Infrared images of the young cluster NGC 2264

Lada, Charles J.; Young, Erick T.; Greene, Thomas P.

doi:10.1086/172605

Cited by 75 publications

(85 citation statements)

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“…We find that our estimate of the power-law slopes is in remarkable agreement with that of Megeath et al (1996), in spite of the larger survey area that includes objects such as compact H ii, ultracompact H ii, and diffuse H ii regions. Our results therefore confirm that the KLF of the W3 Main region shows a power-law slope that is lower than those generally reported for young embedded clusters ( $ 0:4; e.g., Lada et al , 1993Lada & Lada 2003). Thus, this low value of the slope is indeed an intrinsic property of the stellar population in this region.…”

Section: The K S -Band Luminosity Functionsupporting

confidence: 90%

Deep Near‐Infrared Observations of the W3 Main Star‐forming Region

Ojha

Tamura

Nakajima

et al. 2004

ApJ

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We present a deep JHK s -band imaging survey of the W3 Main star-forming region, using the near-infrared camera SIRIUS mounted on the University of Hawaii 2.2 m telescope. The near-infrared survey covers an area of $24 arcmin 2 with 10 limiting magnitudes of $19.0, 18.1, and 17.3 in the J, H, and K s bands, respectively. We construct JHK color-color and J versus JÀH and K versus HÀK color-magnitude diagrams to identify young stellar objects and estimate their masses. Based on these color-color and color-magnitude diagrams, a rich population of young stellar objects is identified that is associated with the W3 Main region. A large number of previously unreported red sources (HÀK > 2) have also been detected around W3 Main. We argue that these red stars are most probably pre-main-sequence stars with intrinsic color excesses. We find that the slope of the K s -band luminosity function (KLF) of W3 Main is lower than the typical values reported for young embedded clusters. The derived slope of the KLF is the same as that found in 1996 by Megeath and coworkers, from which analysis indicated that the W3 Main region has an age in the range of 0.3-1 Myr. Based on the comparison between models of pre-main-sequence stars and the observed color-magnitude diagram, we find that the stellar population in W3 Main is primarily composed of low-mass pre-main-sequence stars. We also report the detection of isolated young stars with large infrared excesses that are most probably in their earliest evolutionary phases.

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Section: The K S -Band Luminosity Functionsupporting

confidence: 90%

Deep Near‐Infrared Observations of the W3 Main Star‐forming Region

Ojha

Tamura

Nakajima

et al. 2004

ApJ

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“…The size of the stellar population of the NGC 2264 cluster (within this area) is therefore estimated to be 1436 ± 242. Lada et al (1993) used this same method to statistically determine the number of sources of NGC 2264: they found 360 ± 130 sources (K s < 13.5 mag), albeit for a smaller area: 540 arcmin 2 .…”

Section: Star Formation Efficiencymentioning

confidence: 99%

“…The majority of the IC 348 sources classified as classical T Tauri stars (CTTS) (i.e., accreting according to the equivalent width of their Hα emission) were found to possess thick disks, while the majority of the weak-line T Tauri stars (WTTS) (i.e., non-accreting according to the equivalent width of their Hα emission) were found to be disk-less, leading the authors to conclude that the gaseous and dust components of disks evolve on similar timescales. NGC 2264 is a young hierarchical cluster (Piche 1993;Lada et al 1993;Lada & Lada 2003) located in the Monoceros OB1 association, that has been extensively studied since Walker (1956)'s seminal work identifiying its pre-main sequence A&A 540, A83 (2012) population (PMS). The most recent distance measurement to the cluster places it at 913 ± 110 pc (Baxter et al 2009) (the value used in this paper); previous estimates of the cluster distance had varied between 700 pc and 800 pc.…”

