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Title: A KINE-CHEMICAL INVESTIGATION OF THE AB DOR MOVING GROUP 'STREAM'

Abstract

The AB Dor Moving Group consists of a 'nucleus' of {approx}10 stars at d {approx_equal} 20 pc, along with dozens of purported 'stream' members distributed across the sky. We perform a chemical and kinematic analysis of a subsample of AB Dor stream stars to test whether they constitute a physical stellar group. We use the NEMO Galactic kinematic code to investigate the orbits of the stream members, and perform a chemical abundance analysis using high resolution spectra taken with the Magellan Clay 6.5 m telescope. Using a {chi}{sup 2} test with the measured abundances for 10 different elements, we find that only half of the purported AB Dor stream members could possibly constitute a statistically chemically homogeneous sample. Some stream members with three-dimensional velocities were hundreds of parsecs from the AB Dor nucleus {approx}10{sup 8} yr ago, and hence were unlikely to share a common origin. We conclude that the published lists of AB Dor moving group stream members are unlikely to represent the dispersed remnant of a single star formation episode. A subsample of the stream stars appears to be both statistically chemically homogeneous and in the vicinity of the AB Dor nucleus at birth. Their mean metallicity ismore » [Fe/H] = 0.02 {+-} 0.02 dex, which we consider representative for the AB Dor group. Finally, we report a strong lower limit on the age of the AB Dor nucleus of >110 Myr based on the pre-main sequence contraction times for K-type members which have reached the main sequence.« less

Authors:
; ;  [1];  [2]
  1. University of Rochester, Department of Physics and Astronomy, Rochester, NY 14627-0171 (United States)
  2. Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287-1404 (United States)
Publication Date:
OSTI Identifier:
22167601
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 766; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; CHEMICAL ANALYSIS; CONTRACTION; COSMIC NUCLEI; ORBITS; RESOLUTION; SKY; SPECTRA; STARS; STELLAR FLARES; TELESCOPES; THREE-DIMENSIONAL CALCULATIONS

Citation Formats

Barenfeld, Scott A., Bubar, Eric J., Mamajek, Eric E., and Young, Patrick A.. A KINE-CHEMICAL INVESTIGATION OF THE AB DOR MOVING GROUP 'STREAM'. United States: N. p., 2013. Web. doi:10.1088/0004-637X/766/1/6.
Barenfeld, Scott A., Bubar, Eric J., Mamajek, Eric E., & Young, Patrick A.. A KINE-CHEMICAL INVESTIGATION OF THE AB DOR MOVING GROUP 'STREAM'. United States. doi:10.1088/0004-637X/766/1/6.
Barenfeld, Scott A., Bubar, Eric J., Mamajek, Eric E., and Young, Patrick A.. Wed . "A KINE-CHEMICAL INVESTIGATION OF THE AB DOR MOVING GROUP 'STREAM'". United States. doi:10.1088/0004-637X/766/1/6.
@article{osti_22167601,
title = {A KINE-CHEMICAL INVESTIGATION OF THE AB DOR MOVING GROUP 'STREAM'},
author = {Barenfeld, Scott A. and Bubar, Eric J. and Mamajek, Eric E. and Young, Patrick A.},
abstractNote = {The AB Dor Moving Group consists of a 'nucleus' of {approx}10 stars at d {approx_equal} 20 pc, along with dozens of purported 'stream' members distributed across the sky. We perform a chemical and kinematic analysis of a subsample of AB Dor stream stars to test whether they constitute a physical stellar group. We use the NEMO Galactic kinematic code to investigate the orbits of the stream members, and perform a chemical abundance analysis using high resolution spectra taken with the Magellan Clay 6.5 m telescope. Using a {chi}{sup 2} test with the measured abundances for 10 different elements, we find that only half of the purported AB Dor stream members could possibly constitute a statistically chemically homogeneous sample. Some stream members with three-dimensional velocities were hundreds of parsecs from the AB Dor nucleus {approx}10{sup 8} yr ago, and hence were unlikely to share a common origin. We conclude that the published lists of AB Dor moving group stream members are unlikely to represent the dispersed remnant of a single star formation episode. A subsample of the stream stars appears to be both statistically chemically homogeneous and in the vicinity of the AB Dor nucleus at birth. Their mean metallicity is [Fe/H] = 0.02 {+-} 0.02 dex, which we consider representative for the AB Dor group. Finally, we report a strong lower limit on the age of the AB Dor nucleus of >110 Myr based on the pre-main sequence contraction times for K-type members which have reached the main sequence.},
doi = {10.1088/0004-637X/766/1/6},
journal = {Astrophysical Journal},
number = 1,
volume = 766,
place = {United States},
year = {Wed Mar 20 00:00:00 EDT 2013},
month = {Wed Mar 20 00:00:00 EDT 2013}
}