Photometric Determination of the Mass Accretion Rates of Pre-Main-Sequence Stars. Iv. Recent Star Formation in NGC 602

Marchi, Guido De; Beccari, G.; Panagia, N.

doi:10.1088/0004-637x/775/1/68

Cited by 37 publications

(45 citation statements)

References 77 publications

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“…11). We also plotted the age-mass accretion relation derived by De Marchi et al (2013) for the two clusters NGC 602 and NGC 346 represented by the long-dashed and short-dashed line, respectively. The slopes and mass accretion rates are similar to the ones of Wd2.…”

Section: Mass Accretion Rate As a Function Of Stellar Agementioning

confidence: 99%

A High-Resolution Multiband Survey of Westerlund 2 With the Hubble Space Telescope. Ii. Mass Accretion in the Pre-Main-Sequence Population

Zeidler

Grebel

Nota

et al. 2016

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We present a detailed analysis of the pre-main-sequence (PMS) population of the young star cluster Westerlund 2 (Wd2), the central ionizing cluster of the H II region RCW 49, using data from a high resolution multi-band survey with the Hubble Space Telescope. The data were acquired with the Advanced Camera for Surveys in the F 555W , F 814W , and F 658N filters and with the Wide Field Camera 3 in the F 125W , F 160W , and F 128N filters. We find a mean age of the region of 1.04 ± 0.72 Myr. The combination of dereddened F 555W and F 814W photometry in combination with F 658N photometry allows us to study and identify stars with Hα excess emission. With a careful selection of 240 bona-fide PMS Hα excess emitters we were able to determine their Hα luminosity, which has a mean value L(Hα) = 1.67 · 10 −31 erg s −1 . Using the PARSEC 1.2S isochrones to obtain the stellar parameters of the PMS stars we determined a mean mass accretion rateṀ acc = 4.43 · 10 −8 M ⊙ yr −1 per star. A careful analysis of the spatial dependence of the mass-accretion rate suggests that this rate is ∼ 25% lower in center of the two density peaks of Wd2 in close proximity to the luminous OB stars, compared to the Wd2 average. This rate is higher with increasing distance from the OB stars, indicating that the PMS accretion disks are being rapidly destroyed by the farultra-violet radiation emitted by the OB population.

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Section: Mass Accretion Rate As a Function Of Stellar Agementioning

confidence: 99%

A High-Resolution Multiband Survey of Westerlund 2 With the Hubble Space Telescope. Ii. Mass Accretion in the Pre-Main-Sequence Population

Zeidler

Grebel

Nota

et al. 2016

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“…Since the mass accretion rateṀ acc scales approximately linearly with the mass of the objects (e.g. De Marchi et al 2011aMarchi et al , 2013aBarentsen et al 2011;Spezzi et al 2012), the large difference in the sampled masses in the two datasets is a plausible explanation for the difference in the observed distribution ofṀ acc .…”

Section: Mass Accretion Ratesmentioning

confidence: 99%

“…5 these authors show an excellent correlation between the photometric and spectroscopic measures of EW(Hα) for emission stronger than 10 Å. The DM10 method was recently applied to the study of PMS objects in a number of star-burst clusters, namely NGC 3603 in the Galaxy (Beccari et al 2010), NGC 346 and NGC 602 in the Small Magellanic Clouds (see De Marchi et al 2011a, 2013a, 30 Doradus and three active star forming regions in the Large Magellanic Cloud (see De Marchi et al 2011b;Spezzi et al 2012). (Hur et al 2012, hereafter H12), whose properties have been thoroughly addressed in the literature.…”

