Pre-main-sequence isochrones – III. The Cluster Collaboration isochrone server

Bell, Cameron P. M.; Rees, Jon M.; Naylor, T.; Mayne, Nathan J.; Jeffries, R. D.; Mamajek, Eric E.; Rowe, J.N

doi:10.1093/mnras/stu1944

Cited by 43 publications

(56 citation statements)

References 94 publications

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“…Masses were then estimated given the position of the de-redden, and distance-corrected star inside the CMD in relation to a grid of PMS semi-empirical isochrones from Bell et al (2014), with PISA models (Tognelli et al 2011(Tognelli et al , 2012 for solar metallicity (Z =0.013), and ages in the range 0.1-30 Myr. The grid of semi-empirical isochrones was built by using the CMDfit software 7 , and the bolometric corrections applied were calculated by the software's authors by folding spectra with opacities from BT-Settl (Allard et al 2011) through the desired filter response and applying empirical corrections from Bell et al (2014). In our case, we chose the filter responses for SDSS filters (Doi et al 2010) with an AB zero point.…”

Section: Mass Estimationmentioning

confidence: 99%

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Near-infrared time-series photometry in the field of Cygnus OB2 association

Roquette

Bouvier

Alencar

et al. 2017

A&A

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Context. In the last decades, the early pre main sequence stellar rotational evolution picture has been constrained by studies targetting different regions at a variety of ages with respect to young star formation. Observational studies suggest a dependence of rotation with mass, and for some mass ranges a connection between rotation and the presence of a circumstellar disk. Not still fully explored, though, is the role of environmental conditions on the rotational regulation.Aims. We investigate the rotational properties of candidate members of the young massive association Cygnus OB2. By evaluating their rotational properties, we address questions regarding the effect of environment properties on PMS rotational evolution.Methods. We studied JHK-band variability in 5083 candidate members (24% of them are diskbearing stars). The selection of variable stars was done using Stetson variability index, and period search was performed using Lomb-Scargle periodogram for periods between 0.83-45 days. Period detections were verified by using False Alarme Probability levels, the Saunders statistics, string/rope length method, and visual verification of folded light curves.Results. We identified 1224 periodic variable stars (24% of the candidate member sample, 8% of the disk-bearing sample, and 28% of the non-disked sample). Monte Carlo simulations were performed in order to evaluate completeness and contamination of the periodic sample, out of which 894 measured periods were considered reliable. Our study was considered reasonably complete for periods between 2 and 30 days. Conclusions. The general scenario for the rotational evolution of young stars seen in other regions is confirmed by Cygnus OB2 period distributions, with disked stars rotating on average slower than non-disked stars. A mass-rotation dependence was also verified, but as in NGC 6530, very low mass stars (M ≤ 0.4M ) are rotating on average slower than higher mass stars (0.4 M < M ≤ 1.4M ). We observed an excess of slow rotators among the lower mass population. The disk and mass-rotation connection was also analysed by taking into account the incident UV radiation arising from O stars in the association. Results compatible with the disk-locking scenario were verified for stars with low UV incidence, but no statistical significant relation between rotation and disk presence was verified for stars with high UV incidence suggesting that massive stars can have an important role on regulating the rotation of nearby low mass stars.Key words. infrared: stars -stars: variables: T Tauri -stars: low-mass -stars: formation -stars: pre main sequence -stars: rotation Use \titlerunning to supply a shorter title and/or \authorrunning to supply a shorter list of authors.

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Section: Mass Estimationmentioning

confidence: 99%

“…We repeated the process for estimating masses described in Section 4.3.1 using 3 other models: Baraffe et al (1998), and Baraffe et al (2015) with Bell et al (2014) empirical corrections, and Siess et al (2000). The first two models result in masses very similar to the ones we adopted.…”

Section: Period Distributions In Different Mass Rangesmentioning

confidence: 99%

Near-infrared time-series photometry in the field of Cygnus OB2 association

Roquette

Bouvier

Alencar

et al. 2017

A&A

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“…The zero-age main sequence (ZAMS) of Marigo et al (2008) and PMS isochrones from the Pisa models (Bell et al 2014) are also shown. These PMS models are based on an interior model of Tognelli et al (2011Tognelli et al ( , 2012 with the Allard et al (2011), Brott & Hauschildt (2005, and Castelli & Kurucz (2010) bolometric corrections and additional empirical corrections as discussed in Bell et al (2014). The isochrones were corrected for a distance of 1.3 kpc and a visual extinction of 8.5 mag (see Sect.…”

