Lorena Arias

FITspec: A New Algorithm for the Automated Fit of Synthetic Stellar Spectra for OB Stars

In this paper we describe the FIT\textit{spec} code, a data mining tool for the automatic fitting of synthetic stellar spectra. The program uses a database of 27\,000 {\sc cmfgen} models of stellar atmospheres arranged in a six-dimensional (6D) space, where each dimension corresponds to one model parameter. From these models a library of 2\,835\,000 synthetic spectra were generated covering the ultraviolet, optical, and infrared region of the electromagnetic spectrum. Using FIT\textit{spec} we adjust the effective temperature and the surface gravity. From the 6D array we also get the luminosity, the metallicity, and three parameters for the stellar wind: the terminal velocity (

Database of CMFGEN Models in a 6-Dimensional Space

v_\infty

Galaxies: The Third Dimension

), the

Galaxy evolution in groups: NGC 3447/NGC 3447A: the odd couple in LGG 225⋆

\beta

Planetary Nebulae with H2 Emission

exponent of the velocity law, and the clumping filling factor (

Analysis and fit of stellar spectra using a mega-database of CMFGEN models

F_{\rm cl}

NIR Fabry-Perot Imaging Spectroscopy of PNe

). Finally, the projected rotational velocity (

The Radial Velocity Profiles of some Proplyds in the Orion Nebula

v\cdot\sin i

Planetary Nebulae, Bubbles and Superbubbles: What Can We Learn From Their Kinematics?

) can be obtained from the library of stellar spectra. Validation of the algorithm was performed by analyzing the spectra of a sample of eight O-type stars taken from the {\sc iacob} spectroscopic survey of Northern Galactic OB stars. The spectral lines used for the adjustment of the analyzed stars are reproduced with good accuracy. In particular, the effective temperatures calculated with the FIT\textit{spec} are in good agreement with those derived from spectral type and other calibrations for the same stars. The stellar luminosities and projected rotational velocities are also in good agreement with previous quantitative spectroscopic analyses in the literature. An important advantage of FIT\textit{spec} over traditional codes is that the time required for spectral analyses is reduced from months to a few hours.

Protoplanetary Disks in the Orion Nebula: An H

We present a database of 25,000 atmospheric models (which is to grow to a grand total of 75000 models by the conclusion of the project) with stellar masses between 9 and 120 M\(_{\odot }\), covering the region of the OB main sequence and W-R stars in the H–R diagram. The models were calculated using the ABACUS I supercomputer and the stellar atmosphere code CMFGEN. The parameter space has 6 dimensions: surface temperature of the star, also called the effective temperature (\(T_\mathrm{eff}\)), luminosity (L), metallicity (Z), and three stellar wind parameters, the exponent (\(\beta \)) of the wind velocity law, the terminal velocity (\(V_{\infty }\)), and the volume filling factor (\(F_{cl}\)). For each model, we also calculate synthetic spectra in the UV (900–2,000 A), optical (3,500–7,000 A), and near IR (10,000–30,000 A) ranges. For comparison with observations, the synthetic spectra were rotationally broaden using ROTIN3, by covering the range between 10 and 350 km s\(^{-1}\) with steps of 10 km s\(^{-1}\), resulting a library of 1,575,000 synthetic spectra.