Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFS |
Texto Completo: | https://ri.ufs.br/jspui/handle/riufs/14726 |
Resumo: | We present a spectroscopic study of two classical T Tauri stars, Mon-667 and Mon-996, belonging to the young open cluster NGC 2264. These stars were observed during the CSI 2264 campaign of the FLAMES spectrograph in 2011. From the analysis of the light curves obtained in this campaign, these stars were classified as aperiodic. Using a periodicity study, we find that these stars presented periodicity in the Hα line (Sousa et al., 2016). This is an unusual behavior as aperiodic objects on the light curve are not expected to be periodic on the Hα line. The unexpected feature of these objects motivated the development of this work. To analyze the periodicity of these stars, we used the periodogram analysis for unevenly spaced data described by Scargle (1982). With this method we can verify if the objects continued to present periodicity in the Hα line in 2013, if the velocity intervals that presented periodicity in 2013 remained the same as in 2011, and if periods remained unchanged from the previous observations. From the comparison between the Hα line profiles of 2011 and 2013, we find that the Mon-996 Hα profile in 2013 maintained the same morphology of 2011. However, its periodogram changed considerably, having periodicity in non-periodic regions in 2011. The periodicity observed in the red wing of ~ 8 days remained less pronounced. Also, the blue wing started presenting periodicity, which may have been generated by the wind. We observed that the star Mon-667 showed a drastic change in its profile of the Hα line from 2011 to 2013, no longer in emission and showing absorption in that line. The periodic velocity range and the period of the spectral region have been modified. The absorption spectral region presented a periodicity of ~ 3 days. We examined the correlation of the Hα line profile variability of the studied objects using the correlation matrix calculation method. In 2013, the blue and red wings of the Hα profile of the star Mon-996 showed a good correlation with themselves. However, there was no good correlation between one wing and another. Also, we realize that there is an anticorrelation region between these wings at velocity ranges of ~ -50 to ~ -200 km/s and ~ 100 to ~ 200 km/s. These regions correspond to emission in blue and red wings, which vary anti-phase. Consequently, this results in anticorrelated variability between the wings. In Mon-667, there was a good correlation between the blue and red wings with themselves for velocities in the range of ~ -100 to ~ 0 km/s and ~ 0 to ~ 200 km/s. In addition, there was also a good correlation between the wings at these intervals. In the Hα line, we found that these velocity ranges correspond to the absorption region of the profile in the spectrum of some nights, which indicates that there is a single process causing the absorption in the Hα line of this star. In 2013, the absence of Hα in emission in the observed period indicates that the magnetospheric accretion decreased significantly, indicating that there was no emission in Mon-667. Although no emission occurred, we observed that the spectra of particular nights, the absorption was filled. Figuring out what may have caused a significant change in the Hα line profile for the Mon-667 case is hard to understand and is still an open question. |
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Silva, Marcus Vinicius Grilo daSouto, Diogo Martins2021-11-10T11:45:23Z2021-11-10T11:45:23Z2020-01-29SILVA, Marcus Vinicius Grilo da. Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264. 2020. 86 f. Dissertação (Mestrado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2020.https://ri.ufs.br/jspui/handle/riufs/14726We present a spectroscopic study of two classical T Tauri stars, Mon-667 and Mon-996, belonging to the young open cluster NGC 2264. These stars were observed during the CSI 2264 campaign of the FLAMES spectrograph in 2011. From the analysis of the light curves obtained in this campaign, these stars were classified as aperiodic. Using a periodicity study, we find that these stars presented periodicity in the Hα line (Sousa et al., 2016). This is an unusual behavior as aperiodic objects on the light curve are not expected to be periodic on the Hα line. The unexpected feature of these objects motivated the development of this work. To analyze the periodicity of these stars, we used the periodogram