Section: Age Of Rcw 41mentioning

confidence: 99%

“…Figure 15 displays three of them, namely models from Baraffe et al (2003Baraffe et al ( , 1998, and Tognelli et al (2011). Those two last theoretical models have been converted into magnitudes using the semi-empirical bolometric corrections by Bell et al (2014). All three models are displayed with two different ages: 1 Myr and 2.5 Myr.…”

Section: Imfmentioning

confidence: 99%

Deep near-infrared adaptive-optics observations of a young embedded cluster at the edge of the RCW 41 H II region

Neichel

Samal

Plana

et al. 2015

A&A

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Aims. We investigate the star formation activity in a young star forming cluster embedded at the edge of the RCW 41 H ii region. As a complementary goal, we aim to demonstrate the gain provided by wide-field adaptive optics (WFAO) instruments to study young clusters. Methods. We used deep, JHK s images from the newly commissioned Gemini-GeMS/GSAOI instrument, complemented with Spitzer IRAC observations, in order to study the photometric properties of the young stellar cluster. GeMS is a WFAO instrument that delivers almost diffraction-limited images over a field of ∼2 across. The exquisite angular resolution allows us to reach a limiting magnitude of J ∼ 22 for 98% completeness. The combination of the IRAC photometry with our JHK s catalog is used to build color−color diagrams, and select young stellar object (YSO) candidates. The JHK s photometry is also used in conjunction with pre-main sequence evolutionary models to infer masses and ages. The K-band luminosity function is derived, and then used to build the initial mass function (IMF) of the cluster. Results. We detect the presence of 80 YSO candidates. Those YSOs are used to infer the cluster age, which is found to be in the range 1 to 5 Myr. More precisely, we find that 1/3 of the YSOs are in a range between 3 to 5 Myr, while 2/3 of the YSO are ≤3 Myr. When looking at the spatial distribution of these two populations, we find evidence of a potential age gradient across the field that suggests sequential star formation. We construct the IMF and show that we can sample the mass distribution well into the brown dwarf regime (down to ∼0.01 M ). The logarithmic mass function rises to peak at ∼0.3 M , before turning over and declining into the brown dwarf regime. The total cluster mass derived is estimated to be 78 ± 18 M , while the ratio derived of brown dwarfs to star is 18 ± 5%. When comparing it with other young clusters, we find that the IMF shape of the young cluster embedded within RCW 41 is consistent with those of Trapezium, IC 348, or Chamaeleon I, except for the IMF peak, which happens to be at higher mass. This characteristic is also seen in clusters like NGC 6611 or even Taurus. These results suggest that the medium-to-low mass end of the IMF possibly depends on environment.

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“…Stauffer et al (2003) have studied this wavelength-dependent spectral type effect among the zero-age main sequence K dwarfs in the Pleiades (∼135 Myr; Bell et al 2014). The Stauffer et al (2003) study found that the spectral type of Pleiades K-type stars were systematically ∼1 subtype later in the red optical spectra than the blue optical spectra.…”

Section: Young Stellar Colors and Spectral Typesmentioning

confidence: 99%

Anomalous Spectral Types and Intrinsic Colors of Young Stars

Pecaut

2015

Proc. IAU

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Abstract. We highlight differences in spectral types and intrinsic colors observed in pre-main sequence (pre-MS) stars. Spectral types of pre-MS stars are wavelength-dependent, with nearinfrared spectra being 3-5 spectral sub-classes later than the spectral types determined from optical spectra. In addition, the intrinsic colors of young stars differ from that of main-sequence stars at a given spectral type. We caution observers to adopt optical spectral types over nearinfrared types, since Hertzsprung-Russell (H-R) diagram positions derived from optical spectral types provide consistency between dynamical masses and theoretical evolutionary tracks. We also urge observers to deredden pre-MS stars with tabulations of intrinsic colors specifically constructed for young stars, since their unreddened colors differ from that of main sequence dwarfs. Otherwise, V -band extinctions as much as ∼0.6 mag erroneously higher than the true extinction may result, which would introduce systematic errors in the H-R diagram positions and thus bias the inferred ages.

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Pre-main-sequence isochrones – III. The Cluster Collaboration isochrone server

Cited by 43 publications

References 94 publications

Near-infrared time-series photometry in the field of Cygnus OB2 association

Near-infrared time-series photometry in the field of Cygnus OB2 association

Deep near-infrared adaptive-optics observations of a young embedded cluster at the edge of the RCW 41 H II region

Anomalous Spectral Types and Intrinsic Colors of Young Stars

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