skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: An r-process enhanced star in the dwarf galaxy Tucana III

Abstract

Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate Tucana III. Because it is particularly bright for a star in an ultra-faint Milky Way (MW) satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66–593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the r-process and can be classified as an r-I star. DES J235532 is the first r-I star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain r-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with r-I and r-II stars found in other dwarf galaxies and in the MW halo suggests a common astrophysical origin for the neutron-capture elements seen in all r-process enhanced stars. Furthermore, we explore both internal and external scenarios for the r-process enrichment of Tuc III and show that with abundance patterns for additional stars, it should be possible to distinguish between them.

Authors:
ORCiD logo; ; ORCiD logo; ; ORCiD logo; ; ; ; ; ; ; ORCiD logo; ; ; ; ; ORCiD logo; ; ; more »; ; ; ; ; ; ; ; ; ORCiD logo; ; ORCiD logo; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ORCiD logo; ; ; ; ORCiD logo; ORCiD logo « less
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
DES Collaboration
OSTI Identifier:
1349625
Alternate Identifier(s):
OSTI ID: 1360754; OSTI ID: 1362064
Report Number(s):
arXiv:1702.07430; FERMILAB-PUB-17-189-AE
Journal ID: ISSN 1538-4357; KJ0402000; KJ0503000; ERKJ311; ERKJEPM; TRN: US1700595
Grant/Contract Number:  
AC05-00OR22725; AC02-76SF00515; AC02-07CH11359
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Volume: 838; Journal Issue: 1; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: abundances; galaxies: dwarf; stars: abundances; stars: chemically peculiar

Citation Formats

Hansen, T. T., Simon, J. D., Marshall, J. L., Li, T. S., Carollo, D., DePoy, D. L., Nagasawa, D. Q., Bernstein, R. A., Drlica-Wagner, A., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Lévy, A., Brooks, D., Buckley-Geer, E., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., Costa, L. N. da, Desai, S., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., James, D. J., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Miquel, R., Plazas, A. A., Romer, A. K., Sanchez, E., Santiago, B., Scarpine, V., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., and Walker, A. R. An r-process enhanced star in the dwarf galaxy Tucana III. United States: N. p., 2017. Web. doi:10.3847/1538-4357/aa634a.
Hansen, T. T., Simon, J. D., Marshall, J. L., Li, T. S., Carollo, D., DePoy, D. L., Nagasawa, D. Q., Bernstein, R. A., Drlica-Wagner, A., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Lévy, A., Brooks, D., Buckley-Geer, E., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., Costa, L. N. da, Desai, S., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., James, D. J., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Miquel, R., Plazas, A. A., Romer, A. K., Sanchez, E., Santiago, B., Scarpine, V., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., & Walker, A. R. An r-process enhanced star in the dwarf galaxy Tucana III. United States. doi:10.3847/1538-4357/aa634a.
Hansen, T. T., Simon, J. D., Marshall, J. L., Li, T. S., Carollo, D., DePoy, D. L., Nagasawa, D. Q., Bernstein, R. A., Drlica-Wagner, A., Abdalla, F. B., Allam, S., Annis, J., Bechtol, K., Benoit-Lévy, A., Brooks, D., Buckley-Geer, E., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Cunha, C. E., Costa, L. N. da, Desai, S., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., García-Bellido, J., Gaztanaga, E., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., James, D. J., Krause, E., Kuehn, K., Kuropatkin, N., Lahav, O., Miquel, R., Plazas, A. A., Romer, A. K., Sanchez, E., Santiago, B., Scarpine, V., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., and Walker, A. R. Mon . "An r-process enhanced star in the dwarf galaxy Tucana III". United States. doi:10.3847/1538-4357/aa634a. https://www.osti.gov/servlets/purl/1349625.
@article{osti_1349625,
title = {An r-process enhanced star in the dwarf galaxy Tucana III},
author = {Hansen, T. T. and Simon, J. D. and Marshall, J. L. and Li, T. S. and Carollo, D. and DePoy, D. L. and Nagasawa, D. Q. and Bernstein, R. A. and Drlica-Wagner, A. and Abdalla, F. B. and Allam, S. and Annis, J. and Bechtol, K. and Benoit-Lévy, A. and Brooks, D. and Buckley-Geer, E. and Rosell, A. Carnero and Kind, M. Carrasco and Carretero, J. and Cunha, C. E. and Costa, L. N. da and Desai, S. and Eifler, T. F. and Neto, A. Fausti and Flaugher, B. and Frieman, J. and García-Bellido, J. and Gaztanaga, E. and Gerdes, D. W. and Gruen, D. and Gruendl, R. A. and Gschwend, J. and Gutierrez, G. and James, D. J. and Krause, E. and Kuehn, K. and Kuropatkin, N. and Lahav, O. and Miquel, R. and Plazas, A. A. and Romer, A. K. and Sanchez, E. and Santiago, B. and Scarpine, V. and Smith, R. C. and Soares-Santos, M. and Sobreira, F. and Suchyta, E. and Swanson, M. E. C. and Tarle, G. and Walker, A. R.},
abstractNote = {Chemically peculiar stars in dwarf galaxies provide a window for exploring the birth environment of stars with varying chemical enrichment. We present a chemical abundance analysis of the brightest star in the newly discovered ultra-faint dwarf galaxy candidate Tucana III. Because it is particularly bright for a star in an ultra-faint Milky Way (MW) satellite, we are able to measure the abundance of 28 elements, including 13 neutron-capture species. This star, DES J235532.66–593114.9 (DES J235532), shows a mild enhancement in neutron-capture elements associated with the r-process and can be classified as an r-I star. DES J235532 is the first r-I star to be discovered in an ultra-faint satellite, and Tuc III is the second extremely low-luminosity system found to contain r-process enriched material, after Reticulum II. Comparison of the abundance pattern of DES J235532 with r-I and r-II stars found in other dwarf galaxies and in the MW halo suggests a common astrophysical origin for the neutron-capture elements seen in all r-process enhanced stars. Furthermore, we explore both internal and external scenarios for the r-process enrichment of Tuc III and show that with abundance patterns for additional stars, it should be possible to distinguish between them.},
doi = {10.3847/1538-4357/aa634a},
journal = {The Astrophysical Journal (Online)},
issn = {1538-4357},
number = 1,
volume = 838,
place = {United States},
year = {2017},
month = {3}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 10 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Carbon‐enhanced Metal‐poor Stars. I. Chemical Compositions of 26 Stars
journal, January 2007

