Multiwavelength study of a young open cluster NGC 7419

Joshi, Himali; Kumar, Brijesh; Singh, K. P.; Sagar, Ram; Sharma, Saurabh; Pandey, J. C.

doi:10.1111/j.1365-2966.2008.13936.x

Cited by 17 publications

(30 citation statements)

References 68 publications

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“…In this respect, it is worth considering the properties of the open cluster NGC 7419, which contains five RSGs and, though moderately extinguished, is visible in the optical. The 2MASS colour−magnitude diagram for NGC 7419 does not show a well defined sequence, in spite of the fact that the field contamination is very small at the magnitudes of the brightest blue members (Joshi et al 2008). This is due to differential reddening and the presence of a significant fraction of Be stars amongst the brightest members, which show important colour excesses.…”

Section: The Cluster Against the Backgroundmentioning

confidence: 93%

Another cluster of red supergiants close to RSGC1

Negueruela¹,

González-Fernández²,

Marco³

et al. 2010

A&A

106

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Context. Recent studies have revealed massive star clusters in a region of the Milky Way close to the tip of the Long Bar. These clusters are heavily obscured and are characterised by a population of red supergiants. Aims. We analyse a previously unreported concentration of bright red stars ∼16 away from the cluster RSGC1 Methods. We utilised near IR photometry to identify candidate red supergiants and then K-band spectroscopy of a sample to characterise their properties. Results. We find a compact clump of eight red supergiants and five other candidates at some distance, one of which is spectroscopically confirmed as a red supergiant. These objects must form an open cluster, which we name Alicante 8. Because of the high reddening and strong field contamination, the cluster sequence is not clearly seen in 2MASS or UKIDSS near-IR photometry. From the analysis of the red supergiants, we infer an extinction A K S = 1.9 and an age close to 20 Myr. Conclusions. Though this cluster is smaller than the three known previously, its properties still suggest a mass in excess of 10 000 M . Its discovery corroborates the hypothesis that star formation in this region has happened on a wide scale between ∼10 and ∼20 Myr ago.

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Section: The Cluster Against the Backgroundmentioning

confidence: 93%

Another cluster of red supergiants close to RSGC1

Negueruela¹,

González-Fernández²,

Marco³

et al. 2010

A&A

106

View full text Add to dashboard Cite

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“…fitting reveals an optical extinction of A V = 5.2 (Joshi et al 2008;. The optical UBVRI photometry for these stars is taken from Joshi et al (2008), and is complemented with near-and mid-IR photometry from 2MASS (Skrutskie et al 2006) and MSX (Egan et al 2003). The I-band photometry has been converted from the Cousins to the Johnson system (see Appendix).…”

Section: Ngc 7419mentioning

confidence: 99%

The initial masses of the red supergiant progenitors to Type II supernovae

Davies

Beasor

2017

Monthly Notices of the Royal Astronomical Society

122

156

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There are a growing number of nearby SNe for which the progenitor star is detected in archival pre-explosion imaging. From these images it is possible to measure the progenitor's brightness a few years before explosion, and ultimately estimate its initial mass. Previous work has shown that II-P and II-L supernovae (SNe) have Red Supergiant (RSG) progenitors, and that the range of initial masses for these progenitors seems to be limited to ∼ <17M ⊙ . This is in contrast with the cutoff of 25-30M ⊙ predicted by evolutionary models, a result which is termed the 'Red Supergiant Problem'. Here we investigate one particular source of systematic error present in converting pre-explosion photometry into an initial mass, that of the bolometric correction (BC) used to convert a single-band flux into a bolometric luminosity. We show, using star clusters, that RSGs evolve to later spectral types as they approach SN, which in turn causes the BC to become larger. Failure to account for this results in a systematic underestimate of a star's luminosity, and hence its initial mass. Using our empirically motivated BCs we reappraise the II-P and II-L SNe that have their progenitors detected in pre-explosion imaging. Fitting an initial mass function to these updated masses results in an increased upper mass cutoff of M hi =19.0 +2.5 −1.3 M ⊙ , with a 95% upper confidence limit of <27M ⊙ . Accounting for finite sample size effects and systematic uncertainties in the mass-luminosity relationship raises the cutoff to M hi =25M ⊙ (<33M ⊙ , 95% confidence). We therefore conclude that there is currently no strong evidence for 'missing' high mass progenitors to core-collapse SNe.

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“…We have now used our solution to derive ages and distances for the young clusters NGC 2547 (Naylor & Jeffries 2006) and NGC 2169 (Jeffries et al 2007), and consistent distances to some of the best‐studied star‐forming regions (Mayne & Naylor 2008). In Jeffries et al (2009), we derive distances to Vel OB2 and the association around γ Vel, and Joshi et al (2008) use our technique for measuring the distance to NGC 7419.…”

Section: Statisticsmentioning

confidence: 99%

Are pre-main-sequence stars older than we thought?

Naylor

2009

Monthly Notices of the Royal Astronomical Society

107

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We fit the colour-magnitude diagrams of stars between the zero-age main-sequence and terminal-age main sequence in young clusters and associations. The ages we derive are a factor 1.5 to 2 longer than the commonly used ages for these regions, which are derived from the positions of pre-main-sequence stars in colour-magnitude diagrams. From an examination of the uncertainties in the main-sequence and pre-main-sequence models, we conclude that the longer age scale is probably the correct one, which implies we must revise upwards the commonly used ages for young clusters and associations. Such a revision would explain the discrepancy between the observational lifetimes of proto-planetary discs and theoretical calculations of the time to form planets. It would also explain the absence of clusters with ages between 5 and 30Myr. We use the $\tau^2$ statistic to fit the main-sequence data, but find that we must make significant modifications if we are to fit sequences which have vertical segments in the colour-magnitude diagram. We present this modification along with improvements to methods of calculating the goodness-of-fit statistic and parameter uncertainties. Software implementing the methods described in this paper is available from http://www.astro.ex.ac.uk/people/timn/tau-squared/Comment: 13 pages, 9 figures, accepted form MNRA

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Multiwavelength study of a young open cluster NGC 7419

Abstract: Using new UBVRI Hα CCD photometric observations and the archival infrared and X-ray data, we have carried out a multi-wavelength study of a Perseus arm young galactic star cluster NGC 7419. An age of 22.5 ± 3.0 Myr and a distance of 3230

Cited by 17 publications

References 68 publications

Another cluster of red supergiants close to RSGC1

Another cluster of red supergiants close to RSGC1

The initial masses of the red supergiant progenitors to Type II supernovae

Are pre-main-sequence stars older than we thought?

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