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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

The Solar Twin Planet Search IV. The Sun as a typical rotator and evidence for a new rotational braking law for Sun-like stars

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dos Santos, Leonardo A. ; Melendez, Jorge ; do Nascimento, Jr., Jose-Dias ; Bedell, Megan ; Ramirez, Ivan ; Bean, Jacob L. ; Asplund, Martin ; Spina, Lorenzo ; Dreizler, Stefan ; Alves-Brito, Alan ; Casagrande, Luca
Número total de Autores: 11
Tipo de documento: Artigo Científico
Fonte: Astronomy & Astrophysics; v. 592, AUG 2016.
Citações Web of Science: 12
Resumo

Context. It is still unclear how common the Sun is when compared to other similar stars in regards to some of its physical properties, such as rotation. Considering that gyrochronology relations are widely used today to estimate ages of stars in the main sequence, and that the Sun is used to calibrate it, it is crucial to assess whether these procedures are acceptable. Aims. We analyze the rotational velocities, limited by the unknown rotation axis inclination angle, of an unprecedented large sample of solar twins to study the rotational evolution of Sun-like stars, and assess whether the Sun is a typical rotator. Methods. We used high-resolution (R = 115 000) spectra obtained with the HARPS spectrograph and the 3.6 m telescope at La Silla Observatory. The projected rotational velocities for 81 solar twins were estimated by line profile fitting with synthetic spectra. Macro-turbulence velocities were inferred from a prescription that accurately reflects their dependence with effective temperature and luminosity of the stars. Results. Our sample of solar twins include some spectroscopic binaries with enhanced rotational velocities, and we do not find any nonspectroscopic binaries with unusually high rotation velocities. We verified that the Sun does not have a peculiar rotation, but the solar twins exhibit rotational velocities that depart from the Skumanich relation. Conclusions. The Sun is a regular rotator when compared to solar twins with a similar age. Additionally, we obtain a rotational braking law that better describes the stars in our sample (v proportional to t(-0.6)) in contrast to previous, often-used scalings. (AU)

Processo FAPESP: 16/01684-9 - Revelando as órbitas de gêmeas solares binárias com rotação elevada
Beneficiário:Leonardo Augusto Gonçalves dos Santos
Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Mestrado
Processo FAPESP: 12/24392-2 - Espectroscopia de alta precisão: impacto no estudo de planetas, estrelas, a galáxia e cosmologia
Beneficiário:Jorge Luis Melendez Moreno
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 14/26908-1 - Quão comum é nosso sol no seu período de rotação?
Beneficiário:Leonardo Augusto Gonçalves dos Santos
Linha de fomento: Bolsas no Brasil - Mestrado
Processo FAPESP: 14/15706-9 - Abundâncias diferenciais em estrelas de tipo solar: implicações sobre a formação de planetas e nucleossíntese estelar
Beneficiário:Lorenzo Spina
Linha de fomento: Bolsas no Brasil - Pós-Doutorado