  • Aoki, Wako; Beers, Timothy C.; Christlieb, Norbert
  • The Astrophysical Journal, Vol. 655, Issue 1
  • DOI: 10.1086/509817

Nucleosynthesis-relevant conditions in neutrino-driven supernova outflows: I. Spherically symmetric hydrodynamic simulations
journal, March 2007


Neutrino-driven wind simulations and nucleosynthesis of heavy elements
journal, November 2012


The Chemical Composition of the Sun
journal, September 2009


The Hamburg/ESO R-process enhanced star survey (HERES): II. Spectroscopic analysis of the survey sample
journal, July 2005


Systematics of Dynamical mass Ejection, Nucleosynthesis, and Radioactively Powered Electromagnetic Signals from Neutron-Star Mergers
journal, July 2013


Eight new Milky way Companions Discovered in First-Year dark Energy Survey data
journal, June 2015


The Discovery and Analysis of Very Metal-Poor Stars in the Galaxy
journal, September 2005


MIKE: A Double Echelle Spectrograph for the Magellan Telescopes at Las Campanas Observatory
conference, March 2003

  • Bernstein, Rebecca; Shectman, Stephen A.; Gunnels, Steven M.
  • Astronomical Telescopes and Instrumentation, SPIE Proceedings
  • DOI: 10.1117/12.461502

parsec : stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
journal, October 2012


Some Nucleosynthesis Effects Associated with r ‐Process Jets
journal, April 2003

  • Cameron, A. G. W.
  • The Astrophysical Journal, Vol. 587, Issue 1
  • DOI: 10.1086/368110

Spectroscopic Binaries, Velocity Jitter, and Rotation in Field Metal-poor Red Giant and Red Horizontal-Branch Stars
journal, January 2003

  • Carney, Bruce W.; Latham, David W.; Stefanik, Robert P.
  • The Astronomical Journal, Vol. 125, Issue 1
  • DOI: 10.1086/345386

The Chemical Evolution of the Draco Dwarf Spheroidal Galaxy
journal, July 2009


The Chemical Evolution of the ursa Minor Dwarf Spheroidal Galaxy
journal, July 2010


The Dartmouth Stellar Evolution Database
journal, September 2008

  • Dotter, Aaron; Chaboyer, Brian; Jevremović, Darko
  • The Astrophysical Journal Supplement Series, Vol. 178, Issue 1
  • DOI: 10.1086/589654

Eight Ultra-Faint Galaxy Candidates Discovered in year two of the dark Energy Survey
journal, November 2015


