The embedded star clusters in the nebulae vdB-RN 92 and Gy 3–7 in Canis Majoris R1

Soares, Jules Batista; Bica, E.

doi:10.1051/0004-6361:20030485

Cited by 15 publications

(6 citation statements)

References 17 publications

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“…Five resolved CMaX sources belong to these clusters, for which we have obtained similar ages. For the older cluster VdB-RN92 (5-7 Myr, Soares & Bica 2003) we have identified four other CMaX sources, but only one of them (CMaX-68) has compatible age, while the others seem to be massive stars for which the age determination is uncertain. Figure 10 presents the results, in the form of two panels, showing the broad distributions of ages and masses for all the CMaX sources in Field 1 and Field 2 respectively.…”

Section: Stellar Masses and Agesmentioning

confidence: 85%

Star formation history of Canis Major R1

Gregorio-Hetem¹,

Montmerle

Rodrigues

et al. 2009

A&A

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Aims. The CMa R1 star-forming region contains several compact clusters as well as many young early-B stars. It is associated with a well-known bright rimmed nebula, the nature of which is unclear (fossil HII region or supernova remnant). To help elucidate the nature of the nebula, our goal was to reconstruct the star-formation history of the CMa R1 region, including the previously unknown older, fainter low-mass stellar population, using X-rays. Methods. We analyzed images obtained with the ROSAT satellite, covering ∼5 sq. deg. Complementary VRI photometry was performed with the Gemini South telescope. Colour-magnitude and colour-colour diagrams were used in conjunction with pre-main sequence evolutionary tracks to derive the masses and ages of the X-ray sources.Results. The ROSAT images show two distinct clusters. One is associated with the known optical clusters near Z CMa, to which ∼40 members are added. The other, which we name the "GU CMa" cluster, is new, and contains ∼60 members. The ROSAT sources are young stars with masses down to M ∼ 0.5 M , and ages up to 10 Myr. The mass functions of the two clusters are similar, but the GU CMa cluster is older than the cluster around Z CMa by at least a few Myr. Also, the GU CMa cluster is away from any molecular cloud, implying that star formation must have ceased; on the contrary (as already known), star formation is very active in the Z CMa region.

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Section: Stellar Masses and Agesmentioning

confidence: 85%

Star formation history of Canis Major R1

Gregorio-Hetem¹,

Montmerle

Rodrigues

et al. 2009

A&A

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“…Undoubtedly, vdB 92 is part of a star-forming complex that deserves further analyses. With an approach that differs in various aspects from the present one, Soares & Bica (2003) studied the brighter sequences of vdB 92, deriving an age of 5-7 Myr, a mean visible absorption A v = 4.4, and d ≈ 1.5 kpc.…”

Section: Previous Data On Cr 197 and Vdb 92mentioning

confidence: 99%

The fate of the pre-main sequence-rich clusters Collinder 197 and vdB 92: dissolution?

Bonatto

Bica

2010

A&A

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Context. Since most of the star clusters do not survive the embedded phase, their early dissolution appears to be a major source of field stars. However, catching a cluster in the act of dissolving is somewhat elusive. Aims. We investigate the nature and possible evolution of the young Galactic star clusters Collinder 197 (Cr 197) and vdB 92. Methods. Photometric and structural properties were derived with near-infrared photometry and field-star decontamination. Kinematical properties were inferred from proper motions of the main sequence (MS) and pre-MS (PMS) member stars.Results. The colour-magnitude diagrams (CMDs) are basically characterised by a poorly-populated MS and a dominant fraction ( > ∼ 75%) of PMS stars, and the combined MS and PMS CMD morphology in both clusters consistently constrains the age to within 5 ± 4 Myr, with a ∼10 Myr spread in the star formation process. The MS+PMS stellar masses are ≈660 +101−51 M (vdB 92). Both Cr 197 and vdB 92 appear to be abnormally large when compared to clusters within the same age range. They have irregular stellar radial density distributions (RDPs) with a marked excess in the innermost region, a feature that, at less than 10 Myr, is more likely related to the star formation and/or molecular cloud fragmentation than to age-dependent dynamical effects. The velocity dispersion of both clusters, derived from proper motions, is in the range ∼15−22 km s −1 . Conclusions. Both clusters appear to be in a super-virial state, with velocity dispersions higher than those expected of nearly-virialised clusters of similar mass and size. A possible interpretation is that Cr 197 and vdB 92 deviate critically from dynamical equilibrium, and may dissolve into the field. We also conclude that early cluster dissolution leaves detectable imprints on RDPs of clusters as massive as several 10 2 M . Cr 197 and vdB 92 may be the link between embedded clusters and young stellar associations.

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“…Later, Sugitani et al (1995) observed a small bright-rimmed core, BRC 27, along the L1657 cloud edge and found infrared (IR)-excess stars there, and subsequently Ogura et al (2002) found 32 Hα emission stars towards the same cloud core. Soares & Bica (2002, 2003 used the 2MASS catalogue to study four small clusterings of young stars, including BRC 27. Gregorio-Hetem et al (2009) and Fernandes et al (2015) used X-ray data from ROSAT to identify young stars across a ∼5 sq.…”

Section: Introductionmentioning

confidence: 99%

Hα emission-line stars in molecular clouds

Pettersson

Reipurth

2019

A&A

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A deep objective-prism survey for Hα emission stars towards the Canis Major star-forming clouds was performed. A total of 398 Hα emitters were detected, 353 of which are new detections. There is a strong concentration of these Hα emitters towards the molecular clouds surrounding the CMa OB1 association, and it is likely that these stars are young stellar objects recently born in the clouds. An additional population of Hα emitters is scattered all across the region, and probably includes unrelated foreground dMe stars and background Be stars. About 90% of the Hα emitters are detected by WISE, of which 75 % was detected with usable photometry. When plotted in a WISE colour-colour diagram it appears that the majority are Class II YSOs. Coordinates and finding charts are provided for all the new stars, and coordinates for all the detections. We searched the Gaia-DR2 catalogue and from 334 Hα emission stars with useful parallaxes, we selected a subset of 98 stars that have parallax errors of less than 20% and nominal distances in the interval 1050 to 1350 pc that surrounds a strong peak at 1185 pc in the distance distribution. Similarly, Gaia distances were obtained for 51 OB-stars located towards Canis Major and selected with the same parallax errors as the Hα stars. We find a median distance for the OB stars of 1182 pc, in excellent correspondence with the distance from the Hα stars. Two known runaway stars are confirmed as members of the association. Finally, two new Herbig-Haro objects are identified.

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The embedded star clusters in the nebulae vdB-RN 92 and Gy 3–7 in Canis Majoris R1

Cited by 15 publications

References 17 publications

Star formation history of Canis Major R1

Star formation history of Canis Major R1

The fate of the pre-main sequence-rich clusters Collinder 197 and vdB 92: dissolution?

Hα emission-line stars in molecular clouds

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