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Title: GRAVITATIONALLY INDUCED DENSITY WAKE OF A CIRCULARLY ORBITING OBJECT AS AN INTERPRETATIVE FRAMEWORK OF UBIQUITOUS SPIRALS AND ARCS

Abstract

An orbiting object in a gas-rich environment creates a gravitational density wake containing information about the object and its orbit. Using linear perturbation theory, we analyze the observable properties of the gravitational wake due to the object circularly moving in a static homogeneous gaseous medium, in order to derive the Bondi accretion radius r{sub B} , the orbital distance r{sub p} , and the Mach number M{sub p} of the object. Supersonic motion, producing a wake of spiral-onion shell structure, exhibits a single-armed Archimedes spiral and two-centered circular arcs with respect to the line of sight. The pitch angle, arm width, and spacing of the spiral pattern are entirely determined by the orbital distance r{sub p} and Mach number M{sub p} of the object. The arm-interarm density contrast is proportional to r{sub B} , decreasing as a function of distance with a power index of -1. The background density distribution is globally changed from initially uniform to centrally concentrated. The vertical structure of the wake is manifested as circular arcs with the center at the object location. The angular extent of the arcs is determined by the Mach number M{sub p} of the object motion. Diagnostic probes of nonlinear wakesmore » such as a detached bow shock, the absence of the definite inner arm boundary, the presence of turbulent low-density eddies, and elongated shapes of arcs are explained in the extension of the linear analysis. The density enhancement at the center is always r{sub B} /r{sub p} independent of the nonlinearity, suggesting that massive objects can substantially modify the background distribution.« less

Authors:
 [1]
  1. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)
Publication Date:
OSTI Identifier:
21587451
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 739; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/739/2/102; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; DISTRIBUTION; HYDRODYNAMICS; MACH NUMBER; ORBITS; PERTURBATION THEORY; DIMENSIONLESS NUMBERS; FLUID MECHANICS; MECHANICS; PHYSICAL PROPERTIES; VELOCITY

Citation Formats

Kim, Hyosun, E-mail: hkim@asiaa.sinica.edu.tw. GRAVITATIONALLY INDUCED DENSITY WAKE OF A CIRCULARLY ORBITING OBJECT AS AN INTERPRETATIVE FRAMEWORK OF UBIQUITOUS SPIRALS AND ARCS. United States: N. p., 2011. Web. doi:10.1088/0004-637X/739/2/102; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Kim, Hyosun, E-mail: hkim@asiaa.sinica.edu.tw. GRAVITATIONALLY INDUCED DENSITY WAKE OF A CIRCULARLY ORBITING OBJECT AS AN INTERPRETATIVE FRAMEWORK OF UBIQUITOUS SPIRALS AND ARCS. United States. doi:10.1088/0004-637X/739/2/102; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Kim, Hyosun, E-mail: hkim@asiaa.sinica.edu.tw. Sat . "GRAVITATIONALLY INDUCED DENSITY WAKE OF A CIRCULARLY ORBITING OBJECT AS AN INTERPRETATIVE FRAMEWORK OF UBIQUITOUS SPIRALS AND ARCS". United States. doi:10.1088/0004-637X/739/2/102; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21587451,
title = {GRAVITATIONALLY INDUCED DENSITY WAKE OF A CIRCULARLY ORBITING OBJECT AS AN INTERPRETATIVE FRAMEWORK OF UBIQUITOUS SPIRALS AND ARCS},
author = {Kim, Hyosun, E-mail: hkim@asiaa.sinica.edu.tw},
abstractNote = {An orbiting object in a gas-rich environment creates a gravitational density wake containing information about the object and its orbit. Using linear perturbation theory, we analyze the observable properties of the gravitational wake due to the object circularly moving in a static homogeneous gaseous medium, in order to derive the Bondi accretion radius r{sub B} , the orbital distance r{sub p} , and the Mach number M{sub p} of the object. Supersonic motion, producing a wake of spiral-onion shell structure, exhibits a single-armed Archimedes spiral and two-centered circular arcs with respect to the line of sight. The pitch angle, arm width, and spacing of the spiral pattern are entirely determined by the orbital distance r{sub p} and Mach number M{sub p} of the object. The arm-interarm density contrast is proportional to r{sub B} , decreasing as a function of distance with a power index of -1. The background density distribution is globally changed from initially uniform to centrally concentrated. The vertical structure of the wake is manifested as circular arcs with the center at the object location. The angular extent of the arcs is determined by the Mach number M{sub p} of the object motion. Diagnostic probes of nonlinear wakes such as a detached bow shock, the absence of the definite inner arm boundary, the presence of turbulent low-density eddies, and elongated shapes of arcs are explained in the extension of the linear analysis. The density enhancement at the center is always r{sub B} /r{sub p} independent of the nonlinearity, suggesting that massive objects can substantially modify the background distribution.},
doi = {10.1088/0004-637X/739/2/102; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 739,
place = {United States},
year = {2011},
month = {10}
}