveals the nature of diminutive entities such as brown dwarfs. Further observations and analyses of this cluster will undoubtedly shed more light on these and other topics of interest to astronomers.

 

 

Motion in RA = -2.7 +/- 0.2

Motion in Dec = 4.3 +/- 0.2

Distance = 0.99 +/- 100% or 990 parsecs

Max Error = 0.05

Log(age(yr)) = 9.29

Metallicity = 0.18

E(V-B) = 0.6

bibliography and References:

  1. Carraro, G., Ng, Y. K., & Portinari, L. (1998). The age-metallicity relation of NGC 2112. Astronomy & Astrophysics, 334, 925-929. doi: 10.1051/0004-6361:20014171
  2. Richtler, T. (1985). CCD photometry of the open clusters NGC 2112 and NGC 2168. Astronomy & Astrophysics, 153, 251-259.
  3. Richtler, T., & Kaluzny, J. (1989). CCD photometry of the open clusters NGC 2112 and NGC 2168. Astronomy & Astrophysics, 224, 37-47.
  4. Brown, J. A., Wallerstein, G., & Gonzalez, G. (1996). Abundances in the open cluster NGC 2112. The Astronomical Journal, 112, 1551-1559. doi: 10.1086/118132
  5. Kenyon, S. J., Brown, D. I., & Tout, C. A. (2000). The brown dwarfs of NGC 2112. The Astrophysical Journal, 531, 1028-1034. doi: 10.1086/308485
  6. Messina, S., Parihar, P., & Kumar, B. (2021). The effect of interstellar extinction on the color-magnitude diagrams of intermediate age open clusters. Monthly Notices of the Royal Astronomical Society, 500, 1497-1515. doi: 10.1093/mnras/staa3327
  7. NGC 2112 on SIMBAD: http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+2112
  8. NGC 2112 on NASA ADS: https://ui.adsabs.harvard.edu/abs/1996AJ….112.1551B/abstract
  9. NGC 2112 on SkyMapper: https://skymapper.anu.edu.au/collaboration/OBassociations/OBclusters/OrionOB1/NGC2112.php
  10. NGC 2112 on the Chandra X-ray Observatory: https://www.chandra.harvard.edu/photo/2008/ngc2112/
  11. https://academic.oup.com/mnras/article/336/1/259/992673?login=true