analysis for unevenly spaced data described by Scargle (1982). With this method we can verify if the objects continued to present periodicity in the Hα line in 2013, if the velocity intervals that presented periodicity in 2013 remained the same as in 2011, and if periods remained unchanged from the previous observations. From the comparison between the Hα line profiles of 2011 and 2013, we find that the Mon-996 Hα profile in 2013 maintained the same morphology of 2011. However, its periodogram changed considerably, having periodicity in non-periodic regions in 2011. The periodicity observed in the red wing of ~ 8 days remained less pronounced. Also, the blue wing started presenting periodicity, which may have been generated by the wind. We observed that the star Mon-667 showed a drastic change in its profile of the Hα line from 2011 to 2013, no longer in emission and showing absorption in that line. The periodic velocity range and the period of the spectral region have been modified. The absorption spectral region presented a periodicity of ~ 3 days. We examined the correlation of the Hα line profile variability of the studied objects using the correlation matrix calculation method. In 2013, the blue and red wings of the Hα profile of the star Mon-996 showed a good correlation with themselves. However, there was no good correlation between one wing and another. Also, we realize that there is an anticorrelation region between these wings at velocity ranges of ~ -50 to ~ -200 km/s and ~ 100 to ~ 200 km/s. These regions correspond to emission in blue and red wings, which vary anti-phase. Consequently, this results in anticorrelated variability between the wings. In Mon-667, there was a good correlation between the blue and red wings with themselves for velocities in the range of ~ -100 to ~ 0 km/s and ~ 0 to ~ 200 km/s. In addition, there was also a good correlation between the wings at these intervals. In the Hα line, we found that these velocity ranges correspond to the absorption region of the profile in the spectrum of some nights, which indicates that there is a single process causing the absorption in the Hα line of this star. In 2013, the absence of Hα in emission in the observed period indicates that the magnetospheric accretion decreased significantly, indicating that there was no emission in Mon-667. Although no emission occurred, we observed that the spectra of particular nights, the absorption was filled. Figuring out what may have caused a significant change in the Hα line profile for the Mon-667 case is hard to understand and is still an open question.Apresentamos neste trabalho um estudo espectroscópico das estrelas T Tauri clássicas Mon-667 e Mon-996, pertencentes ao aglomerado estelar jovem NGC 2264. Essas estrelas foram observadas durante a campanha CSI 2264 pelo espectrógrafo FLAMES em 2011. Da análise das curvas de luz obtidas nesta campanha, essas estrelas foram classificadas como aperiódicas. Foi também realizado um estudo da periodicidade da linha Hα, e através desse estudo verificou-se que essas estrelas apresentavam periodicidade na linha Hα (Sousa et al., 2016). Esse é um comportamento incomum, pois não espera-se que objetos aperiódicos na curva de luz sejam periódicos na linha Hα. Essa característica inesperada desses objetos motivou o desenvolvimento desse trabalho. Para analisar a periodicidade das estrelas foi utilizado o método de análise de periodogramas descrito por Scargle (1982) para dados não igualmente espaçados. Esse método permite verificar se os objetos continuaram apresentando periodicidade na linha Hα em 2013, se os intervalos de velocidades que apresentam periodicidade em 2013 permaneceram os mesmos de 2011 e se os períodos se mantiveram inalterados ou se modificaram com relação às observações anteriores. Da comparação entre os perfis da linha Hα de 2011 e 2013, verificou-se que o perfil Hα de Mon 996 em 2013 manteve a mesma morfologia de 2011. No entanto, seu periodograma modificou-se consideravelmente, mostrando periodicidade em regiões que não eram periódicas em 2011. A periodicidade observada na asa vermelha de ~ 8 dias se manteve de forma menos acentuada. E a asa azul passou também a ter periodicidade, que pode ter sido gerada por um vento. Observamos que a estrela Mon-667 apresentou uma mudança drástica em seu perfil da linha Hα de 2011 para 2013, deixando de ter emissão e passando a ter absorção nessa linha. O intervalo de velocidade que mostra periodicidade e também o período da região espectral