Section: Introductionmentioning

confidence: 99%

Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

Beccari¹,

Marchi²,

Panagia³

et al. 2015

A&A

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We present a study of the mass accretion rates of pre-main sequence (PMS) stars in the cluster Trumpler 14 (Tr 14) in the Carina Nebula. Using optical multiband photometry we were able to identify 356 PMS stars showing Hα excess emission with equivalent width EW(Hα) > 20 Å. We interpret this observational feature as an indication that these objects are still actively accreting gas from their circumstellar medium. From a comparison of the HR diagram with PMS evolutionary models we derive ages and masses of the PMS stars. We find that most of the PMS objects are younger than 10 Myr with a median age of ∼3 Myr. Surprisingly, we also find that ∼20% of the mass accreting objects are older than 10 Myr. For each PMS star in Trumpler 14 we determine the mass accretion rate (Ṁ acc ) and discuss its dependence on mass and age. We finally combine the optical photometry with near-IR observations to build the spectral energy distribution (SED) for each PMS star in Tr 14. The analysis of the SEDs suggests the presence of transitional discs in which a large amount of gas is still present and sustains accretion onto the PMS object at ages older than 10 Myr. Our results, discussed in light of recent recent discoveries with Herschel of transitional discs containing a massive gas component around the relatively old PMS stars TW Hydrae, 49 Ceti, and HD 95086, support a new scenario n which old and evolved debris discs still host a significant amount of gas.

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“…Two generations of pre-main sequence (PMS) stars, one ∼1 Myr and one ∼10 Myr old, were found towards NGC 346 (De Marchi et al 2011b). De Marchi et al (2013) found a bimodal age distribution in NGC 602, with stars younger than 5 Myr and stars older A&A 573, A95 (2015) than 30 Myr. A younger (∼4 Myr) and an older (>12 Myr) PMS star population were also found in 30 Doradus, although with different spatial distributions (De Marchi et al 2011a).…”

Section: Introductionmentioning

confidence: 99%

Young open clusters in the Galactic star forming region NGC 6357

Massi

Giannetti

Carlo

et al. 2014

A&A

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Context. NGC 6357 is an active star forming region with very young massive open clusters. These clusters contain some of the most massive stars in the Galaxy and strongly interact with nearby giant molecular clouds. Aims. We study the young stellar populations of the region and of the open cluster Pismis 24, focusing on their relationship with the nearby giant molecular clouds. We seek evidence of triggered star formation "propagating" from the clusters. Methods. We used new deep JHK s photometry, along with unpublished deep Spitzer/IRAC mid-infrared photometry, complemented with optical HST/WFPC2 high spatial resolution photometry and X-ray Chandra observations, to constrain age, initial mass function, and star formation modes in progress. We carefully examine and discuss all sources of bias (saturation, confusion, different sensitivities, extinction). Results. NGC 6357 hosts three large young stellar clusters, of which Pismis 24 is the most prominent. We found that Pismis 24 is a very young (∼1-3 Myr) open cluster with a Salpeter-like initial mass function and a few thousand members. A comparison between optical and infrared photometry indicates that the fraction of members with a near-infrared excess (i.e., with a circumstellar disk) is in the range 0.3-0.6, consistent with its photometrically derived age. We also find that Pismis 24 is likely subdivided into a few different subclusters, one of which contains almost all the massive members. There are indications of current star formation triggered by these massive stars, but clear age trends could not be derived (although the fraction of stars with a near-infrared excess does increase towards the Hii region associated with the cluster). The gas out of which Pismis 24 formed must have been distributed in dense clumps within a cloud of less dense gas ∼1 pc in radius. Conclusions. Our findings provide some new insight into how young stellar populations and massive stars emerge, and evolve in the first few Myr after birth, from a giant molecular cloud complex.

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Photometric Determination of the Mass Accretion Rates of Pre-Main-Sequence Stars. Iv. Recent Star Formation in NGC 602

Cited by 37 publications

References 77 publications

A High-Resolution Multiband Survey of Westerlund 2 With the Hubble Space Telescope. Ii. Mass Accretion in the Pre-Main-Sequence Population

A High-Resolution Multiband Survey of Westerlund 2 With the Hubble Space Telescope. Ii. Mass Accretion in the Pre-Main-Sequence Population

Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

Young open clusters in the Galactic star forming region NGC 6357

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