Atypical Mg-poor Milky Way Field Stars with Globular Cluster Second-generation-like Chemical Patterns
Por:
Fernandez-Trincado, J. G., Zamora, O., Garcia-Hernandez, D. A., Souto, Diogo, Dell'Agli, F., Schiavon, R. P., Geisler, D., Tang, B., Villanova, S., Hasselquist, Sten, Mennickent, R. E., Cunha, Katia, Shetrone, M., Allende Prieto, Carlos, Vieira, K., Zasowski, G., Sobeck, J., Hayes, C. R., Majewski, S. R., Placco, V. M., Beers, T. C., Schleicher, D. R. G., Robin, A. C., Meszaros, Sz, Masseron, T., Garcia Perez, Ana E., Anders, F., Meza, A., Alves-Brito, A., Carrera, R., Minniti, D., Lane, R. R., Fernandez-Alvar, E., Moreno, E., Pichardo, B., Perez-Villegas, A., Schultheis, M., Roman-Lopes, A., Fuentes, C. E., Nitschelm, C., Harding, P., Bizyaev, D., Pan, K., Oravetz, D., Simmons, A., Ivans, Inese I., Blanco-Cuaresma, S., Hernandez, J., Alonso-Garcia, J., Valenzuela, O., Chaname, J.
Publicada:
1 sep 2017
Resumen:
We report the peculiar chemical abundance patterns of 11 atypical Milky
Way (MW) field red giant stars observed by the Apache Point Observatory
Galactic Evolution Experiment (APOGEE). These atypical giants exhibit
strong Al and N enhancements accompanied by C and Mg depletions,
strikingly similar to those observed in the so-called second-generation
(SG) stars of globular clusters (GCs). Remarkably, we find low Mg
abundances ([Mg/Fe]. < 0.0) together with strong Al and N
overabundances in the majority (5/7) of the metal-rich ([Fe/H] greater
than or similar to-1.0) sample stars, which is at odds with actual
observations of SG stars in Galactic GCs of similar metallicities. This
chemical pattern is unique and unprecedented among MW stars, posing
urgent questions about its origin. These atypical stars could be former
SG stars of dissolved GCs formed with intrinsically lower abundances of
Mg and enriched Al (subsequently self-polluted by massive AGB stars) or
the result of exotic binary systems. We speculate that the stars
Mg-deficiency as well as the orbital properties suggest that they could
have an extragalactic origin. This discovery should guide future
dedicated spectroscopic searches of atypical stellar chemical patterns
in our Galaxy, a fundamental step forward to understanding the Galactic
formation and evolution.
Filiaciones:
Fernandez-Trincado, J. G.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Univ Bourgogne Franche Comte, Observ Besancon, OSU THETA Franche Comte, Inst Utinam,CNRS UMR 6213, BP 1615, F-25010 Besancon, France
Zamora, O.:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La La, Dept Astrofis, E-38206 Tenerife, Spain
Garcia-Hernandez, D. A.:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La La, Dept Astrofis, E-38206 Tenerife, Spain
Souto, Diogo:
Observ Nacl, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, RJ, Brazil
Dell'Agli, F.:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La La, Dept Astrofis, E-38206 Tenerife, Spain
Schiavon, R. P.:
Liverpool John Moores Univ, Astrophys Res Inst, 146 Brownlow Hill, Liverpool L3 5RF, Merseyside, England
Geisler, D.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Tang, B.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Villanova, S.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Hasselquist, Sten:
New Mexico State Univ, Las Cruces, NM 88003 USA
Mennickent, R. E.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Cunha, Katia:
Observ Nacl, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, RJ, Brazil
Univ Arizona, Steward Observ, 933 North Cherry Ave, Tucson, AZ 85721 USA
Shetrone, M.:
Univ Texas Austin, McDonald Observ, Ft Davis, TX 79734 USA
Allende Prieto, Carlos:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La La, Dept Astrofis, E-38206 Tenerife, Spain
Vieira, K.:
Ctr Invest Astron, AP 264, Merida 5101A, Venezuela
Zasowski, G.:
Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA
Univ Utah, Dept Phys & Astron, 115 S 1400 E, Salt Lake City, UT 84112 USA