The dark Energy Camera
journal, October 2015


Abundance ratios of red giants in low-mass ultra-faint dwarf spheroidal galaxies
journal, March 2016


Deriving Stellar Effective Temperatures of Metal-Poor Stars with the Excitation Potential Method
journal, May 2013

  • Frebel, Anna; Casey, Andrew R.; Jacobson, Heather R.
  • The Astrophysical Journal, Vol. 769, Issue 1
  • DOI: 10.1088/0004-637X/769/1/57

[CLC][ITAL]r[/ITAL][/CLC]-Process in Neutron Star Mergers
journal, November 1999

  • Freiburghaus, C.; Rosswog, S.; Thielemann, F. -K.
  • The Astrophysical Journal, Vol. 525, Issue 2
  • DOI: 10.1086/312343

Nucleosynthesis in Magnetically Driven Jets from Collapsars
journal, June 2008

  • Fujimoto, Shin‐ichiro; Nishimura, Nobuya; Hashimoto, Masa‐aki
  • The Astrophysical Journal, Vol. 680, Issue 2
  • DOI: 10.1086/529416

Draco 119: A Remarkable Heavy‐Element–deficient Giant
journal, September 2004

  • Fulbright, Jon. P.; Rich, R. Michael; Castro, Sandra
  • The Astrophysical Journal, Vol. 612, Issue 1
  • DOI: 10.1086/421712

"Sculptor-ing" the Galaxy? The Chemical Compositions of Red Giants in the Sculptor Dwarf Spheroidal Galaxy
journal, March 2005

  • Geisler, Doug; Smith, Verne V.; Wallerstein, George
  • The Astronomical Journal, Vol. 129, Issue 3
  • DOI: 10.1086/427540

r -PROCESS NUCLEOSYNTHESIS IN DYNAMICALLY EJECTED MATTER OF NEUTRON STAR MERGERS
journal, August 2011

  • Goriely, Stephane; Bauswein, Andreas; Janka, Hans-Thomas
  • The Astrophysical Journal, Vol. 738, Issue 2
  • DOI: 10.1088/2041-8205/738/2/L32

Abundance Variations within Globular Clusters
journal, September 2004


The role of binaries in the enrichment of the early Galactic halo: I. r -process-enhanced metal-poor stars
journal, October 2015


THE BINARY FREQUENCY OF r -PROCESS-ELEMENT-ENHANCED METAL-POOR STARS AND ITS IMPLICATIONS: CHEMICAL TAGGING IN THE PRIMITIVE HALO OF THE MILKY WAY
journal, November 2011

  • Hansen, Terese; Andersen, Johannes; Nordström, Birgitta
  • The Astrophysical Journal, Vol. 743, Issue 1
  • DOI: 10.1088/2041-8205/743/1/L1

First stars. I. The extreme r -element rich, iron-poor halo giant CS 31082-001 : Implications for the
journal, May 2002


The early days of the Sculptor dwarf spheroidal galaxy
journal, October 2015


R-process enrichment from a single event in an ancient dwarf galaxy
journal, March 2016

  • Ji, Alexander P.; Frebel, Anna; Chiti, Anirudh
  • Nature, Vol. 531, Issue 7596
  • DOI: 10.1038/nature17425

COMPLETE ELEMENT ABUNDANCES OF NINE STARS IN THE r -PROCESS GALAXY RETICULUM II
journal, October 2016


Chemical Abundance Analysis of a Neutron-Capture Enhanced red Giant in the Bulge Plaut Field
journal, September 2013

  • Johnson, Christian I.; McWilliam, Andrew; Rich, R. Michael
  • The Astrophysical Journal, Vol. 775, Issue 1
  • DOI: 10.1088/2041-8205/775/1/L27

Optimal Techniques in Two‐dimensional Spectroscopy: Background Subtraction for the 21st Century
journal, June 2003

  • Kelson, Daniel D.
  • Publications of the Astronomical Society of the Pacific, Vol. 115, Issue 808
  • DOI: 10.1086/375502

Detailed Abundances of two very Metal-Poor Stars in Dwarf Galaxies
journal, November 2012


CONTRIBUTION OF NEUTRON STAR MERGERS TO THE r-PROCESS CHEMICAL EVOLUTION IN THE HIERARCHICAL GALAXY FORMATION
journal, October 2016


Beasts of the Southern Wild: Discovery of nine Ultra Faint Satellites in the Vicinity of the Magellanic Clouds
journal, May 2015

  • Koposov, Sergey E.; Belokurov, Vasily; Torrealba, Gabriel
  • The Astrophysical Journal, Vol. 805, Issue 2
  • DOI: 10.1088/0004-637X/805/2/130

