Star Formation in Molecular Clouds: Observation and Theory

Shu, Frank H.; Adams, Fred C.; Lizano, Susana

doi:10.1146/annurev.aa.25.090187.000323

Cited by 2,251 publications

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“…Although there is a generally accepted theory of how a star forms through the collapse of a molecular cloud core and contracts to the main sequence (e.g., Shu et al 1987), two major breakthroughs in the mid-90s have added a new complexity to the star formation field: the discovery of exoplanets (Mayor & Queloz 1995) and brown dwarfs Rebolo et al 1995;Nakajima et al 1995). Brown dwarfs are a key element in understanding the origin of stellar masses and their distribution, the initial mass function (IMF), and in identifying the plethora of hospitable hosts where planetary systems can form.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopy of new brown dwarf members ofρ Ophiuchi and an updated initial mass function

Oliveira¹,

Moraux²,

Bouvier³

et al. 2012

A&A

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Aims. To investigate the universality hypothesis of the initial mass function in the substellar regime, the population of the ρ Ophiuchi molecular cloud is analysed by including a new sample of low-mass spectroscopically confirmed members. To that end, we have conducted a large spectroscopic follow-up of young substellar candidates uncovered in our previous photometric survey. Methods. The spectral types and extinction were derived for a newly found population of substellar objects, and its masses estimated by comparison to evolutionary models. A thoroughly literature search was conducted to provide an up-to-date census of the cluster, which was then used to derive the luminosity and mass functions, as well as the ratio of brown dwarfs to stars in the cluster. These results were then compared to other young clusters. Results. It is shown that the study of the substellar population of the ρ Ophiuchi molecular cloud is hampered only by the high extinction in the cluster ruling out an apparent paucity of brown dwarfs. The discovery of 16 new members of ρ Ophiuchi, 13 of them in the substellar regime, reveals the low-mass end of its population and shows the success of our photometric candidate selection with the WIRCam survey. The study of the brown dwarf population of the cluster reveals a high disk fraction of 76 +5 −8 %. Conclusions. Taking the characteristic peak mass of the derived mass function and the ratio of brown dwarfs to stars into account, we conclude that the mass function of ρ Ophiuchi is similar to other nearby young clusters.

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Section: Introductionmentioning

confidence: 99%

Spectroscopy of new brown dwarf members ofρ Ophiuchi and an updated initial mass function

Oliveira¹,

Moraux²,

Bouvier³

et al. 2012

A&A

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“…One of the simplest models for the morphology of starless cores is the singular isothermal sphere (SIS -Shu 1977;Shu et al 1987), which treats cores as isothermal objects with an inverse square radial density profile:…”

Section: Morphologymentioning

confidence: 99%

Submillimetre Studies of Prestellar and Starless Cores in the Ophiuchus, Taurus and Cepheus Molecular Clouds

Pattle¹

2017

Springer Theses

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“…This free-fall time has probably to be considered as a strict lower limit to the lifetime of the cloud, since additional pressure support from fluid turbulence and magnetic field may inhibit the collapse [10]. The effectiveness of the cosmic ray penetration into the cloud depends on the interplay of several physical processes: (i) diffusion in the cloud magnetic field, (ii) advection due to turbulent bulk motion inside the cloud, (iii) energy losses in the dense cloud medium.…”

Section: Charcateristic Time Scales Of the Problemmentioning

confidence: 99%

Gamma rays from molecular clouds

Gabici¹,

Aharonian²,

Blasi³

2007

The Multi-Messenger Approach to High-Energy Gamma-Ray Sources

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It is believed that the observed diffuse gamma ray emission from the galactic plane is the result of interactions between cosmic rays and the interstellar gas. Such emission can be amplified if cosmic rays penetrate into dense molecular clouds. The propagation of cosmic rays inside a molecular cloud has been studied assuming an arbitrary energy and space dependent diffusion coefficient. If the diffusion coefficient inside the cloud is significantly smaller compared to the average one derived for the galactic disk, the observed gamma ray spectrum appears harder than the cosmic ray spectrum, mainly due to the slower penetration of the low energy particles towards the core of the cloud. This may produce a great variety of gamma ray spectra.PACS First · Second · More

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Star Formation in Molecular Clouds: Observation and Theory

Cited by 2,251 publications

References 0 publications

Spectroscopy of new brown dwarf members ofρ Ophiuchi and an updated initial mass function

Spectroscopy of new brown dwarf members ofρ Ophiuchi and an updated initial mass function

Submillimetre Studies of Prestellar and Starless Cores in the Ophiuchus, Taurus and Cepheus Molecular Clouds

Gamma rays from molecular clouds

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