The evolutionary status of the stellar population in the rho Ophiuchi cloud core

Strom, K. M.; Kepner, Jeremy; Strom, S. E.

doi:10.1086/175125

Cited by 73 publications

(80 citation statements)

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“…The ages of the stars are inferred to lie in the range 0.3−1 Myr (Wilking et al 1989;Greene & Meyer 1995;Luhman & Rieke 1999). Bontemps et al (2001) find, after correcting for an assumed binary fraction of 75 percent, a stellar mass-function for young stellar objects (YSOs) that is consistent with the slope of the canonical stellar IMF for low masses (0.055−0.55 M ) and agrees with earlier (Comeron et al 1993;Strom et al 1995;Motte et al 1998;Johnstone et al 2000) and later (Tachihara et al 2002;Stanke et al 2006) studies. A somewhat steeper mass-function than the canonical IMF is observed for higher stellar masses (α 2 = 1.7 in Eq.…”

Section: ρ Ophiuchussupporting

confidence: 83%

Inverse dynamical population synthesis

Marks

Kroupa

2012

A&A

240

302

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Binary populations in young star clusters show multiplicity fractions both lower and up to twice as high as those observed in the Galactic field. We follow the evolution of a population of binary stars in dense and loose star clusters starting with an invariant initial binary population and a formal multiplicity fraction of unity, and demonstrate that these models can explain the observed binary properties in Taurus, ρ Ophiuchus, Chamaeleon, Orion, IC 348, Upper Scorpius A, Praesepe, and the Pleiades. The model needs to consider solely different birth densities for these regions. The evolved theoretical orbital-parameter distributions are highly probable parent distributions for the observed ones. We constrain the birth conditions (stellar mass, M ecl , and half-mass radius, r h ) for the derived progenitors of the star clusters and the overall present-day binary fractions allowed by the present model. The results compare very well with properties of molecular cloud clumps on the verge of star formation. Combining these with previously and independently obtained constraints on the birth densities of globular clusters, we identify a weak stellar mass -half-mass radius correlation for cluster-forming cloud clumps, r h /pc ∝ (M ecl /M ) 0.13 ± 0.04 . The ability of the model to reproduce the binary properties in all the investigated young objects, covering present-day densities from 1−10 stars pc −3 (Taurus) to 2 × 10 4 stars pc −3 (Orion), suggests that environment-dependent dynamical evolution plays an important role in shaping the present-day properties of binary populations in star clusters, and that the initial binary properties may not vary dramatically between different environments.

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Section: ρ Ophiuchussupporting

confidence: 83%

Inverse dynamical population synthesis

Marks

Kroupa

2012

A&A

240

302

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“…Support for this work was provided in part by NASA through Chandra Award Number AR1-2005A and NASA Long-Term Space Astrophysics (NAG 5-8412). Barsony et al (1997), GSS is from Grasdalen, Strom, & Strom (1973, and [SKS95] is from Strom, Kepner, & Strom (1995). Barsony et al (1997), HBC is from Herbig & Bell (1988), and WSB is from .…”

Section: Discussionmentioning

confidence: 99%

“…Barsony et al (1997), HBC is from Herbig & Bell (1988), and WSB is from . Barsony et al (1997), Elias 2 is from Elias (1978), GSS is from Grasdalen et al (1973), [GY92] is from Greene & Young (1992), and [SKS95] is from Strom et al (1995). Barsony et al (1997), [GY92] is from Greene & Young (1992), GSS is from Grasdalen et al (1973), and [SKS95] is from Strom et al (1995).…”

Section: Discussionmentioning

confidence: 99%

Jets and Herbig-Haro Objects in the Ophiuchi Embedded Cluster

et al. 2003

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We present results from a near-infrared 2.12 lm survey covering a large portion of the Ophiuchi cloud (three regions of $20 0 Â 20 0 each, on average) in an effort to improve the detection of embedded molecular hydrogen emission objects in the cloud. We complement these observations with deep optical [S ii] images of six areas of 10 0 Â 10 0 each. We recovered all previously known optical jets/Herbig-Haro (HH) objects as well as H 2 outflows in the region and report the detection of four new HH objects and 13 near-infrared knots. We provide coordinates and describe the morphology of these knots, several of which are identified as belonging to the same flow on the basis of morphological and proximity arguments. We discuss likely exciting sources. A unique association of the driving star is not always possible, as several young stars lie in close proximity to these knots.

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“…Its relatively high galactic latitude (b = 17 • ) combined with its relative proximity (d = 160 pc, Whittet 1974) result in comparatively little foreground obscuration, making it an ideal region in which to study star formation. Initially identified by Grasdalen et al (1973), who identified 41 sources in a K-band map, it has since been studied extensively both in the infrared (Elias 1978;Greene & Young 1992;Strom et al 1995;Abergel et al 1996;Bontemps et al 2001) and at millimetre wavelengths (Loren et al 1990;André & Montmerle 1994). In particular, Loren et al (1990) showed that the cloud consists of a number of smaller sub-structures.…”

Section: ρ Ophiuchimentioning

confidence: 99%

ISOCAM-CVF spectroscopy of the circumstellar environment of young stellar objects

Alexander

Casali

André

et al. 2003

A&A

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Abstract. We present the results of a mid-infrared (5-16.5 µm) imaging spectroscopy survey of Young Stellar Objects (YSOs) and their surrounding environment in four low-mass star formation regions: RCrA, ρ Ophiuchi, Serpens and Chamaeleon I. This survey was performed using ISOCAM and its Circular Variable Filters (CVF) and observed 42 YSO candidates: we were able to obtain complete 5-16.5 µm spectra for 40 of these with a spectral resolving power of λ/∆λ 40. A number of spectral features were measured, most notably the 9.7 µm silicate feature, the bending modes of both water and CO 2 ices at 6.0 and 15.2 µm respectively and the well-known unidentified feature at 6.8 µm. The strength of the unidentified feature was observed to correlate very well with that of the water ice bending mode and far less strongly with the CO 2 ice bending mode. This suggests, in a manner consistent with previous observations, that the carrier of the unidentified feature is a strongly polar ice. Absorption profiles of the bending mode of CO 2 ice are observed to show a significant long wavelength wing, which suggests that a significant fraction of the CO 2 ice observed exists in a polar (H 2 O-rich) phase. The sources observed in RCrA, ρ Oph and Serpens show similar spectral characteristics, whilst the sources observed in Cha I are somewhat anomalous, predominantly showing silicate emission and little or no absorption due to volatile ices. However this is consistent with previous studies of this region of the Cha I cloud, which contains an unusual cluster of YSOs. From comparisons of the strengths of the water ice and silicate bands we detect an apparent under-abundance of water ice towards the sources in ρ Oph, relative to both RCrA and Serpens. This may be indicative of differences in chemical composition between the different clouds, or may be due to evaporation. Finally the CO 2 :H 2 O ice ratios observed towards the sources in ρ Oph show significantly greater scatter than in the other regions, possibly due to varying local conditions around the YSOs in ρ Oph.

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The evolutionary status of the stellar population in the rho Ophiuchi cloud core

Cited by 73 publications

References 0 publications

Inverse dynamical population synthesis

Inverse dynamical population synthesis

Jets and Herbig-Haro Objects in the Ophiuchi Embedded Cluster

ISOCAM-CVF spectroscopy of the circumstellar environment of young stellar objects

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