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Title: THE NATURE AND EVOLUTIONARY STATE OF THE FU ORIONIS BINARY SYSTEM

Abstract

In this paper, we present the results of our adaptive optics fed three-dimensional imaging spectroscopy study of the FU Orionis binary system. Although the 0.''5 separation companion to FU Ori is {approx}4 mag fainter, we have easily spatially resolved it in the J, H, and K infrared bands and extract high signal-to-noise spectra of the two stellar components from 1.15 to 2.4 {mu}m. We derive a spectral type of K5{sup +2}{sub -1} for FU Ori S based on the stellar photospheric absorption features and find that it is an actively accreting young star (M-dot{sub acc}{approx} (2-3) Multiplication-Sign 10{sup -8} M{sub Sun} yr{sup -1}) that is likely gravitationally bound to FU Ori. We have found that the continuum shape of FU Ori S is not well fit by our spectral modeling process, and this results in a large uncertainty in the line-of-sight extinction to the star. Yet, by placing FU Ori S on the Hertzsprung-Russell diagram and comparing its estimated location with evolutionary models, we find that it is best fit as a {approx}1.2 M{sub Sun} star with a likely age of less than {approx}2 Myr. If we assume coevality of the stellar components, we have thus placed an estimated agemore » on the FU Ori system. Moreover, assuming the canonical model for the nature of FU Ori in that its optical and infrared absorption features arise primarily from the inner circumstellar disk around a {approx}0.3 M{sub Sun} star, we find that the fainter FU Ori S component is actually the more massive star in the system. Future monitoring of FU Ori S to investigate flux variability and orbital motion should further clarify the nature of this curious young binary.« less

Authors:
 [1];  [2]
  1. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  2. Institute for Astronomy, University of Hawaii, 640 North Aohoku Place, Hilo, HI 96720 (United States)
Publication Date:
OSTI Identifier:
22034699
Resource Type:
Journal Article
Journal Name:
Astronomical Journal (New York, N.Y. Online)
Additional Journal Information:
Journal Volume: 143; Journal Issue: 3; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-3881
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ACCRETION DISKS; ASTRONOMY; ASTROPHYSICS; BINARY STARS; COMPUTERIZED SIMULATION; EMISSION SPECTROSCOPY; HERTZSPRUNG-RUSSELL DIAGRAM; INFRARED SPECTRA; MAIN SEQUENCE STARS; MONITORING; NOISE; OPTICS; THREE-DIMENSIONAL CALCULATIONS

Citation Formats

Beck, Tracy L, and Aspin, C. THE NATURE AND EVOLUTIONARY STATE OF THE FU ORIONIS BINARY SYSTEM. United States: N. p., 2012. Web. doi:10.1088/0004-6256/143/3/55.
Beck, Tracy L, & Aspin, C. THE NATURE AND EVOLUTIONARY STATE OF THE FU ORIONIS BINARY SYSTEM. United States. https://doi.org/10.1088/0004-6256/143/3/55
Beck, Tracy L, and Aspin, C. Thu . "THE NATURE AND EVOLUTIONARY STATE OF THE FU ORIONIS BINARY SYSTEM". United States. https://doi.org/10.1088/0004-6256/143/3/55.
@article{osti_22034699,
title = {THE NATURE AND EVOLUTIONARY STATE OF THE FU ORIONIS BINARY SYSTEM},
author = {Beck, Tracy L and Aspin, C},
abstractNote = {In this paper, we present the results of our adaptive optics fed three-dimensional imaging spectroscopy study of the FU Orionis binary system. Although the 0.''5 separation companion to FU Ori is {approx}4 mag fainter, we have easily spatially resolved it in the J, H, and K infrared bands and extract high signal-to-noise spectra of the two stellar components from 1.15 to 2.4 {mu}m. We derive a spectral type of K5{sup +2}{sub -1} for FU Ori S based on the stellar photospheric absorption features and find that it is an actively accreting young star (M-dot{sub acc}{approx} (2-3) Multiplication-Sign 10{sup -8} M{sub Sun} yr{sup -1}) that is likely gravitationally bound to FU Ori. We have found that the continuum shape of FU Ori S is not well fit by our spectral modeling process, and this results in a large uncertainty in the line-of-sight extinction to the star. Yet, by placing FU Ori S on the Hertzsprung-Russell diagram and comparing its estimated location with evolutionary models, we find that it is best fit as a {approx}1.2 M{sub Sun} star with a likely age of less than {approx}2 Myr. If we assume coevality of the stellar components, we have thus placed an estimated age on the FU Ori system. Moreover, assuming the canonical model for the nature of FU Ori in that its optical and infrared absorption features arise primarily from the inner circumstellar disk around a {approx}0.3 M{sub Sun} star, we find that the fainter FU Ori S component is actually the more massive star in the system. Future monitoring of FU Ori S to investigate flux variability and orbital motion should further clarify the nature of this curious young binary.},
doi = {10.1088/0004-6256/143/3/55},
url = {https://www.osti.gov/biblio/22034699}, journal = {Astronomical Journal (New York, N.Y. Online)},
issn = {1538-3881},
number = 3,
volume = 143,
place = {United States},
year = {2012},
month = {3}
}