PERIODIC CHANGES IN THE ORIENTATION OF ORBITS AND THE AGE OF THE GALACTIC BAR
Section: STARS AND THE INTERSTELLAR MEDIUM
Authors:
1.
Sternberg Astronomical Institute, Lomonosov Moscow State University
Faculty of Physics, Lomonosov Moscow State University
Faculty of Physics, Lomonosov Moscow State University
2.
Sternberg Astronomical Institute, Lomonosov Moscow State University
Type:
Сonference article
Published:
27.12.2024
Subject area:
UDK 52 Астрономия. Геодезия
UDK 53 Физика
UDK 520 Инструменты, приборы и методы астрономических наблюдений, измерений и анализа
UDK 521 Теоретическая астрономия. Небесная механика. Фундаментальная астрономия. Теория динамической и позиционной астрономии
UDK 523 Солнечная система
UDK 524 Звезды и звездные системы. Вселенная Солнце и Солнечная система
UDK 52-1 Метод изучения
UDK 52-6 Излучение и связанные с ним процессы
GRNTI 41.00 АСТРОНОМИЯ
GRNTI 29.35 Радиофизика. Физические основы электроники
GRNTI 29.31 Оптика
GRNTI 29.33 Лазерная физика
GRNTI 29.27 Физика плазмы
GRNTI 29.05 Физика элементарных частиц. Теория полей. Физика высоких энергий
OKSO 03.06.01 Физика и астрономия
OKSO 03.05.01 Астрономия
OKSO 03.04.03 Радиофизика
BBK 2 ЕСТЕСТВЕННЫЕ НАУКИ
BBK 223 Физика
TBK 614 Астрономия
TBK 6135 Оптика
BISAC SCI004000 Astronomy
BISAC SCI005000 Physics / Astrophysics
UDK 53 Физика
UDK 520 Инструменты, приборы и методы астрономических наблюдений, измерений и анализа
UDK 521 Теоретическая астрономия. Небесная механика. Фундаментальная астрономия. Теория динамической и позиционной астрономии
UDK 523 Солнечная система
UDK 524 Звезды и звездные системы. Вселенная Солнце и Солнечная система
UDK 52-1 Метод изучения
UDK 52-6 Излучение и связанные с ним процессы
GRNTI 41.00 АСТРОНОМИЯ
GRNTI 29.35 Радиофизика. Физические основы электроники
GRNTI 29.31 Оптика
GRNTI 29.33 Лазерная физика
GRNTI 29.27 Физика плазмы
GRNTI 29.05 Физика элементарных частиц. Теория полей. Физика высоких энергий
OKSO 03.06.01 Физика и астрономия
OKSO 03.05.01 Астрономия
OKSO 03.04.03 Радиофизика
BBK 2 ЕСТЕСТВЕННЫЕ НАУКИ
BBK 223 Физика
TBK 614 Астрономия
TBK 6135 Оптика
BISAC SCI004000 Astronomy
BISAC SCI005000 Physics / Astrophysics
Language:
English
Keywords:
Galaxy: kinematics and dynamics
Abstract (English):
We studied the model of the Galaxy that reproduces the observed median velocity distribution derived from Gaia DR3 data along the Galactocentric distance, $R$. The model profiles of radial velocity, $V_R$, demonstrate an increase with a period of $P = 2.1 \pm{0.1}$ Gyr and form humps at $R = $ 6-7 kpc. The average amplitude of variation in the radial velocity is $A = 1.76 \pm{0.20}\, \rm km\, s^{-1}$. The humps are supported by orbits changing orientation relative to the major axis of the bar within the range of $[-45, \;45]$$^{\circ}$. The median period of variation in the angular momentum of hump-supporting orbits is $P = 1.85 \pm{0.17}$ Gyr, and 71.6 % of them support ring $R_2$. The observed profile does not show any humps. In the model profile, humps disappear during the times $2.5 \pm{0.3}$ and $4.5 \pm{0.5}$ Gyr, indicating that the age of the Galactic bar must be close to one of these values. The model disk forms outer resonance rings $R_1$ and $R_2$, which demonstrate periodic changes in their morphology with a period of $P = 2.0\pm{0.1}$ Gyr, supported by orbits trapped by the Outer Lindblad Resonance.
We studied the model of the Galaxy that reproduces the observed median velocity distribution derived from Gaia DR3 data along the Galactocentric distance, $R$. The model profiles of radial velocity, $V_R$, demonstrate an increase with a period of $P = 2.1 \pm{0.1}$ Gyr and form humps at $R = $ 6-7 kpc. The average amplitude of variation in the radial velocity is $A = 1.76 \pm{0.20}\, \rm km\, s^{-1}$. The humps are supported by orbits changing orientation relative to the major axis of the bar within the range of $[-45, \;45]$$^{\circ}$. The median period of variation in the angular momentum of hump-supporting orbits is $P = 1.85 \pm{0.17}$ Gyr, and 71.6 % of them support ring $R_2$. The observed profile does not show any humps. In the model profile, humps disappear during the times $2.5 \pm{0.3}$ and $4.5 \pm{0.5}$ Gyr, indicating that the age of the Galactic bar must be close to one of these values. The model disk forms outer resonance rings $R_1$ and $R_2$, which demonstrate periodic changes in their morphology with a period of $P = 2.0\pm{0.1}$ Gyr, supported by orbits trapped by the Outer Lindblad Resonance.
Keywords:
Galaxy: kinematics and dynamics
Galaxy: kinematics and dynamics
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