foi modificado. A região espectral com absorção apresentou periodicidade de ~ 3 dias no intervalo de aproximadamente -100 à 200 km/s. Examinamos a correlação da variabilidade entre os intervalos de velocidade do perfil da linha Hα dos objetos de estudo utilizando o método do cálculo das matrizes de correlação. Em 2013, as asas azul e vermelha do perfil Hα da estrela Mon-996 apresentaram uma boa correlação entre si, porém não houve uma boa correlação entre uma asa e a outra. Além disso, percebemos que existe uma região de anticorrelação entre os intervalos de velocidade de ~ -50 a ~ -200 km/s e ~ 100 a ~ 200 km/s. Essas regiões correspondem às emissões nas asas azul e vermelha, que variam em anti-fase. Consequentemente, isso resulta na variabilidade anticorrelacionada entre as asas. Em Mon-667, houve uma boa correlação das asas azul e vermelha com elas próprias para velocidades no intervalo de ~ -100 a ~ 0 km/s e de ~ 0 a ~ 200 km/s. Além disso, houve também uma boa correlação entre as asas nesses intervalos. Na linha Hα, verificamos que esses intervalos de velocidade correspondem à região de absorção do perfil no espectro de algumas noites, o que evidencia que existe um único processo causando a absorção na linha Hα dessa estrela. Em 2013, a ausência de Hα em emissão no período observado indica que a acreção magnetosférica diminuiu de forma significativa, de tal modo que não houve emissão em Mon-667. Embora não tenha ocorrido emissão, observamos que nos espectros de algumas noites a absorção foi preenchida. O caso de Mon-667 é difícil de ser compreendido, e o que pode ter causado a grande mudança em seu perfil de linha Hα ainda é uma questão em aberto.Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SESão Cristóvão, SEporAstrofísicaFormação estelarEstrelas T TauriAcreçãoNGC 2264PeriodicidadeVariabilidadeLinha HαT Tauri StarsAccretionNGC 2264PeriodicityVariabilityLine HαCIENCIAS EXATAS E DA TERRA::FISICAEstudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisPós-Graduação em FísicaUniversidade Federal de Sergipereponame:Repositório Institucional da UFSinstname:Universidade Federal de Sergipe (UFS)instacron:UFSinfo:eu-repo/semantics/openAccessLICENSElicense.txtlicense.txttext/plain; charset=utf-81475https://ri.ufs.br/jspui/bitstream/riufs/14726/1/license.txt098cbbf65c2c15e1fb2e49c5d306a44cMD51ORIGINALMARCUS_VINICIUS_GRILO_SILVA.pdfMARCUS_VINICIUS_GRILO_SILVA.pdfapplication/pdf17962622https://ri.ufs.br/jspui/bitstream/riufs/14726/2/MARCUS_VINICIUS_GRILO_SILVA.pdf54a21dc629b9b206d6cefeac9d5b26b7MD52TEXTMARCUS_VINICIUS_GRILO_SILVA.pdf.txtMARCUS_VINICIUS_GRILO_SILVA.pdf.txtExtracted texttext/plain161508https://ri.ufs.br/jspui/bitstream/riufs/14726/3/MARCUS_VINICIUS_GRILO_SILVA.pdf.txt3a55ee55b4ea299475917fd40fffa048MD53THUMBNAILMARCUS_VINICIUS_GRILO_SILVA.pdf.jpgMARCUS_VINICIUS_GRILO_SILVA.pdf.jpgGenerated Thumbnailimage/jpeg1505https://ri.ufs.br/jspui/bitstream/riufs/14726/4/MARCUS_VINICIUS_GRILO_SILVA.pdf.jpgcb38c2111ceae59902fa5dd29ec1edc1MD54riufs/147262021-11-10 08:45:23.977oai:ufs.br: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Repositório InstitucionalPUBhttps://ri.ufs.br/oai/requestrepositorio@academico.ufs.bropendoar:2021-11-10T11:45:23Repositório Institucional da UFS - Universidade Federal de Sergipe (UFS)false |
dc.title.pt_BR.fl_str_mv |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 |
title |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 |
spellingShingle |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 Silva, Marcus Vinicius Grilo da Astrofísica Formação estelar Estrelas T Tauri Acreção NGC 2264 Periodicidade Variabilidade Linha Hα T Tauri Stars Accretion NGC 2264 Periodicity Variability Line Hα CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 |
title_full |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 |
title_fullStr |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 |
title_full_unstemmed |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 |
title_sort |
Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264 |
author |
Silva, Marcus Vinicius Grilo da |
author_facet |
Silva, Marcus Vinicius Grilo da |
author_role |
author |
dc.contributor.author.fl_str_mv |
Silva, Marcus Vinicius Grilo da |
dc.contributor.advisor1.fl_str_mv |
Souto, Diogo Martins |
contributor_str_mv |
Souto, Diogo Martins |
dc.subject.por.fl_str_mv |
Astrofísica Formação estelar Estrelas T Tauri Acreção NGC 2264 Periodicidade Variabilidade Linha Hα T Tauri Stars Accretion NGC 2264 Periodicity Variability Line Hα |
