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Here you would find a brief summary of the most important results of
scientific research carried out by our researchers during the last year,
presented by the observatory to the Department of Physical Sciences
of the RAS.
Access here the archives of our results from 1993.
Solar system
Archive of achievements, Solar system sector
Galaxy
Direct evidence of the fossil origin of large-scale magnetic fields of chemically
peculiar stars obtained
A spectropolarimetric survey of all chemically peculiar (CP) stars identified
in the Orion OB1 association of young stars has been performed with the 6-m BTA
telescope. The sample includes 56 CP stars aged 1-15 Myr having a common origin
within the association. 31 stars have magnetic fields stronger than 500 G
including 14 stars, whose fields have been found for the first time in our survey.
The analysis of the obtained data shows a decrease in the fraction of CP stars in
general and in the fraction of magnetic CP stars in particular with age, relative
to normal stars of the same type but without significant chemical anomalies. It was
found for the first time that no magnetic field is detected in objects younger than
1 Myr; later the structure of the star is rearranged and the magnetic field becomes
visible reaching a maximum at times of the order of 2-3 Myr and then drops by
a factor of 3 at times of the order of 10 Myr. The result obtained is a direct
and statistically reliable confirmation of the fossil origin of the magnetic
fields of stars of early spectral types.
Authors:
Semenko E.A. (National Astronomical Research Institute of Thailand), Romanyuk I.I.,
Yakunin I.A., Kudryavtsev D.O., Moiseeva A.V. (SAO RAS)
Published:
Semenko E., Romanyuk I., Yakunin I., Kudryavtsev D., Moiseeva A. Spectropolarimetry of magnetic
Chemically Peculiar stars in the Orion OB1 association, Monthly Notices of the
Royal Astronomical Society, 2022, Volume 515, Issue 1, pp. 998-1011
Discovery of new LBVs in the Local Volume galaxy NGC 1156
Luminous Blue Variables (LBVs) are a rare type of massive stars with high luminosity
and strong photometric and spectroscopic variability. Clarification of the nature
and evolutionary status of LBVs requires a significant expansion of the sample
of known and studied stars of this type. In the galaxy NGC1156, we discovered
two massive stars with emission spectra which, according to the results of
spectroscopy and photometric monitoring at the 6-m SAO RAS telescope (BTA)
and the 2.5-m telescope of the Caucasian Mountain Observatory of SAI MSU,
are classified as LBVs. During the observation program at the BTA aimed at
searching for LBVs in the Local Volume, our research team discovered and
confirmed the status of 5 LBVs, while in total about 20 stars of this type
are known at such distances. Modeling the spectral energy distributions and
spectra of two detected LBVs made it possible to determine their bolometric
luminosities (8×105 and 1.6×106 of solar luminosities with the 10% accuracy),
photosphere temperatures (<7000 K for the fainter and 7900±400 K for the
brighter star). Both stars have extremely large radii for LBVs, 650-680 solar radii.
Authors:
Solovyeva Yu. N., Vinokurov A.S., Tikhonov N.A., Kostenkov A.E., Sarkisyan A.N.,
Dedov E.O., Moiseev A.V., Oparin D.V. (SAO RAS) in cooperation with Atapin K.E.
(SAO RAS, SAI MSU), Fabrika S.N. (SAO RAS, KFU), Valeev A.F. (SAO RAS, CrAO RAS)
Published:
1. Solovyeva, A. Kostenkov, E. Dedov, A. Vinokurov. «Wind parameters of the new LBV in NGC1156»,
Proceedings of Science, 2022, accepted, arXiv:2209.06012v2;
2. Y. Solovyeva, A. Vinokurov, N. Tikhonov, A. Kostenkov, K. Atapin, A. Sarkisyan, A. Moiseev,
S. Fabrika, D. Oparin, A. Valeev. «Search for LBVs in the Local Volume galaxies: study of
two stars in NGC 1156», Monthly Notices of the Royal Astronomical Society, 2022, accepted,
arXiv:2208.05858v1
Archive of achievements, Galaxy sector
Metagalaxy
Discovery of a young and extremely metal poor dwarf galaxy
A nearby dwarf galaxy with an extremely low heavy element abundance has
been discovered. The gas-rich galaxy HIPASS J1131-31 with a radial velocity
of 716 km/s was detected as an emission source in the neutral hydrogen line
in the southern sky survey at the Parkes radio telescope. It was resolved
into individual stars in our observations with the Hubble Space Telescope.
The galaxy is concealed in such close proximity of a bright star that we
call it “hidden” (Peekaboo). The Peekaboo dwarf galaxy is located on the
outskirts of a galaxy group at a distance of 6.8±0.7 Mpc from us. The red
giant branch of the system is tenuous compared with the prominence of the
features of young populations in the color-magnitude diagram, inviting
speculation that star formation in the galaxy only began in the last few Gyr.
Spectral observations with the 10-meter South African telescope reveal
HIPASS J1131-31 to be one of the most extremely metal-poor galaxies known
with an oxygen abundance smaller than 2% of the Sun's. The proximity of
the discovered galaxy makes it an important target for further study
of the cosmic abundance of chemical elements and the nature of young
galaxies.