Sobeck, J.:
Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA
Hayes, C. R.:
Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA
Majewski, S. R.:
Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA
Placco, V. M.:
Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA
Univ Notre Dame, JINA Ctr Evolut Elements, Notre Dame, IN 46556 USA
Beers, T. C.:
Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA
Univ Notre Dame, JINA Ctr Evolut Elements, Notre Dame, IN 46556 USA
Schleicher, D. R. G.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Robin, A. C.:
Univ Bourgogne Franche Comte, Observ Besancon, OSU THETA Franche Comte, Inst Utinam,CNRS UMR 6213, BP 1615, F-25010 Besancon, France
Meszaros, Sz:
ELTE Gothard Astrophys Observ, Szent Imre herceg St 112, H-9704 Szombathely, Hungary
Hungarian Acad Sci, Budapest, Hungary
Masseron, T.:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La La, Dept Astrofis, E-38206 Tenerife, Spain
Garcia Perez, Ana E.:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La La, Dept Astrofis, E-38206 Tenerife, Spain
Anders, F.:
Leibniz Inst Astrophys Potsdam AIP, Sternwarte 16, D-14482 Potsdam, Germany
LIneA, Lab Interinst E Astron, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, RJ, Brazil
Meza, A.:
Univ Andres Bello, Fac Ciencias Exactas, Dept Fis, Ave Fernandez Concha 700, Santiago, Chile
Alves-Brito, A.:
Univ Fed Rio Grande do Sul, Inst Fis, Ave Bento Goncalves 9500, Porto Alegre, RS, Brazil
Carrera, R.:
Inst Astrofis Canarias, E-38205 Tenerife, Spain
Univ La La, Dept Astrofis, E-38206 Tenerife, Spain
Minniti, D.:
Inst Milenio Astrofis, Santiago, Chile
Vatican Observ, V-00120 Vatican City, Vatican
Pontificia Univ Catolica Chile, Inst Astrofis, Ave Vicuna Mackenna 4860, Santiago 7820436, Chile
Lane, R. R.:
Pontificia Univ Catolica Chile, Inst Astrofis, Ave Vicuna Mackenna 4860, Santiago 7820436, Chile
Fernandez-Alvar, E.:
Univ Nacl Autonoma Mexico, Inst Astron, Apdo Postal 70264, Mexico City 04510, DF, Mexico
Moreno, E.:
Univ Nacl Autonoma Mexico, Inst Astron, Apdo Postal 70264, Mexico City 04510, DF, Mexico
Pichardo, B.:
Univ Nacl Autonoma Mexico, Inst Astron, Apdo Postal 70264, Mexico City 04510, DF, Mexico
Perez-Villegas, A.:
Max Planck Inst Extraterr Phys, Giessenbachstr, D-85748 Garching, Germany
Schultheis, M.:
Univ Cote dAzur, Lab Lagrange, Observ Cote dAzur, CNRS, Blvd Observ, F-06304 Nice, France
Roman-Lopes, A.:
Univ La Serena, Fac Ciencias, Dept Fis, Cisternas 1200, La Serena, Chile
Fuentes, C. E.:
Univ Concepcion, Dept Astron, Casilla 160-C, Concepcion, Chile
Nitschelm, C.:
Univ Antofagasta, Unidad Astron, Ave Angamos 601, Antofagasta 1270300, Chile
Harding, P.:
Case Western Reserve Univ, Dept Astron, Cleveland, OH 44106 USA
Bizyaev, D.:
Apache Point Observ, POB 59, Sunspot, NM 88349 USA
New Mexico State Univ, POB 59, Sunspot, NM 88349 USA
Moscow MV Lomonosov State Univ, Sternberg Astron Inst, Moscow, Russia
Pan, K.:
Univ Utah, Dept Phys & Astron, 115 S 1400 E, Salt Lake City, UT 84112 USA
Oravetz, D.:
Univ Utah, Dept Phys & Astron, 115 S 1400 E, Salt Lake City, UT 84112 USA
Simmons, A.:
Apache Point Observ, POB 59, Sunspot, NM 88349 USA
New Mexico State Univ, POB 59, Sunspot, NM 88349 USA
Ivans, Inese I.:
Univ Utah, Dept Phys & Astron, 115 S 1400 E, Salt Lake City, UT 84112 USA
Blanco-Cuaresma, S.:
Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA
Hernandez, J.:
Univ Nacl Autonoma Mexico, Inst Astron, Unidad Acad Ensenada, Ensenada 22860, Baja California, Mexico
Alonso-Garcia, J.:
Inst Milenio Astrofis, Santiago, Chile
Univ Antofagasta, Unidad Astron, Ave Angamos 601, Antofagasta 1270300, Chile
Valenzuela, O.:
Univ Nacl Autonoma Mexico, Inst Astron, Apdo Postal 70264, Mexico City 04510, DF, Mexico
Chaname, J.:
Inst Milenio Astrofis, Santiago, Chile
Pontificia Univ Catolica Chile, Inst Astrofis, Ave Vicuna Mackenna 4860, Santiago 7820436, Chile
|