O Projeto
SAGAN
O SAGAN é uma plataforma web para explorar, direto no navegador, as curvas de luz do telescópio espacial
TESS 7
Em 2 de outubro de 2026, o catálogo de TESS Objects of Interest tinha 8.148 entradas, e três em cada quatro
ainda eram candidatos sem confirmação
1 ,2 3
O que dá para fazer
Buscar e filtrar o catálogo TOI, lido ao vivo do ExoFOP-TESS1
Listar as observações de cada estrela no arquivo MAST e abrir a curva de luz.
Aplicar e combinar as operações do Lightkurve4
Encontrar o período com um periodograma BLS5
Exportar o gráfico em PNG e os dados em CSV.
A página Teoria explica a física e cada ferramenta, com as fontes científicas; o guia mostra o passo a passo.
Como funciona
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Arquitetura do SAGAN
O navegador conversa com uma função Django na Vercel. A função busca o catálogo TOI no ExoFOP (com cache de uma hora) e as curvas de luz no MAST pelo lightkurve.
Navegador
gráficos + pipeline
Django (Vercel)
função Python stateless
ExoFOP-TESS (IPAC)
catálogo TOI · CSV
MAST (STScI)
curvas de luz · FITS
páginas
JSON
cache 1 h
lightkurve
O navegador guarda a lista de
funções aplicadas e a reenvia
a cada mudança; o servidor valida
e recalcula a partir da curva base.
Figura. Arquitetura do SAGAN. O servidor não guarda estado: a lista de funções aplicadas fica no navegador e cada requisição é recalculada a partir da curva original, o que permite rodar como função serverless.
O backend é Django 5.2 em Python 3.13, publicado na Vercel. O catálogo TOI vem do ExoFOP-TESS e fica em cache
por uma hora. As curvas de luz são baixadas do MAST pelo Lightkurve4 6 GitHub .
Limites
O SAGAN é uma ferramenta de exploração e ensino, não um pipeline de validação. As disposições exibidas são as
do catálogo oficial. O periodograma automático acha o período mais provável, mas não faz os testes de falso
positivo (centroide, profundidade par/ímpar, eclipse secundário) descritos pela equipe do TESS
3
História
O projeto começou em 2021–2022, hospedado em clebersfonseca/sagan ,
com um catálogo estático em CSV e gráficos simples. Em 2026 foi modernizado: Django 4 → 5.2, catálogo ao vivo,
pipeline de análise, periodograma BLS, nova interface, arquitetura sem estado para serverless e testes.
O nome homenageia o astrônomo Carl Sagan e é também uma sigla: Search, Ask, Gather, Analyze, Now .
Tecnologias
Python 3.13
Django 5.2
Lightkurve
Astropy
Pandas
Bootstrap 5
Google Charts
Vercel
Créditos dos dados
Este site usa dados coletados pela missão TESS, obtidos no arquivo MAST (Mikulski Archive for Space Telescopes)
do Space Telescope Science Institute. O financiamento da missão TESS vem do NASA Explorer Program. O catálogo
TOI vem do ExoFOP-TESS (NASA/IPAC). Ícones: Font Awesome (licença Free).
Referências
ExoFOP-TESS — Exoplanet Follow-up Observing Program, NASA/IPAC. exofop.ipac.caltech.edu/tess (acesso em 2 out. 2026).
NASA Exoplanet Archive. exoplanetarchive.ipac.caltech.edu (acesso em 2 out. 2026).
Guerrero, N. M. et al. (2021). The TESS Objects of Interest Catalog from the TESS Prime Mission. ApJS 254, 39. doi:10.3847/1538-4365/abefe1
Lightkurve Collaboration (2018). Lightkurve: Kepler and TESS time series analysis in Python. ascl:1812.013. ADS
Kovács, G.; Zucker, S.; Mazeh, T. (2002). A box-fitting algorithm in the search for periodic transits. A&A 391, 369. doi:10.1051/0004-6361:20020802
Jenkins, J. M. et al. (2016). The TESS Science Processing Operations Center. Proc. SPIE 9913, 99133E. doi:10.1117/12.2233418
Ricker, G. R. et al. (2015). Transiting Exoplanet Survey Satellite. JATIS 1, 014003. doi:10.1117/1.JATIS.1.1.014003