Section: Introductionmentioning

confidence: 99%

Spitzerobservations of NGC 2264: the nature of the disk population

Teixeira

Lada

Marengo

et al. 2012

A&A

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Aims. NGC 2264 is a young cluster with a rich circumstellar disk population which makes it an ideal target for studying the evolution of stellar clusters. Our goal is to study the star formation history of NGC 2264 and to analyse the primordial disk evolution of its members. Methods. The study presented is based on data obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS) on board the Spitzer Space Telescope, combined with deep near-infrared (NIR) ground-based FLAMINGOS imaging and previously published optical data. Results. We build NIR dust extinction maps of the molecular cloud associated with the cluster, and determine it to have a mass of 2.1 × 10 3 M above an A V of 7 mag. Using a differential K s -band luminosity function (KLF) of the cluster, we estimate the size of the population of NGC 2264, within the area observed by FLAMINGOS, to be 1436 ± 242 members. The star formation efficiency is ≥∼25%. We identify the disk population and divide it into 3 groups based on their spectral energy distribution slopes from 3.6 μm to 8 μm and on the 24 μm excess emission: (i) optically thick inner disks, (ii) anaemic inner disks, and (iii) disks with inner holes, or transition disks. We analyse the spatial distribution of these sources and find that sources with thick disks segregate into subclusterings, whereas sources with anaemic disks do not. Furthermore, sources with anaemic disks are found to be unembedded (i.e., with A V < 3 mag), whereas the clustered sources with thick disks are still embedded within the parental cloud. Conclusions. NGC 2264 has undergone more than one star-forming event, where the anaemic and extincted thick disk population appear to have formed in separate episodes: the sources with anaemic disks are more evolved and have had time to disperse and populate a halo of the cluster. We also find tentative evidence of triggered star-formation in the Fox Fur Nebula. In terms of disk evolution, our findings support the emerging disk evolution paradigm of two distinct evolutionary paths for primordial optically thick disks: a homologous one where the disk emission decreases uniformly at NIR and mid-infrared (MIR) wavelengths, and a radially differential one where the emission from the inner region of the disk decreases more rapidly than from the outer region (forming transition disks).

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“…(For convenience, we will refer in this paper to the binary as AR 6.) The NGC 2264 complex, of which the Cone Nebula is a part, is an extremely active region of star formation (e.g., Lada et al 1993; and is located at a distance of about 800 pc (Walker 1956). The goal of this investigation is to estimate the approximate evolutionary stage of the AR 6 FUor candidates.…”

Section: Introductionmentioning

confidence: 99%

The Local Environment of the Fu-Orionis-Like Objects Ar 6a and 6b

Moriarty‐Schieven

Aspin

Davis

2008

The Astronomical Journal

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We present new 12 CO J = 3-2 and HCN J = 3-2 molecular line maps of the region surrounding the young star AR 6 using the 15 m James Clerk Maxwell Telescope (JCMT). AR 6 was previously found to be a double source with both components exhibiting several characteristics of FU Orionis (FUor) eruptive variable stars. The aims of this investigation were to determine if the AR 6 sources are associated with molecular outflows and if a significant reservoir of natal molecular gas and dust exists around the stars. These observations form a part of a large-scale study of the outflow and circumstellar environment characteristics of FUors and FUor-like objects to place constrains on the age and evolutionary state of sources exhibiting FUor-like tendencies. Our data indicate that AR 6, like FUor itself, does not possess a CO outflow and likewise, does not show evidence for large amounts of molecular gas in its circumstellar environment. In fact, AR 6 seems to lie in a local minimum of HCN emission. This is also found in 850 μm dust emission seen in JCMT archival data. We conclude that from the near-infrared to the sub-millimeter, AR 6 is similar to FUor in several respects. We interpret the lack of significant dust and molecular gas in the circumstellar environment of AR 6, together with the large near-infrared (NIR) thermal excess, as evidence that the sources have exhausted their natal envelopes, that they have at least small hot circumstellar disks, and that they are more evolved than Class I protostars. This, in itself, suggests that, since FUor eruptions have also been observed in stars with large dust mass envelopes (e.g., V346 Nor) and with CO outflows (e.g., L1551 IRS5), FUor events probably occur at many different stages in the early, formative phase of a star's life, and lends support to the idea that FUor outbursts are repetitive like their shorter-lived relatives occurring in EXor eruptive variables. Finally, we study the stellar environment around AR 6 using Two Micron All Sky Survey, Spitzer Infrared Array Camera, and Chandra ACIS images and show that, being part of the "Spokes" young stellar cluster, AR 6 is unlike many FUors which are typically located in more sparsely populated regions.

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Infrared images of the young cluster NGC 2264

Cited by 75 publications

References 0 publications

Deep Near‐Infrared Observations of the W3 Main Star‐forming Region

Deep Near‐Infrared Observations of the W3 Main Star‐forming Region

Spitzerobservations of NGC 2264: the nature of the disk population

The Local Environment of the Fu-Orionis-Like Objects Ar 6a and 6b

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