topic |
Astrofísica Formação estelar Estrelas T Tauri Acreção NGC 2264 Periodicidade Variabilidade Linha Hα T Tauri Stars Accretion NGC 2264 Periodicity Variability Line Hα CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
We present a spectroscopic study of two classical T Tauri stars, Mon-667 and Mon-996, belonging to the young open cluster NGC 2264. These stars were observed during the CSI 2264 campaign of the FLAMES spectrograph in 2011. From the analysis of the light curves obtained in this campaign, these stars were classified as aperiodic. Using a periodicity study, we find that these stars presented periodicity in the Hα line (Sousa et al., 2016). This is an unusual behavior as aperiodic objects on the light curve are not expected to be periodic on the Hα line. The unexpected feature of these objects motivated the development of this work. To analyze the periodicity of these stars, we used the periodogram analysis for unevenly spaced data described by Scargle (1982). With this method we can verify if the objects continued to present periodicity in the Hα line in 2013, if the velocity intervals that presented periodicity in 2013 remained the same as in 2011, and if periods remained unchanged from the previous observations. From the comparison between the Hα line profiles of 2011 and 2013, we find that the Mon-996 Hα profile in 2013 maintained the same morphology of 2011. However, its periodogram changed considerably, having periodicity in non-periodic regions in 2011. The periodicity observed in the red wing of ~ 8 days remained less pronounced. Also, the blue wing started presenting periodicity, which may have been generated by the wind. We observed that the star Mon-667 showed a drastic change in its profile of the Hα line from 2011 to 2013, no longer in emission and showing absorption in that line. The periodic velocity range and the period of the spectral region have been modified. The absorption spectral region presented a periodicity of ~ 3 days. We examined the correlation of the Hα line profile variability of the studied objects using the correlation matrix calculation method. In 2013, the blue and red wings of the Hα profile of the star Mon-996 showed a good correlation with themselves. However, there was no good correlation between one wing and another. Also, we realize that there is an anticorrelation region between these wings at velocity ranges of ~ -50 to ~ -200 km/s and ~ 100 to ~ 200 km/s. These regions correspond to emission in blue and red wings, which vary anti-phase. Consequently, this results in anticorrelated variability between the wings. In Mon-667, there was a good correlation between the blue and red wings with themselves for velocities in the range of ~ -100 to ~ 0 km/s and ~ 0 to ~ 200 km/s. In addition, there was also a good correlation between the wings at these intervals. In the Hα line, we found that these velocity ranges correspond to the absorption region of the profile in the spectrum of some nights, which indicates that there is a single process causing the absorption in the Hα line of this star. In 2013, the absence of Hα in emission in the observed period indicates that the magnetospheric accretion decreased significantly, indicating that there was no emission in Mon-667. Although no emission occurred, we observed that the spectra of particular nights, the absorption was filled. Figuring out what may have caused a significant change in the Hα line profile for the Mon-667 case is hard to understand and is still an open question. |
publishDate |
2020 |
dc.date.issued.fl_str_mv |
2020-01-29 |
dc.date.accessioned.fl_str_mv |
2021-11-10T11:45:23Z |
dc.date.available.fl_str_mv |
2021-11-10T11:45:23Z |
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info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
SILVA, Marcus Vinicius Grilo da. Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264. 2020. 86 f. Dissertação (Mestrado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2020. |
dc.identifier.uri.fl_str_mv |
https://ri.ufs.br/jspui/handle/riufs/14726 |
identifier_str_mv |
SILVA, Marcus Vinicius Grilo da. Estudo espectroscópico de estrelas T Tauri no aglomerado NGC 2264. 2020. 86 f. Dissertação (Mestrado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2020. |
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Pós-Graduação em Física |
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Universidade Federal de Sergipe |
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