Publication Abstracts

Alcolea et al. 1999

Alcolea, J., J.R. Pardo, V. Bujarrabal, R. Bachiller, A. Barcia, F. Colomer, J.D. Gallego, J. Gómez-González, A. del Pino Cisneros, P. Planesas, S. del Río, A. Rodríguez-Franco, A. del Romero, M. Tafalla, and P. de Vicente, 1999: Six years of short-spaced monitoring of the v=1 and v=2, J=1-0 28SiO maser emission in evolved stars. Astron. Astrophys. Supp. Series, 139, 461-482.

We present the results from a monitoring of the v=1 and v=2, J=1-0 28SiO maser emission in 21 objects, covering all types of known SiO maser emitters: 13 Mira variables, 2 long period semiregulars (SRGs), 3 variable supergiants (SGs), 2 OH/IR stars, and one young stellar object. This study has been carried out with the 13.7 meter radiotelescope of the Centro Astronómico de Yebes (Guadalajara, Spain), from July 1984 to May 1990, and represents the longest and most tightly sampled monitoring of SiO masers ever published.

Our data show that for Mira-type (i.e. regular) variables, the SiO and optical light curves agree in period, and that the maxima of the SiO emission lag the optical ones by about 0.1-0.2 periods. Since a similar lag characterizes the near infrared (NIR) emission variability from these stars, we conclude that for regular variables SiO and NIR vary in phase. This result was confirmed in three objects for which NIR variability curves are available. For SRGs and SGs, we found a less systematic behavior, but when the SiO emission is periodic, its variability curve agrees with the optical one, also showing a lag between maximum epochs similar to that of Mira-type stars. The data clearly reveal other interesting details on the SiO maser variability, such as the strong intensity differences between different maxima and changes in the velocity distribution of the emission. Finally, the SiO masers associated to the young stellar object Orion IRc2 showed a double peaked spectrum with low amplitude, aperiodic variations.

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BibTeX Citation

@article{al04300u,
  author={Alcolea, J. and Pardo, J. R. and Bujarrabal, V. and Bachiller, R. and Barcia, A. and Colomer, F. and Gallego, J. D. and Gómez-González, J. and del Pino Cisneros, A. and Planesas, P. and del Río, S. and Rodríguez-Franco, A. and del Romero, A. and Tafalla, M. and de Vicente, P.},
  title={Six years of short-spaced monitoring of the v=1 and v=2, J=1-0 28SiO maser emission in evolved stars},
  year={1999},
  journal={Astron. Astrophys. Supp. Series},
  volume={139},
  pages={461--482},
}

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RIS Citation

TY  - JOUR
ID  - al04300u
AU  - Alcolea, J.
AU  - Pardo, J. R.
AU  - Bujarrabal, V.
AU  - Bachiller, R.
AU  - Barcia, A.
AU  - Colomer, F.
AU  - Gallego, J. D.
AU  - Gómez-González, J.
AU  - del Pino Cisneros, A.
AU  - Planesas, P.
AU  - del Río, S.
AU  - Rodríguez-Franco, A.
AU  - del Romero, A.
AU  - Tafalla, M.
AU  - de Vicente, P.
PY  - 1999
TI  - Six years of short-spaced monitoring of the v=1 and v=2, J=1-0 28SiO maser emission in evolved stars
JA  - Astron. Astrophys. Supp. Series
VL  - 139
SP  - 461
EP  - 482
ER  -

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