On the astrophysical robustness of the neutron star merger r-process: Robust r-process in neutron star mergers
journal, October 2012


Black-hole-neutron-star collisions
journal, September 1974

  • Lattimer, J. M.; Schramm, D. N.
  • The Astrophysical Journal, Vol. 192
  • DOI: 10.1086/181612

VLT/FLAMES spectroscopy of red giant branch stars in the Fornax dwarf spheroidal galaxy
journal, December 2014


A high-resolution VLT/FLAMES study of individual stars in the centre of the Fornax dwarf spheroidal galaxy
journal, November 2010


CH in stellar atmospheres: an extensive linelist
journal, November 2014


Spectroscopic Analysis of 33 of the Most Metal Poor Stars. II.
journal, June 1995

  • McWilliam, Andrew; Preston, George W.; Sneden, Christopher
  • The Astronomical Journal, Vol. 109
  • DOI: 10.1086/117486

CHEMISTRY OF THE SAGITTARIUS DWARF GALAXY: A TOP-LIGHT INITIAL MASS FUNCTION, OUTFLOWS, AND THE R -PROCESS
journal, November 2013


Electromagnetic counterparts of compact object mergers powered by the radioactive decay of r-process nuclei: Transients from compact object mergers
journal, June 2010


Decompression of initially cold neutron star matter - A mechanism for the r-process?
journal, August 1989

  • Meyer, Bradley S.
  • The Astrophysical Journal, Vol. 343
  • DOI: 10.1086/167702

The Tidal Evolution of Local Group Dwarf Spheroidals
journal, January 2008

  • Penarrubia, Jorge; Navarro, Julio F.; McConnachie, Alan W.
  • The Astrophysical Journal, Vol. 673, Issue 1
  • DOI: 10.1086/523686

Carbon-Enhanced Metal-Poor star Frequencies in the Galaxy: Corrections for the Effect of Evolutionary Status on Carbon Abundances
journal, November 2014

  • Placco, Vinicius M.; Frebel, Anna; Beers, Timothy C.
  • The Astrophysical Journal, Vol. 797, Issue 1
  • DOI: 10.1088/0004-637X/797/1/21

Abundances in the Uranium-rich Star CS 31082-001
journal, May 2001

  • Qian, Y. -Z.; Wasserburg, G. J.
  • The Astrophysical Journal, Vol. 552, Issue 1
  • DOI: 10.1086/320266

Oxygen Abundances in Nearby fgk Stars and the Galactic Chemical Evolution of the Local disk and halo
journal, January 2013


Nine new metal-poor stars on the subgiant and red horizontal branches with high levels of r-process enhancement★
journal, October 2014

  • Roederer, Ian U.; Cowan, John J.; Preston, George W.
  • Monthly Notices of the Royal Astronomical Society, Vol. 445, Issue 3
  • DOI: 10.1093/mnras/stu1977

CHARACTERIZING THE HEAVY ELEMENTS IN GLOBULAR CLUSTER M22 AND AN EMPIRICAL s -PROCESS ABUNDANCE DISTRIBUTION DERIVED FROM THE TWO STELLAR GROUPS
journal, November 2011


DETAILED CHEMICAL ABUNDANCES IN THE r -PROCESS-RICH ULTRA-FAINT DWARF GALAXY RETICULUM 2
journal, February 2016


A Search for Stars of very low Metal Abundance. vi. Detailed Abundances of 313 Metal-Poor Stars
journal, May 2014


The long-term evolution of neutron star merger remnants - I. The impact of r-process nucleosynthesis
journal, January 2014

  • Rosswog, S.; Korobkin, O.; Arcones, A.
  • Monthly Notices of the Royal Astronomical Society, Vol. 439, Issue 1
  • DOI: 10.1093/mnras/stt2502

Subaru/HDS Abundances in Three Giant Stars in the Ursa Minor Dwarf Spheroidal Galaxy
journal, December 2004

  • Sadakane, Kozo; Arimoto, Nobuo; Ikuta, Chisato
  • Publications of the Astronomical Society of Japan, Vol. 56, Issue 6
  • DOI: 10.1093/pasj/56.6.1041

Abundance Patterns in the Draco, Sextans, and Ursa Minor Dwarf Spheroidal Galaxies
journal, February 2001

  • Shetrone, Matthew D.; Cote, Patrick; Sargent, W. L. W.
  • The Astrophysical Journal, Vol. 548, Issue 2
  • DOI: 10.1086/319022

VLT/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies. I. Nucleosynthesis and Abundance Ratios
journal, February 2003

