RA Committee of Science Thematic Grant 21T-1C031 (2021-2023)

Young stellar objects with extreme outbursting activity

Though the astronomy as a science exists for several millennia, and its modern and most important branch - astrophysics - is developing for 150 years, the concept of the continuous star formation was proved by Ambartsumian only about 70 years ago. In the present time, when by the efforts of all astronomical community and by various methods many thousands of young stars were found. Now it is well established that the main factor, which defines the general characteristics and life span of a newly-formed star, is its mass.

This proposal suggests the enlarged studies of the one most enigmatic and rare phenomenon, observed in the pre-main-sequence stage of the stellar evolution, namely the powerful eruptions and outbursts of FUor and EXor objects. The proposed program includes the searches, monitoring and the spectral studies of the eruptive stars and little-studied infrared sources in the dark clouds.


Research Team


Tigran Magakian
PI; DSc
Principal research associate
Tigran Movsessian
PhD
Leading research associate
Hasmik Andreasyan
PhD
Research associate
Karen Gigoyan
Assistant astronomer


The outline of the suggested research program

  • The monitoring of already known but little-studied eruptive stars and of probable candidates to detect new outbursts;
  • The search of possible eruptions in the promising fields (especially in the isolated star formation regions having little attention);
  • Spectral studies of stellar sources, selected by their morphology, colors/ variability etc., particularly with the aim to compare their spectra in different levels of brightness;
  • The search of matter outflow from the stellar sources in optical and infrared ranges;
  • Direct imaging and/or spectroscopy of selected IRAS sources with aim to find the evidences of collimated outflows, abrupt light variations etc.
  • The analysis of the obtained data involving the observations in other spectral ranges, available by the means of virtual observatories;
  • The preparation and publication of the papers; presentation of the results in international symposia.

    • This program envisages collaborative work with Special Astrophysical Observatory (Russia), Sternberg Astronomical Institute (Moscow, Russia) and University of Colorado (USA).



    Research methods and techniques

    For the observations in Byurakan we plan to use 1-meter Schmidt telescope (105/135/213). This is one of the largest Schmidt telescopes in the world. In 2013-2015 it was completely refurbished by groups of Russian and Armenian experts.
    The spectral observations will be performed with the 6-m telescope of SAO RAS, using the SCORPIO-2 multi-mode focal reducer in the mode of long-slit spectroscopy. The spectral ranges and resolution will be 3650-7250 Å, R=3000 and 5000-7250 Å, R= 6000.
    The observations in near-IR range, oriented especially for the detection of molecular hydrogen outflows, will be conducted with our collaborators on the 2.5 m telescope of the Southern Station of SAI at the Northern Caucasus.


    Goals and Expected Results

  • The lightcurves of the selected eruptive stars and of the newly found ones.
  • Concerning the latter ones, we expect to find probable new high-amplitude outbursting events, perhaps new EXors and intermediate objects.
  • The more or less full spectroscopic coverage of the outbursts which will allow to trace the matter ejection intensity and velocity during the eruption.
  • The clarifying of the nature of the certain embedded IR sources, connected with outflows.
  • Finding of new extended outflows, which can keep the history of the outbursting events in the various timescales. Though this opinion is shared by many researchers, it is difficult to associate specific eruptive/outburst events with knots or augmented ejection along the flows. However, it became possible at least in two cases: for Z CMa and V2494 Cyg; one can expect further examples.
  • Finding of new molecular hydrogen flows in the darkest areas of star-forming regions.
  • Clarification and possible expansion of the list of FUors, EXors and intermediate objects.


    • Published Papers

  • Magakian, T. Yu.; Tatarnikov, A. M.; Movsessian, T. A.; Andreasyan, H. R. 2022 - Near-infrared detection of H2 flows in the core of the Mon R1 association // MNRAS, 510 2, 2139-2146, ADS
  • Movsessian, T. A.; Magakian, T. Yu.; Dodonov, S. N.; Andreasyan, H. R. 2021 - Narrow band imaging survey of dark clouds // ComBAO, 68 2, 436-440, ADS