The location of the hot molecular core in Orion

Zuckerman, B.; Morris, M.; Palmer, Patrick

doi:10.1086/183670

Cited by 4 publications

(2 citation statements)

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“…The ONC has a size of ∼3 pc (Hillenbrand & Hartmann, 1998) and an age of about 10 6 yr (Hillenbrand, 1997). The OHC, located within the Orion KL nebula (Zuckerman et al, 1981;Shuping et al, 2004) is a very compact (size of ∼ 0.03 pc), hot (T>200K), and dense molecular condensation (mean density of n[H 2 ]=5×10 7 cm −3 , Morris et al, 1980), with a total luminosity of few 10 5 L ⊙ (de Vicente et al, 2002). The OHC is the prototype object for studying the formation of massive stars.…”

Section: Introductionmentioning

confidence: 99%

The role of low-mass star clusters in massive star formation. The Orion case

Rivilla

Martı́n-Pintado

Jiménez-Serra

et al. 2013

A&A

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Context. Different theories have been proposed to explain the formation of massive stars: two are based on accretion processes (monolithic core accretion and competitive accretion), and another on coalescence of low-and intermediate-mass stars. To distinguish between these theories, it is crucial to establish the distribution, the extinction, and the density of young low-mass stars in massive star-forming regions. X-ray observations can penetrate the very obscured cradles of massive stars, directly sampling the distribution of the population of pre-main sequence (PMS) low-mass stars in these regions. Aims. Our aim is to analyze deep X-ray observations of the Orion massive star-forming region using the Chandra Orion Ultradeep Project (COUP) catalog, to reveal the distribution of the population and clustering of PMS low-mass stars, and to study their possible role in massive star formation. Methods. We studied the distribution of PMS low-mass stars with X-ray emission in Orion as a function of extinction with two different methods: a spatial gridding and a close-neigbors method with cells of ∼0.03 × 0.03 pc 2 , the typical size of protostellar cores. We derived density maps of the stellar population and calculated cluster stellar densities. Results. Consistent with previous studies, we found that PMS low-mass stars cluster toward the three massive star-forming regions: the Trapezium cluster (TC), the Orion hot core (OHC), and the OMC1-S region. We derived PMS low-mass stellar densities of 10 5 stars pc −3 in the TC and OMC1-S, and of 10 6 stars pc −3 in the OHC. The close association between the low-mass star clusters with massive star cradles supports the role of these clusters in the formation of massive stars. The X-ray observations show for the first time in the TC that low-mass stars with intermediate extinction are clustered toward the position of the most massive star θ 1 Ori C, which is surrounded by a ring of non-extincted PMS low-mass stars. This "envelope-core" structure is also supported by infrared and optical observations. Our analysis suggests that at least two basic ingredients are needed in massive star formation: the presence of dense gas and a cluster of low-mass stars. The scenario that better explains our findings assumes high fragmentation in the parental core, accretion at subcore scales that forms a low-mass stellar cluster, and subsequent competitive accretion. Finally, although coalescence does not seem a common mechanism for building up massive stars, we show that a single stellar merger may have occurred in the evolution of the OHC cluster, favored by the presence of disks, binaries, and gas accretion.

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Section: Introductionmentioning

confidence: 99%

The role of low-mass star clusters in massive star formation. The Orion case

Rivilla

Martı́n-Pintado

Jiménez-Serra

et al. 2013

A&A

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“…Like most IR sources in the KL region, there has been some speculation on the nature of these objects and whether they are simply knots of dust in the complex nebulosity or embedded stars. For example, Zuckerman et al (1981) argued that IRc4 is selfluminous because they determined that it coincides with the peak of the hot core defined by high-lying ammonia lines, and Aitken et al (1981) suggested that IRc4 contains a luminosity source because of the shape of its deep silicate feature, which requires a range of dust temperatures. However, Wynn-Williams et al (1984), and most investigators since (e.g., Gezari et al 1998) have considered that IRc3 and IRc4 are externally heated knots of dust or are "holes" in the clumpy, dense shell surrounding a luminous cavity.…”

Section: Sources Irc3 Irc4 and Irc7mentioning

confidence: 99%

FIRST SCIENCE OBSERVATIONS WITH SOFIA/FORCAST: 6-37 μm IMAGING OF ORION BN/KL

Buizer

Morris

Becklin

et al. 2012

ApJ

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The BN/KL region of the Orion Nebula is the nearest region of high mass star formation in our galaxy. As such, it has been the subject of intense investigation at a variety of wavelengths, which have revealed it to be brightest in the infrared to sub-mm wavelength regime. Using the newly commissioned SOFIA airborne telescope and its 5-40 µm camera FORCAST, images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 µm images represent the highest resolution observations ( 4 ′′ ) ever obtained of this region at these wavelengths. These observations reveal that the BN object is not the dominant brightness source in the complex at wavelengths ≥31.5 µm, and that this distinction goes instead to the source IRc4. It was determined from these images and derived dust color temperature maps that IRc4 is also likely to be self-luminous. A new source of emission has also been identified at wavelengths ≥31.5 µm that coincides with the northeastern outflow lobe from the protostellar disk associated with radio source I.

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SOFIA – A Brief Overview of ISM Science Highlights to Date

Zinnecker

2015

EAS Publications Series

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The location of the hot molecular core in Orion

Cited by 4 publications

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The role of low-mass star clusters in massive star formation. The Orion case

The role of low-mass star clusters in massive star formation. The Orion case

FIRST SCIENCE OBSERVATIONS WITH SOFIA/FORCAST: 6-37 μm IMAGING OF ORION BN/KL

SOFIA – A Brief Overview of ISM Science Highlights to Date

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