Authors:
Karachentsev I.D., Makarova L.N. (SAO RAS), Koribalski B.S. (Australia
Telescope National Facility; School of Science, Western Sydney University),
Anand G.S. (Space Telescope Science Institute), Tully R.B. (Institute for
Astronomy, University of Hawaii), Kniazev A.Y. (Southern African Large
Telescope Foundation; Sternberg Astronomical Institute, Lomonosov Moscow
State University)
Published:
Karachentsev I.D., Makarova L.N., Koribalski B.S., Anand G.S., Tully R.B.,
Kniazev A.Y., Peekaboo: the extremely metal poor dwarf galaxy HIPASS J1131-31,
Monthly Notices of the Royal Astronomical Society, 2022, DOI: 10.1093/mnras/stac3284
Unveiling of an unusual nitrogen-rich massive star in a metal-poor dwarf galaxy
While studying the ionized gas kinematics of the dwarf galaxy NGC 4068 with the
6-m SAO RAS telescope, a compact nebula with high velocity dispersion was
discovered. Follow-up spectroscopy performed at the 6-m and 2.5-m Caucasian
Mountain Observatory of SAI MSU telescopes has shown that there is a star at
the center of the nebula enriching the surrounding nebula with nitrogen,
so that the observed [N/O] ratio is almost solar, although in the gas
surrounding the galaxy itself, the abundance of heavier elements is only
1/10 of solar. Modeling with CMFGEN, a code for calculating expanding atmospheres,
has shown that we are talking about a massive star at a short stage of evolution
(a blue supergiant or a Wolf-Rayet star), when a powerful stellar wind actively
affects the environment. The bolometric luminosity of the star is
(1.5-1.7)·106 of solar, the estimated mass is about
80 solar masses. The radius of the surrounding expanding nebula is
smaller than 15 pc, and its kinematic age is smaller than 500,000 years.
Authors:
Yarovova A.D., Egorov O.V., Moiseev A.V., Maryeva O.V. (SAO RAS)
Published:
Yarovova A.D., Egorov O.V., Moiseev A.V., Maryeva O.V., Unveiling the
nitrogen-rich massive star in the metal-poor galaxy NGC 4068, Monthly Notices
of the Royal Astronomical Society, 2022, accepted, DOI: 10.1093/mnras/stac2949;
arXiv:2209.12522
Archive of achievements, Metagalaxy sector
Hardware and methodological developments
Increasing the accuracy of measurements in the long-term accumulation mode
at the RATAN-600
The mode of guidance of radio sources using a large reflection radio telescope
can significantly expand the capabilities of the instrument both for studying
the dynamics of variable objects and for implementing time accumulation in problems
requiring high sensitivity. To implement the tracking modes of the RATAN-600
radio telescope, it is necessary to introduce new automation instruments that
provide a new quality of monitoring and controlling the geometry of the antenna
system [1], [2], [3]. To solve these problems in 2020-2022, an automated control
system for the feed movement of type 3 was created and put into operation. The new
automated control system ensures the normal operating modes of the feed, and also,
due to the new possibilities for synchronous control of the movement of the carriage
and the feed cabin, allows developing new methods of observing with the South+Flat
antenna system. The structure of the automated control system is built using standard
(widely available) instruments that support the most common industrial protocols for
data exchange between the intelligent nodes of the complex, which makes it possible
to expand the functions of the complex with low upgrade costs for fitting the
automated control system with additional components of the distributed peripheral.
Authors:
Storozhenko A.A., Bogod V.M., Lebedev M.K., Ovchinnikova N.E., Khaikin V.B. (SAO RAS)
Published:
1. Storozhenko A.A., Lebedev M.K., Ovchinnikova N.E., Khaikin V.B. RATAN-600 Test Tracking
Modes for Observations of Fast Variable Processes on the Sun // Solar-Terrestrial Physics:
XXIII All-Russian Annual conf., Oct. 7-11 2019, Saint-Petersburg, Pulkovo: Proceedings –
2019. – Pp. 369-372. – DOI: 10.31725/0552-5829-2019-369-3722.
2. Storozhenko A.A., Lebedev M.K., Ovchinnikova N., Bogod V.M., Khaikin V.B., Ripak A.M.,
Pervakov A., Grechkin A. The Tracking Mode for the RATAN-600 Southern Sector with the
Periscope // Ground-Based Astronomy in Russia. 21st Century: Proc. of the All-Russian Conf.,
Nizhny Arkhyz, Russia, September 21-25, 2020. – Pyatigorsk, 2020. – P. 407-408. –
DOI: 10.26119/978-5-6045062-0-2 2020 407;
3. Storozhenko A.A., Bogod V.M., Lebedev M.K., Ovchinnikova N.E., Khaikin V.B., Pervakov A.A.,
Grechkin A.A. RATAN-600 receiving mirror automatic control system for tracking
mode // Solar-Terrestrial Physics – 2021: XXV All-Russian Annual conf. in Solar Physics,
October 4-8, 2021, GAO RAS, St. Petersburg. – 2021. – C. – 249-252. –
DOI: 10.31725/0552-5829-2021-249-252. –
(http://www.gaoran.ru/russian/solphys/2021/book/conf2021.pdf.)
Archive of achievements, Instrumental and Methodological Development sector
Archive of achievements, Astronomical education sector
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