L. Hernández-Martínez

Universidad Nacional Autónoma de México

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

A. Rodríguez‐González

Universidad Nacional Autónoma de México

M. Peña

Universidad Nacional Autónoma de México

J. Cantó

Universidade Federal do Rio de Janeiro

A. C. Raga

Universidad Nacional Autónoma de México

A. Castellanos-Ramírez

Instituto de Geofísica y Astronomía

A. Esquivel

Universidad Nacional Autónoma de México

P. R. Rivera-Ortíz

Université Grenoble Alpes

J. García–Rojas

Instituto de Astrofísica de Canarias

Leticia Carigi

Universidad Nacional Autónoma de México

P. F. Velázquez

Universidad Nacional Autónoma de México

Cooperative Institutions

Universidad Nacional Autónoma de México

Instituto Nacional de Investigaciones Nucleares

Instituto de Geofísica y Astronomía

National Institute of Astrophysics, Optics and Electronics

Centre National de la Recherche Scientifique

Consejo Nacional de Investigaciones Científicas y Técnicas

Instituto de Astrofísica de Canarias

Université Paris Cité

Délégation Paris 7

Max Planck Society

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

VizieR Online Data Catalog: PN and HII regions in NGC6822 (Hernandez-Martinez+, 2009)

yCat (2009)

L. Hernández-Martínez M. Peña

Source

Cite

Citations (0)

Modelling the CO streamers in the explosive ejection of Orion BN/KL region

Monthly Notices of the Royal Astronomical Society (2022)

A. Rodríguez-González P. R. Rivera-Ortíz A. Castellanos-Ramírez A. C. Raga L. Hernández-Martínez

ABSTRACT We present reactive gasdynamic, axisymmetric simulations of dense, high-velocity clumps for modelling the CO streamers observed in Orion BN/KL. We have considered 15 chemical species, a cooling function for atomic and molecular gas, and heating through cosmic rays. Our numerical simulations explore different ejection velocities, interstellar medium density configurations, and CO content. Using the CO density and temperature, we have calculated the CO (J = 2 → 1) emissivity, and have built CO maps and spatially resolved line profiles, allowing us to see the CO emitting regions of the streamers and to obtain position velocity diagrams to compare with observations. We find that in order to reproduce the images and line profiles of the BN/KL CO streamers and H2 fingers, we need to have clumps that first travel within a dense cloud core, and then emerge into a lower-density environment.

Orion Nebula

Line (geometry)

10.1093/mnras/stac3793

Cite

Citations (2)

Chemical evolution models for NGC 6822 using planetary nebulae abundances

Proceedings of the International Astronomical Union (2011)

L. Hernández-Martínez Leticia Carigi M. Peña M. Peimbert

Abstract We present chemical evolution models for the dwarf irregular NGC 6822, using chemical abundances of Planetary Nebulae (PNe) and HII regions and also the mass of gas (M gas ) as observational constraints. Chemical evolution models have been calculated to reproduce the abundances as derived from both, collisionally excited lines (CELs) and recombination lines (RLs). In our models, the chemical contribution of low and intermediate mass stars (LIMS) is time delayed, while for the massive stars the chemical contribution is instantaneous, as in Franco & Carigi (2008). The chemical contribution of SNIa is included in our model, thus we are also able to reproduce the observational Fe/H abundance obtained from A stars.

Chemical evolution

10.1017/s1743921312011556

Cite

Citations (0)

The initial physical conditions of the Orion BN/KL fingers

arXiv (Cornell University) (2019)

P. R. Rivera-Ortíz A. Rodrı́guez-González L. Hernández-Martínez J. Cantó Luis Alberto Zapata

Orion BN/KL is an example of a poorly understood phenomena in star forming regions involving the close encounter of young stellar objects. The explosive structure, the great variety of molecules observed, the energy involved in the event and the mass of the region suggest a contribution in the {chemical diversity} of the local interstellar medium. Nevertheless, the frequency and duration of other events like this have not been determined. In this paper, we explore a recent analytic model that takes into account the interaction of a clump with its molecular environment. We show that the widespread kinematic ages of the Orion fingers -- 500 to 4000 years -- is a consequence of the interaction of the explosion debris with the surrounding medium. This model explains satisfactorily the age discrepancy of the Orion fingers, and infers the initial conditions together with the lifetime of the explosion. Moreover, our model can explain why some CO streamers do not have a H$_2$ finger associated.

