Abstract
RATAN-600 observations of a microwave source located above the active region NOAA 10105 obtained on September 7–20, 2002 with a frequency resolution of ∼10% have revealed a spectral feature near 3.04 cm that can be interpreted as a neutral hydrogen line. This feature was observed September 11, 2002, in both absorption and emission, and was detected in the spectra of various portions of the source (sunspot, flocculus, and background). The maximum line depth of (35 ± 5)% of the source brightness was observed at the start of the observations (9.2h UT) in the flocculus in absorption. The line intensity decreased rapidly with time, becoming less than the measurement errors by 9.7h UT. It is most likely that the 3.04 cm emission is related to a 2B chromospheric flare (M2.2 X-ray burst) observed at ∼7.5h UT in the floccular field, near the main sunspot of NOAA 10105. In this case, the total duration of the event was about two hours. These observations are consistent with earlier statistical studies, and refines these based on data with higher spatial resolution. Recommendations for further observational studies of the solar 3.04-cm hydrogen line are presented; requirements for theories of the 3.04 cm line taking into account nonequilibrium states of the active-region plasma are indicated.
Similar content being viewed by others
References
J. P. Wild, Astrophys. J. 115, 206 (1952).
C. De Jager, in Paris Symposium on Radio Astronomy, Ed. by R. N. Bracewell (Stanford Univ., Stanford, 1959), p. 96.
A. Zelenka, Solar Phys. 58, 17 (1978).
V. V. Zheleznyakov, Radio Emission of the Sun and Planets (Nauka, Moscow, 1964), p. 70 [in Russian].
A. F. Dravskikh, Izv. Glavn. Astron. Observ. Pulkovo 164, 128 (1960).
A. F. Dravskikh, Izv. Glavn. Astron. Observ. Pulkovo 172, 40 (1964).
A. F. Dravskikh and Z. V. Dravskikh, Preprint Spets. Astrofiz. Observ. No. 42L (1987).
A. F. Dravskikh and Z. V. Dravskikh, Astron. Zh. 65, 199 (1988) [Sov. Astron. 32, 104 (1988)].
V. M. Bogod, V. I. Garaimov, V. A. Shatilov, et al., in Proceedings of the 27th Radioastronomical Conference, Vol. 3 (IPA RAN, St. Petersburg, 1997), p. 132.
V. M. Bogod, A. M. Alesin, S. V. Baldin, et al., in Proceedings of the 9th Pulkovo International Conference on Solar Physics (GAO RAN, Pulkovo, 2005), p. 627.
N. G. Peterova, N. A. Topchilo, and T. P. Borisevich, in Proceedings of the All-Russia Annual Conference on Solar Physics (GAO RAN, Pulkovo, 2009), p. 337.
V. I. Garaimov, Preprint Spets. Astrofiz. Observ. No. 127T (1997).
N. A. Topchilo, N. G. Peterova, and T. P. Borisevich, Astron. Zh. 87, 75 (2010) [Astron. Rep. 54, 69 (2010)].
R. T. Stewart, M. K. McCabe, M. J. Koomen, et al., Solar Phys. 36, 203 (1974).
D. M. Rust and E. Hildner, Solar Phys. 48, 381 (1976).
A. M. Uralov, S. V. Lesovoi, V. G. Zandanov, et al., Solar Phys. 208, 69 (2002).
N. N. Kardapolova, T. P. Borisevich, N. G. Peterova, et al., Astron. Zh. 85, 460 (2008) [Astron. Rep. 52, 409 (2008)].
R. A. Mewald, R. A. Leske, E. C. Stone, et al., Astrophys. J. 693, L11 (2009).
V. V. Zaitsev and A. V. Stepanov, Astron. Zh. 68, 384 (1991) [Sov. Astron. 35, 189 (1991)].
Author information
Authors and Affiliations
Additional information
Original Russian Text © N.G. Peterova, N.A. Topchilo, T.P. Borisevich, 2011, published in Astronomicheskii Zhurnal, 2011, Vol. 88, No. 9, pp. 912–919.
Rights and permissions
About this article
Cite this article
Peterova, N.G., Topchilo, N.A. & Borisevich, T.P. Solar 3.04 cm hydrogen line emission revealed in observations of the active region NOAA 10105. Astron. Rep. 55, 841–848 (2011). https://doi.org/10.1134/S1063772911080087
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063772911080087