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

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:
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Publication Date:
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
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 838; Journal Issue: 1; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
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 Orgs:
DES Collaboration
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: abundances; galaxies: dwarf; stars: abundances; stars: chemically peculiar
OSTI Identifier:
1349625
Alternate Identifier(s):
OSTI ID: 1360754; OSTI ID: 1362064

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., 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.. 2017. "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)},
number = 1,
volume = 838,
place = {United States},
year = {2017},
month = {3}
}