Source

Cite

Citations (0)

The two modes of PNLF

L. Hernández-Martínez A. Rodrı́guez-González A. Esquivel M. Peña A. C. Raga

Source

Cite

Citations (0)

Velocity segregation in a clump-like outflow with a non-top hat velocity cross-section

arXiv (Cornell University) (2021)

A. Castellanos-Ramírez A. C. Raga J. Cantó A. Rodrı́guez-González L. Hernández-Martínez

High velocity joined to the outflow source by emission with a Hubble ramp of linearly increasing radial velocity vs. distance are observed in some planetary nebulae and in some outflows in star formation regions. We propose a simple model in which a clump is ejected from a source over a period $\tau_0$, with a strong axis to edge velocity stratification. This non-top hat cross section results in the production of a highly curved working surface (initially being pushed by the ejected material, and later coasting along due to its inertia). From both analytic models and numerical simulations we find that this working surface has a linear velocity vs. position ramp, and therefore reproduces in a qualitative way the Hubble law clumps in planetary nebulae and outflows from young stars.

Outflow

Stratification (seeds)

Radial velocity

Position (finance)

Source

Cite

Citations (0)

PNe as observational constraints in chemical evolution models for NGC 6822

arXiv (Cornell University) (2011)

L. Hernández-Martínez Leticia Carigi M. Peña M. Peimbert

Chemical evolution models are useful for understanding the formation and evolution of stars and galaxies. Model predictions will be more robust as more observational constraints are used. We present chemical evolution models for the dwarf irregular galaxy NGC 6822 using chemical abundances of old and young Planetary Nebulae (PNe) and \ion{H}{ii} regions as observational constraints. Two sets of chemical abundances, one derived from collisionally excited lines (CELs) and one, from recombination lines (RLs), are used. We try to use our models as a tool to discriminate between both procedures for abundance determinations. In our chemical evolution code, the chemical contribution of low and intermediate mass stars is time delayed, while for the massive stars the chemical contribution follows the instantaneous recycling approximation. Our models have two main free parameters: the mass-loss rate of a well-mixed outflow and the upper mass limit, $M_{up}$, of the initial mass function (IMF). To reproduce the gaseous mass and the present-day O/H value we need to vary the outflow rate and the $M_{up}$ value.

Outflow

Chemical evolution

Initial mass function

Source

Cite

Citations (0)

PROPER MOTIONS OF THE HH 1 JET

Revista Mexicana de Astronomía y Astrofísica (2017)

A. C. Raga Bo Reipurth A. Esquivel A. Castellanos-Ramírez P. F. Velázquez

Proper motion

Source

Cite

Citations (1)

A Tail of Two Clumps

Galaxies (2022)

A. C. Raga J. Cantó A. Castellanos-Ramírez Jorge Ivan Castorena L. Hernández-Martínez

We present two axisymmetric simulations of a high velocity clump in a photoionized region: one for the case of a uniform, low density environment and a second one for the case of a clump first traveling within a high density medium and then emerging into a low density environment. We show that the second scenario results in the production of an axial tail of dense material with a linear velocity vs. position ramp (with zero velocity at the high/low density environment transition). This material comes from a confined bow shock (produced by the clump when it was within the dense cloud) that emerges into the low environmental density region.

Position (finance)

10.3390/galaxies10010019

Cite

Citations (1)

The Initial Physical Conditions of the Orion BN/KL Fingers

The Astrophysical Journal (2019)

P. R. Rivera-Ortíz A. Rodrı́guez-González L. Hernández-Martínez J. Cantó Luis A. Zapata

Orion BN/KL is an example of a poorly understood phenomena in star-forming regions involving the close encounters of young stellar objects. The explosive structure, the great variety of molecules observed, the energy involved in the event, and the mass of the region suggest a contribution to the chemical diversity of the local interstellar medium. Nevertheless, the frequency and duration of other, similar events have not been determined. In this paper, we explore a recent analytic model that takes into account the interaction of a clump with its molecular environment. We show that the widespread kinematic ages of the Orion fingers—500 to 4000 yr—are a consequence of the interaction of the explosion debris with the surrounding medium. This model explains satisfactorily the age discrepancy of the Orion fingers, and infers the initial conditions together with the lifetime of the explosion. Moreover, our model can explain why some CO streamers do not have an associated H2 finger.

Orion Nebula

10.3847/1538-4357/ab44b3

Cite

Citations (6)