Near–infrared and ISOCAM observations of the Chamaeleon II dark cloud

Persi, P.; Marenzi, Anna; Gómez, Mercedes; Olofsson, G.

doi:10.1051/0004-6361:20021856

Cited by 50 publications

(138 citation statements)

References 21 publications

(19 reference statements)

Supporting

Mentioning

134

Contrasting

Order By: Relevance

“…The total sample is therefore not as homogeneous as our surveys in ρ Ophiuchi (Bontemps et al 2001), Chamaeleon (Persi et al 2000) and RCrA . Also, since Serpens is at a larger distance the overall sensitivity is lower, and source confusion is worse, especially in the very clustered active centre.…”

Section: Luminosity Distributionmentioning

confidence: 60%

“…These were surveys within the ISO central programme mapping selected parts of the major nearby star formation regions in the two broad band filters LW2 (5−8.5 µm) and LW3 (12−18 µm). Other results on young stellar populations based on these surveys comprise the Chamaeleon I, II and III regions Olofsson et al 1998;Persi et al 2000), the ρ Ophiuchi star formation region (Bontemps et al 2001), the R Corona Australis region , and the L1551 Taurus region (Gålfalk et al 2004), all observations performed basically in the same way. Data reduction methods were generally the same for all regions, using a combination of the CIA 2 (CAM Interactive Analysis) package and own dedicated software.…”

Section: Isocammentioning

confidence: 94%

See 1 more Smart Citation

The young stellar population in the Serpens Cloud Core: An ISOCAM survey

Kaas

Olofsson

Bontemps

et al. 2004

A&A

Self Cite

221

View full text Add to dashboard Cite

Abstract. We present results from an ISOCAM survey in the two broad band filters LW2 (5−8.5 µm) and LW3 (12−18 µm) of a 0.13 square degree coverage of the Serpens Main Cloud Core. A total of 392 sources were detected in the 6.7 µm band and 139 in the 14.3 µm band to a limiting sensitivity of ∼2 mJy. We identified 53 Young Stellar Objects (YSOs) with mid-IR excess from the single colour index [14.3/6.7], and 8 additional YSOs from the H − K/K − m 6.7 diagram. Only 32 of these 61 sources were previously known to be YSO candidates. Only about 50% of the mid-IR excess sources show excesses in the near-IR J − H/H − K diagram. In the 48 square arcmin field covering the central Cloud Core the Class I/Class II number ratio is 19/18, i.e. about 10 times larger than in other young embedded clusters such as ρ Ophiuchi or Chamaeleon. The mid-IR fluxes of the Class I and flat-spectrum sources are found to be on the average larger than those of Class II sources. Stellar luminosities are estimated for the Class II sample, and its luminosity function is compatible with a coeval population of about 2 Myr which follows a three segment power-law IMF. For this age about 20% of the Class IIs are found to be young brown dwarf candidates. The YSOs are in general strongly clustered, the Class I sources more than the Class II sources, and there is an indication of sub-clustering. The sub-clustering of the protostar candidates has a spatial scale of 0.12 pc. These sub-clusters are found along the NW−SE oriented ridge and in very good agreement with the location of dense cores traced by millimeter data. The smallest clustering scale for the Class II sources is about 0.25 pc, similar to what was found for ρ Ophiuchi. Our data show evidence that star formation in Serpens has proceeded in several phases, and that a "microburst" of star formation has taken place very recently, probably within the last 10 5 yrs.Key words. stars: formation -stars: pre-main-sequence -stars: luminosity function, mass functionstars: low-mass, brown dwarfs -ISM: individual objects: Serpens Cloud Core Send offprint requests to: A. A. Kaas, e-mail: akaas@not.iac.es Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the United Kingdom) and with participation of ISAS and NASA. Tables 2 and 3 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via

show abstract

Section: Luminosity Distributionmentioning

confidence: 60%

Section: Isocammentioning

confidence: 94%

The young stellar population in the Serpens Cloud Core: An ISOCAM survey

Kaas

Olofsson

Bontemps

et al. 2004

A&A

Self Cite

221

View full text Add to dashboard Cite

show abstract

“…Again, the relative proximity (d = 160pc, Whittet et al 1997) and high galactic latitude (b ∼ −16 • ) of the clouds result in little foreground obscuration and make them ideal for star formation study. The region has been well-surveyed at millimetre wavelengths (Mattila et al 1989;Henning et al 1993) and more recently in the near- (Kenyon & Gómez 2001) and mid-infrared (Persi et al 2000). A single field was observed in the Cha I cloud, with the 6 pfov, centred on 11 h 09 m 39. s 4, −76 • 35 2 .…”

Section: Chamaeleon Imentioning

confidence: 89%

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

Alexander

Casali

André

et al. 2003

A&A

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…8) is a young very low mass object located in the Chamaeleon I dark cloud (d ∼ 140 ± 20 pc; Persi et al 2000). Its spectral type has been reported as being M6.25 and comparison with models give it a mass of 80 M JUP , a radius of 0.64 R and luminosity L bol = 0.023 to 0.028 (Muzerolle et al 2005;Luhman 2007).…”

Section: Targetmentioning

confidence: 99%

Accretion-ejection connection in the young brown dwarf candidate ISO-ChaI 217

Whelan

Alcalá

Bacciotti

et al. 2014

A&A

View full text Add to dashboard Cite

As the number of observed brown dwarf outflows is growing it is important to investigate how these outflows compare to the wellstudied jets from young stellar objects. A key point of comparison is the relationship between outflow and accretion activity and in particular the ratio between the mass outflow and accretion rates (Ṁ out /Ṁ acc ). The brown dwarf candidate ISO-ChaI 217 was discovered by our group, as part of a spectro-astrometric study of brown dwarfs, to be driving an asymmetric outflow with the blueshifted lobe having a position angle of ∼20 • . The aim here is to further investigate the properties of ISO-ChaI 217, the morphology and kinematics of its outflow, and to better constrainṀ out /Ṁ acc . The outflow is spatially resolved in the [S ] λλ6716, 6731 lines and is detected out to ∼1. 6 in the blue-shifted lobe and 1 in the red-shifted lobe. The asymmetry between the two lobes is confirmed although the velocity asymmetry is less pronounced with respect to our previous study. Using thirteen different accretion tracers we measure log (Ṁ acc ) [M /yr] = −10.6 ± 0.4. As it was not possible to measure the effect of extinction on the ISO-ChaI 217 outflowṀ out was derived for a range of values of A v , up to a value of A v = 2.5 mag estimated for the source extinction. The logarithm of the mass outflow (Ṁ out ) was estimated in the range −11.7 to −11.1 for both jets combined. ThusṀ out /Ṁ acc [M /yr] lies below the maximum value predicted by magneto-centrifugal jet launching models. Finally, both model fitting of the Balmer decrements and spectro-astrometric analysis of the Hα line show that the bulk of the H I emission comes from the accretion flow.

show abstract

Near–infrared and ISOCAM observations of the Chamaeleon II dark cloud

Cited by 50 publications

References 21 publications

The young stellar population in the Serpens Cloud Core: An ISOCAM survey

The young stellar population in the Serpens Cloud Core: An ISOCAM survey

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

Accretion-ejection connection in the young brown dwarf candidate ISO-ChaI 217

Contact Info

Product

Resources

About