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Title: MAPPING THE SHORES OF THE BROWN DWARF DESERT. III. YOUNG MOVING GROUPS

Abstract

We present the results of an aperture-masking interferometry survey for substellar companions around 67 members of the young ({approx}8-200 Myr) nearby ({approx}5-86 pc) AB Doradus, {beta} Pictoris, Hercules-Lyra, TW Hya, and Tucana-Horologium stellar associations. Observations were made at near-infrared wavelengths between 1.2 and 3.8 {mu}m using the adaptive optics facilities of the Keck II, Very Large Telescope UT4, and Palomar Hale Telescopes. Typical contrast ratios of {approx}100-200 were achieved at angular separations between {approx}40 and 320 mas, with our survey being 100% complete for companions with masses below {approx}0.25 M{sub Sun} across this range. We report the discovery of a 0.52 {+-} 0.09 M{sub Sun} companion to HIP 14807, as well as the detections and orbits of previously known stellar companions to HD 16760, HD 113449, and HD 160934. We show that the companion to HD 16760 is in a face-on orbit, resulting in an upward revision of its mass from M{sub 2}sin i {approx} 14 M{sub J} to M{sub 2} = 0.28 {+-} 0.04 M{sub Sun }. No substellar companions were detected around any of our sample members, despite our ability to detect companions with masses below 80 M{sub J} for 50 of our targets: of these, our sensitivitymore » extended down to 40 M{sub J} around 30 targets, with a subset of 22 subject to the still more stringent limit of 20 M{sub J}. A statistical analysis of our non-detection of substellar companions allows us to place constraints on their frequency around {approx}0.2-1.5 M{sub Sun} stars. In particular, considering companion mass distributions that have been proposed in the literature, we obtain an upper limit estimate of {approx}9%-11% for the frequency of 20-80 M{sub J} companions between 3 and 30 AU at 95% confidence, assuming that their semimajor axes are distributed according to dN/da{proportional_to}a{sup -1} in this range.« less

Authors:
; ; ; ;  [1];  [2];  [3];
  1. Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia)
  2. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
  3. National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States)
Publication Date:
OSTI Identifier:
22004276
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 744; Journal Issue: 2; Other Information: 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; DWARF STARS; INTERFEROMETRY; MASS DISTRIBUTION; ORBITS; TELESCOPES

Citation Formats

Evans, T M, Ireland, M J, Stewart, P, Tuthill, P G, Lacour, S, Kraus, A L, Martinache, F, Carpenter, J M, and Hillenbrand, L. A., E-mail: tom.evans@astro.ox.ac.uk. MAPPING THE SHORES OF THE BROWN DWARF DESERT. III. YOUNG MOVING GROUPS. United States: N. p., 2012. Web. doi:10.1088/0004-637X/744/2/120.
Evans, T M, Ireland, M J, Stewart, P, Tuthill, P G, Lacour, S, Kraus, A L, Martinache, F, Carpenter, J M, & Hillenbrand, L. A., E-mail: tom.evans@astro.ox.ac.uk. MAPPING THE SHORES OF THE BROWN DWARF DESERT. III. YOUNG MOVING GROUPS. United States. https://doi.org/10.1088/0004-637X/744/2/120
Evans, T M, Ireland, M J, Stewart, P, Tuthill, P G, Lacour, S, Kraus, A L, Martinache, F, Carpenter, J M, and Hillenbrand, L. A., E-mail: tom.evans@astro.ox.ac.uk. 2012. "MAPPING THE SHORES OF THE BROWN DWARF DESERT. III. YOUNG MOVING GROUPS". United States. https://doi.org/10.1088/0004-637X/744/2/120.
@article{osti_22004276,
title = {MAPPING THE SHORES OF THE BROWN DWARF DESERT. III. YOUNG MOVING GROUPS},
author = {Evans, T M and Ireland, M J and Stewart, P and Tuthill, P G and Lacour, S and Kraus, A L and Martinache, F and Carpenter, J M and Hillenbrand, L. A., E-mail: tom.evans@astro.ox.ac.uk},
abstractNote = {We present the results of an aperture-masking interferometry survey for substellar companions around 67 members of the young ({approx}8-200 Myr) nearby ({approx}5-86 pc) AB Doradus, {beta} Pictoris, Hercules-Lyra, TW Hya, and Tucana-Horologium stellar associations. Observations were made at near-infrared wavelengths between 1.2 and 3.8 {mu}m using the adaptive optics facilities of the Keck II, Very Large Telescope UT4, and Palomar Hale Telescopes. Typical contrast ratios of {approx}100-200 were achieved at angular separations between {approx}40 and 320 mas, with our survey being 100% complete for companions with masses below {approx}0.25 M{sub Sun} across this range. We report the discovery of a 0.52 {+-} 0.09 M{sub Sun} companion to HIP 14807, as well as the detections and orbits of previously known stellar companions to HD 16760, HD 113449, and HD 160934. We show that the companion to HD 16760 is in a face-on orbit, resulting in an upward revision of its mass from M{sub 2}sin i {approx} 14 M{sub J} to M{sub 2} = 0.28 {+-} 0.04 M{sub Sun }. No substellar companions were detected around any of our sample members, despite our ability to detect companions with masses below 80 M{sub J} for 50 of our targets: of these, our sensitivity extended down to 40 M{sub J} around 30 targets, with a subset of 22 subject to the still more stringent limit of 20 M{sub J}. A statistical analysis of our non-detection of substellar companions allows us to place constraints on their frequency around {approx}0.2-1.5 M{sub Sun} stars. In particular, considering companion mass distributions that have been proposed in the literature, we obtain an upper limit estimate of {approx}9%-11% for the frequency of 20-80 M{sub J} companions between 3 and 30 AU at 95% confidence, assuming that their semimajor axes are distributed according to dN/da{proportional_to}a{sup -1} in this range.},
doi = {10.1088/0004-637X/744/2/120},
url = {https://www.osti.gov/biblio/22004276}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 744,
place = {United States},
year = {Tue Jan 10 00:00:00 EST 2012},
month = {Tue Jan 10 00:00:00 EST 2012}
}