The McDonald Observatory search for pulsating sdA stars : asteroseismic support for multiple populations

Autor: Bell, Keaton, Pelisoli, Ingrid Domingos, Kepler, Souza Oliveira, Brown, Warren R., Winget, Donald Earl, Winget, K. I., Vanderbosch, Zachary, Castanheira, Bárbara Garcia, Hermes, James J., Montgomery, Michael Houston, Koester, Detlev

Publikováno v: Repositório Institucional da UFRGS
Universidade Federal do Rio Grande do Sul (UFRGS)
instacron:UFRGS

Context. The nature of the recently identified “sdA” spectroscopic class of stars is not well understood. The thousands of known sdAs have H-dominated spectra, spectroscopic surface gravity values between main sequence stars and isolated white dw

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=od______3056::0f488409d466b6b158228576388f8384

Magnetic white dwarf stars in the Sloan Digital Sky Survey

Autor: Kepler, Souza Oliveira, Pelisoli, Ingrid Domingos, Jordan, Stefan, Kleinman, Scot James, Koester, Detlev, Kulebi, Baybars, Antonio, Viviane Peçanha, Castanheira, Bárbara Garcia, Nitta, Atsuko, Costa, Jose Eduardo da Silveira, Winget, Donald Earl, Kanaan Neto, Antonio Nemer, Fraga, Luciano

Publikováno v: Repositório Institucional da UFRGS
Universidade Federal do Rio Grande do Sul (UFRGS)
instacron:UFRGS

To obtain better statistics on the occurrence of magnetism among white dwarfs, we searched the spectra of the hydrogen atmosphere white dwarf stars (DAs) in the Data Release 7 of the Sloan Digital Sky Survey (SDSS) for Zeeman splittings and estimated

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=od______3056::ee63ae69d1ae8ac7126435d2dfa75130

Discovery of an ultramassive pulsating white dwarf

Autor: Hermes, James J., Kepler, Souza Oliveira, Castanheira, Bárbara Garcia, Gianninas, Alexandros, Winget, Donald Earl, Montgomery, Michael Houston, Brown, Warren R., Harrold, Samuel T.

Publikováno v: Repositório Institucional da UFRGS
Universidade Federal do Rio Grande do Sul (UFRGS)
instacron:UFRGS

We announce the discovery of themostmassive pulsating hydrogen-atmosphere white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the optical spectrum of this star show it is a 12,030 ± 210 K WD with a log g = 9.08 ± 0.06, which correspo

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=od______3056::261d11302da7b18dcfe248d92d79a579

The pulsations of PG 1351+489

Autor: Redaelli, Maurício, Kepler, Souza Oliveira, Costa, Jose Eduardo da Silveira, Winget, Donald Earl, Handler, Gerald, Castanheira, Bárbara Garcia, Kanaan Neto, Antonio Nemer, Fraga, Luciano, Henrique, P., Giovannini Junior, Odilon, Provencal, Judith L., Shipman, Harry L., Dalessio, J., Thompson, S. E., Mullally, Fergal, Brewer, M. M., Childers, D., Oksala, M. E., Rosen, Rachel, Wood, Matthew A., Reed, M. D., Walter, B., Strickland, Willie, Chandler, Dean W., Watson, Todd K., Nather, R. Edward, Montgomery, Michael Houston, Bischoff-Kim, Agnès, Hansen, Carl J., Nitta, Atsuko, Kleinman, Scot James, Claver, C.F., Brown, Tim, Sullivan, Denis J., Kim, Seung-Lee, Chen, Wen-Ping, Yang, M., Shih, Chia-You, Zhang, X, Jiang, Xiaojun, Fu, Jianning Ning, Seetha, S., Ashoka, B.N., Marar, T.M. Krishnan, Baliyan, Kiran S., Vats, Hari Om, Chernyshev, A.V., Ibbetson, Peter A., Leibowitz, Elia M., Hemar, Shirley, Sergeev, A., Andreev, M., Janulis, Rimvydas, Meistas, Edmundas G., Moskalik, Pawel, Pajdosz, Gabriel, Baran, Andrzej, Winiarski, M., Zola, Staszek, Ogloza, Waldemar, Siwak, Michal, Bognár, Zsófia, Solheim, Jan-Eric, Sefako, R., Buckley, David A.H., O'Donoghue, Darragh, Nagel, Thorsten, Silvotti, Roberto, Bruni, I., Fremy, J. R., Vauclair, Gérard, Chevreton, Michel, Dolez, Noël, Pfeiffer, Ben, Barstow, Martin A., Creevey, o, Kawaler, Steven D., Clemens, J. Christopher

Publikováno v: Repositório Institucional da UFRGS
Universidade Federal do Rio Grande do Sul (UFRGS)
instacron:UFRGS

PG 1351+489 is one of the 20DBVs – pulsating helium-atmospherewhite dwarf stars – known and has the simplest power spectrum for this class of star, making it a good candidate to study cooling rates. We report accurate period determinations for th

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=od______3056::d03745808ee70215fb9b16872abad91c

New pulsating db white dwarf stars from the Sloan Digital Sky Survey

Autor: Nitta, Atsuko, Kleinman, Scot James, Krzesinski, Jerzy, Kepler, Souza Oliveira, Metcalfe, Travis S., Mukadam, Anjum Shagufta, Mullally, Fergal, Nather, R. Edward, Sullivan, Denis J., Thompson, S. E., Winget, Donald Earl

Publikováno v: Repositório Institucional da UFRGS
Universidade Federal do Rio Grande do Sul (UFRGS)
instacron:UFRGS

We are searching for new He atmosphere white dwarf pulsators (DBVs) based on the newly found white dwarf stars from the spectra obtained by the Sloan Digital Sky Survey. DBVs pulsate at hotter temperature ranges than their better known cousins, the H

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=od______3056::2e028429a8bfe2c887bb1e4a3ef9298f