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Title: The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample

Abstract

We present 114 trigonometric parallaxes for 107 nearby white dwarf (WD) systems from both the Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI) and the U. S. Naval Observatory Flagstaff Station (NOFS) parallax programs. Of these, 76 parallaxes for 69 systems were measured by the CTIOPI program and 38 parallaxes for as many systems were measured by the NOFS program. A total of 50 systems are confirmed to be within the 25-pc horizon of interest. Coupled with a spectroscopic confirmation of a common proper-motion companion to a Hipparcos star within 25 pc as well as confirmation parallax determinations for two WD systems included in the recently released Tycho Gaia Astrometric Solution catalog, we add 53 new systems to the 25-pc WD sample—a 42% increase. Our sample presented here includes four strong candidate halo systems, a new metal-rich DAZ WD, a confirmation of a recently discovered nearby short-period ( P  = 2.85 hr) double degenerate, a WD with a new astrometric perturbation (long period, unconstrained with our data), and a new triple system where the WD companion main-sequence star has an astrometric perturbation ( P  ∼ 1.6 year).

Authors:
; ;  [1]; ;  [2]; ;  [3]; ;  [4];  [5];  [6];  [7]
  1. U.S. Naval Observatory, 10391 West Naval Observatory Road, Flagstaff, AZ 86005-8521 (United States)
  2. Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302-4106 (United States)
  3. RECONS Institute, Chambersburg, PA 17201 (United States)
  4. Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec H3C 3J7 (Canada)
  5. University of North Carolina at Chapel Hill, Dept. of Physics and Astronomy, Chapel Hill, NC 27599 (United States)
  6. Department of Physics, High Point University, One University Parkway, High Point, NC 27268 (United States)
  7. Gemini Observatory, Southern Operations Center, Casilla 603, La Serena (Chile)
Publication Date:
OSTI Identifier:
22663128
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 154; 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; CATALOGS; DISTANCE; DISTURBANCES; GALAXIES; MAIN SEQUENCE STARS; METALS; PROPER MOTION; STAR EVOLUTION; WHITE DWARF STARS

Citation Formats

Subasavage, John P., Harris, Hugh C., Dahn, Conard C., Jao, Wei-Chun, Lépine, Sébastien, Henry, Todd J., Ianna, Philip A., Bergeron, P., Dufour, P., Dunlap, Bart H., Barlow, Brad N., and Margheim, Steven J., E-mail: jsubasavage@nofs.navy.mil. The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample. United States: N. p., 2017. Web. doi:10.3847/1538-3881/AA76E0.
Subasavage, John P., Harris, Hugh C., Dahn, Conard C., Jao, Wei-Chun, Lépine, Sébastien, Henry, Todd J., Ianna, Philip A., Bergeron, P., Dufour, P., Dunlap, Bart H., Barlow, Brad N., & Margheim, Steven J., E-mail: jsubasavage@nofs.navy.mil. The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample. United States. doi:10.3847/1538-3881/AA76E0.
Subasavage, John P., Harris, Hugh C., Dahn, Conard C., Jao, Wei-Chun, Lépine, Sébastien, Henry, Todd J., Ianna, Philip A., Bergeron, P., Dufour, P., Dunlap, Bart H., Barlow, Brad N., and Margheim, Steven J., E-mail: jsubasavage@nofs.navy.mil. Sat . "The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample". United States. doi:10.3847/1538-3881/AA76E0.
@article{osti_22663128,
title = {The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample},
author = {Subasavage, John P. and Harris, Hugh C. and Dahn, Conard C. and Jao, Wei-Chun and Lépine, Sébastien and Henry, Todd J. and Ianna, Philip A. and Bergeron, P. and Dufour, P. and Dunlap, Bart H. and Barlow, Brad N. and Margheim, Steven J., E-mail: jsubasavage@nofs.navy.mil},
abstractNote = {We present 114 trigonometric parallaxes for 107 nearby white dwarf (WD) systems from both the Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI) and the U. S. Naval Observatory Flagstaff Station (NOFS) parallax programs. Of these, 76 parallaxes for 69 systems were measured by the CTIOPI program and 38 parallaxes for as many systems were measured by the NOFS program. A total of 50 systems are confirmed to be within the 25-pc horizon of interest. Coupled with a spectroscopic confirmation of a common proper-motion companion to a Hipparcos star within 25 pc as well as confirmation parallax determinations for two WD systems included in the recently released Tycho Gaia Astrometric Solution catalog, we add 53 new systems to the 25-pc WD sample—a 42% increase. Our sample presented here includes four strong candidate halo systems, a new metal-rich DAZ WD, a confirmation of a recently discovered nearby short-period ( P  = 2.85 hr) double degenerate, a WD with a new astrometric perturbation (long period, unconstrained with our data), and a new triple system where the WD companion main-sequence star has an astrometric perturbation ( P  ∼ 1.6 year).},
doi = {10.3847/1538-3881/AA76E0},
journal = {Astronomical Journal (Online)},
number = 1,
volume = 154,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}
  • We present accurate trigonometric parallaxes for 20 new members of the 25 pc white dwarf (WD) sample as part of the Discovery and Evalution of Nearby Stellar Embers (DENSE) project.{sup 7} http://www.DenseProject.com Previously, there were a total of 112 WD systems with trigonometric parallaxes placing them within 25 pc and of these, 99 have trigonometric parallaxes known to better than 10%. Thus, the 20 new members presented in this work represent a 20% increase in the number of WDs accurately known to be within 25 pc. In addition, we present updated parallaxes for seven known WDs within 10 pc thatmore » have been observed as part of the Astrometric Search for Planets Encircling Nearby Stars initiative to monitor nearby southern red dwarfs and WDs for astrometric perturbations from unseen companions. Including a few WD companions and WDs beyond 25 pc, we present a total of 33 trigonometric parallaxes. We perform atmospheric modeling for WDs to determine physical parameters (i.e., T {sub eff}, log g, mass, and WD age). Finally, a new ZZ Ceti pulsating WD was identified and revised constraints are placed on two mixed H/He atmosphere cool WDs that display continuum absorption in the near-infrared.« less
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  • As a step toward completing and characterizing the census of the solar neighborhood, we present astrometric, photometric, and spectroscopic observations of 32 systems observed with the Cerro Tololo Inter-American Observatory 0.9 m and 1.5 m telescopes. Astrometry from the 0.9 m indicates that among the 17 systems that had no previous published trigonometric parallaxes, 14 are within 25 pc. In the full sample, nine systems have proper motions larger than 0.″5 yr{sup −1}, including 2MASS J02511490-0352459, which exceeds 2.″0 yr{sup −1}. VRI photometry from the 0.9 m and optical spectra from the 1.5 m indicate that the targets have Vmore »  = 11–22 mag and spectral types M3.0V–L3.0V. For 2MASS J23062928-0502285 (TRAPPIST-1), we present updated astrometry and photometric variability based on over 12 years of observations. Of the nine binaries in the sample, two promise mass determinations in the next decade: LHS 6167AB, an M4.5V system for which we present an accurate parallax placing the binary at 9.7 pc, and 2MASS J23515048-2537367AB, an M8.5V system at 21.1 pc for which we present the first evidence of an unseen, low-mass companion. Most importantly, Na i and K i gravity indicators, H α measurements, long-term photometric variability, locations on the H-R diagram, and kinematic assessments indicate that as many as 13 of the systems are young, including candidate members of young moving groups, with ages less than ∼120 Myr.« less
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