  • Shetrone, Matthew; Venn, Kim A.; Tolstoy, Eline
  • The Astronomical Journal, Vol. 125, Issue 2
  • DOI: 10.1086/345966

The Rise of the s ‐Process in the Galaxy
journal, December 2004

  • Simmerer, Jennifer; Sneden, Christopher; Cowan, John J.
  • The Astrophysical Journal, Vol. 617, Issue 2
  • DOI: 10.1086/424504

Chemical Signatures of the First Supernovae in the Sculptor Dwarf Spheroidal Galaxy
journal, March 2015

  • Simon, Joshua D.; Jacobson, Heather R.; Frebel, Anna
  • The Astrophysical Journal, Vol. 802, Issue 2
  • DOI: 10.1088/0004-637X/802/2/93

High-resolution abundance analysis of very metal-poor r-I stars
journal, May 2014


First stars: XVI. HST/STIS abundances of heavy elements in the uranium-rich metal-poor star CS 31082-001⋆⋆⋆
journal, February 2013


The first carbon-enhanced metal-poor star found in the Sculptor dwarf spheroidal
journal, February 2015


The nitrogen abundance of the very metal-poor star HD 122563.
journal, September 1973


Neutron-Capture Elements in the Early Galaxy
journal, September 2008


The Extremely Metal‐poor, Neutron Capture–rich Star CS 22892‐052: A Comprehensive Abundance Analysis
journal, July 2003

  • Sneden, Christopher; Cowan, John J.; Lawler, James E.
  • The Astrophysical Journal, Vol. 591, Issue 2
  • DOI: 10.1086/375491

The Abundances of Neutron-Capture Species in the very Metal-Poor Globular Cluster m15: a Uniform Analysis of red Giant Branch and red Horizontal Branch Stars
journal, April 2011

  • Sobeck, Jennifer S.; Kraft, Robert P.; Sneden, Christopher
  • The Astronomical Journal, Vol. 141, Issue 6
  • DOI: 10.1088/0004-6256/141/6/175

Extremely metal-poor stars in classical dwarf spheroidal galaxies: Fornax, Sculptor, and Sextans
journal, November 2010


Chemical feature of Eu abundance in the Draco dwarf spheroidal galaxy
journal, June 2015

  • Tsujimoto, Takuji; Ishigaki, Miho N.; Shigeyama, Toshikazu
  • Publications of the Astronomical Society of Japan, Vol. 67, Issue 3
  • DOI: 10.1093/pasj/psv035

Enrichment history of r-process elements shaped by a merger of neutron star pairs
journal, May 2014


Nucleosynthesis and the Inhomogeneous Chemical Evolution of the Carina Dwarf Galaxy
journal, May 2012


PRODUCTION OF ALL THE r -PROCESS NUCLIDES IN THE DYNAMICAL EJECTA OF NEUTRON STAR MERGERS
journal, June 2014


MAGNETOROTATIONALLY DRIVEN SUPERNOVAE AS THE ORIGIN OF EARLY GALAXY r -PROCESS ELEMENTS?
journal, April 2012


High precision differential abundance measurements in globular clusters: chemical inhomogeneities in NGC 6752★
journal, August 2013

  • Yong, David; Meléndez, Jorge; Grundahl, Frank
  • Monthly Notices of the Royal Astronomical Society, Vol. 434, Issue 4
  • DOI: 10.1093/mnras/stt1276

    Works referencing / citing this record:

    Evidence for the accretion origin of halo stars with an extreme r-process enhancement
    journal, April 2019


    The R -Process Alliance: A Comprehensive Abundance Analysis of HD 222925, a Metal-poor Star with an Extreme R -process Enhancement of [Eu/H] = −0.14
    journal, October 2018

    • Roederer, Ian U.; Sakari, Charli M.; Placco, Vinicius M.
    • The Astrophysical Journal, Vol. 865, Issue 2
    • DOI: 10.3847/1538-4357/aadd92

    Evidence for the accretion origin of halo stars with an extreme r-process enhancement
    journal, April 2019


    GW170817 --the first observed neutron star merger and its kilonova: Implications for the astrophysical site of the r-process
    journal, November 2019


    The R -Process Alliance: A Comprehensive Abundance Analysis of HD 222925, a Metal-poor Star with an Extreme R -process Enhancement of [Eu/H] = −0.14
    journal, October 2018

    • Roederer, Ian U.; Sakari, Charli M.; Placco, Vinicius M.
    • The Astrophysical Journal, Vol. 865, Issue 2
    • DOI: 10.3847/1538-4357/aadd92