Multiscale RBF Neural Network for Forecasting of Monthly Hake Catches off Southern Chile

Rodríguez, Nibaldo; Barba, Lida; Rubio, L Jose Miguel

doi:10.17562/pb-48-6

Cited by 4 publications

(3 citation statements)

References 17 publications

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“…Subsequent observations (Miroshnichenko et al , 2009(Miroshnichenko et al , 2011aBorges Fernandes et al 2009Rodríguez et al 2012;Polster et al 2012;Liermann et al 2014) and modeling (Carciofi et al 2010;Borges Fernandes et al 2011) of FS CMa stars have not been capable of unraveling the enigmatic nature of these objects. One of the most puzzling issues refers to the observationally inferred mass-loss rates, which are 2-3 dex higher than predicted by wind theory for B-type main-sequence stars.…”

Section: Introductionmentioning

confidence: 99%

First detections of FS Canis Majoris stars in clusters

Fuente

Najarro

Trombley

et al. 2015

A&A

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Section: Introductionmentioning

confidence: 99%

First detections of FS Canis Majoris stars in clusters

Fuente

Najarro

Trombley

et al. 2015

A&A

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“…There is a bright compact radio continuum source associated with MWC 922, which has been studied by Rodríguez et al (2012) using a 0 . 95 × 0 .…”

Section: Mwc 922mentioning

confidence: 99%

A pilot search for mm-wavelength recombination lines from emerging ionized winds in pre-planetary nebulae candidates

Contreras

Báez-Rubio

Alcolea

et al. 2017

A&A

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We report the results from a pilot search for radio recombination line (RRL) emission at millimeter wavelengths in a small sample of pre-planetary nebulae (pPNe) and young PNe (yPNe) with emerging central ionized regions. Observations of the H30α, H31α, H39α, H41α, H48β, H49β, H51β, and H55γ lines at ∼1 and ∼3 mm have been performed with the IRAM 30 m radio telescope. These lines are excellent probes of the dense inner ( 150 au) and heavily obscured regions of these objects, where the yet unknown agents for PN-shaping originate. We detected mm-RRLs in three objects: CRL 618, MWC 922, and M 2-9. For CRL 618, the only pPN with previous published detections of H41α, H35α, and H30α emission, we find significant changes in the line profiles indicating that current observations are probing regions of the ionized wind with larger expansion velocities and mass-loss rate than ∼29 yr ago. In the case of MWC 922, we observe a drastic transition from single-peaked profiles at 3 mm (H39α and H41α) to double-peaked profiles at 1 mm (H31α and H30α), which is consistent with maser amplification of the highest frequency lines; the observed line profiles are compatible with rotation and expansion of the ionized gas, probably arranged in a disk+wind system around a ∼5-10 M central mass. In M 2-9, the mm-RRL emission appears to be tracing a recent mass outburst by one of the stars of the central binary system. We present the results from non-LTE line and continuum radiative transfer models, which enables us to constrain the structure, kinematics, and physical conditions (electron temperature and density) of the ionized cores of our sample. We find temperatures T e ∼ 6000-17 000 K, mean densities n e ∼ 10 5 -10 8 cm −3 , radial density gradients n e ∝ r −αn with α n ∼ 2-3.5, and motions with velocities of ∼10-30 km s −1 in the ionized wind regions traced by these mm-wavelength observations. We deduce mass-loss rates ofṀ pAGB ≈ 10 −6 -10 −7 M yr −1 , which are significantly higher than the values adopted by stellar evolution models currently in use and would result in a transition from the asymptotic giant branch to the PN phase faster than hitherto assumed.

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“…Subsequent observations (Miroshnichenko et al 2007(Miroshnichenko et al , 2009(Miroshnichenko et al , 2011aBorges Fernandes et al 2009Rodríguez et al 2012;Polster et al 2012;Liermann et al 2014) and modeling (Carciofi et al 2010;Borges Fernandes et al 2011) of FS CMa stars have not been capable of unraveling the enigmatic nature of these objects. One of the most puzzling issues refers to the observationally inferred mass-loss rates, which are 2-3 dex higher than predicted by wind theory for B-type main-sequence stars.…”

Section: Introductionmentioning

confidence: 99%

First detections of FS Canis Majoris stars in clusters. Evolutionary state as constrained by coeval massive stars

de la Fuente,

Najarro,

Trombley

et al. 2014

Preprint

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Context. FS CMa stars are low-luminosity objects showing the B[e] phenomenon whose evolutionary state remains a puzzle. These stars are surrounded by compact disks of warm dust of unknown origin. Hitherto, membership of FS CMa stars to coeval populations has never been confirmed. Aims. The discovery of low-luminosity line emitters in the young massive clusters Mercer 20 and Mercer 70 prompts us to investigate the nature of such objects. We intend to confirm membership to coeval populations in order to characterize these emission-line stars through the cluster properties. Methods. Based on ISAAC/VLT medium-resolution spectroscopy and NICMOS/HST photometry of massive cluster members, new characterizations of Mercer 20 and Mercer 70 are performed. Coevality of each cluster and membership of the newly-discovered B[e] objects are investigated using our observations as well as literature data of the surroundings. Infrared excess and narrow-band photometric properties of the B[e] stars are also studied. Results. We confirm and classify 22 new cluster members, including Wolf-Rayet stars and blue hypergiants. Spectral types (O9-B1.5 V) and radial velocities of B[e] objects are compatible with the remaining cluster members, while emission features of Mg ii, Fe ii], and [Fe ii] are identified in their spectra. The ages of these stars are 4.5 and 6 Myr, and they show mild infrared excesses. Conclusions. We confirm the presence of FS CMa stars in the coeval populations of Mercer 20 and Mercer 70. We discuss the nature and evolutionary state of FS CMa stars, discarding a post-AGB nature and introducing a new hypothesis about mergers. A new search method for FS CMa candidates in young massive clusters based on narrow-band Paschen-α photometry is proposed and tested in photometric data of other clusters, yielding three new candidates.

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Multiscale RBF Neural Network for Forecasting of Monthly Hake Catches off Southern Chile

Cited by 4 publications

References 17 publications

First detections of FS Canis Majoris stars in clusters

First detections of FS Canis Majoris stars in clusters

A pilot search for mm-wavelength recombination lines from emerging ionized winds in pre-planetary nebulae candidates

First detections of FS Canis Majoris stars in clusters. Evolutionary state as constrained by coeval massive stars

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