Skip navigation
  • INAF logo
  • Home
  • Communities
    & Collections
  • Research outputs
  • Researchers
  • Organization units
  • Projects
  • Explore by
    • Research outputs
    • Researchers
    • Organization units
    • Projects
  • Login:
    • My DSpace
    • Receive email
      updates
    • Edit Account details
  • Italian
  • English

  1. OA@INAF
  2. PRODOTTI RICERCA INAF
  3. 1 CONTRIBUTI IN RIVISTE (Journal articles)
  4. 1.01 Articoli in rivista
Please use this identifier to cite or link to this item: http://hdl.handle.net/20.500.12386/29104
Title: Revisiting Spitzer Transit Observations with Independent Component Analysis: New Results for the GJ 436 System
Authors: Morello, G.
Waldmann, I. P.
Tinetti, G.
Howarth, I. D.
MICELA, Giuseppina 
Allard, F.
Issue Date: 2015
Journal: THE ASTROPHYSICAL JOURNAL 
Number: 802
Issue: 2
First Page: 117
Abstract: We analyzed four Spitzer/IRAC observations at 3.6 and 4.5 μm of the primary transit of the exoplanet GJ 436b, by using blind source separation techniques. These observations are important for investigating the atmospheric composition of the planet GJ 436b. Previous analyses claimed strong inter-epoch variations of the transit parameters due to stellar variability, casting doubts on the possibility of conclusively extracting an atmospheric signal. Those analyses also reported discrepant results, hence the necessity of this reanalysis. The method we used has been proposed in Morello et al. to analyze 3.6 μm transit light curves of the hot Jupiter HD 189733b. It performes an Independent Component Analysis on a set of pixel light curves, i.e., time series read by individual pixels, from the same photometric observation. Our method only assumes the independence of instrumental and astrophysical signals, and therefore guarantees a higher degree of objectivity compared to parametric detrending techniques published in the literature. The data sets we analyzed in this paper represent a more challenging test than the previous ones. Contrary to previous results reported in the literature, our results (1) do not support any detectable inter-epoch variations of orbital and stellar parameters, (2) are photometrically stable at the level ̃10<SUP>-4</SUP> in the IR, and (3) the transit depth measurements at the two wavelengths are consistent within 1σ. We also (4) detect a possible transit duration variation of ̃80 s (2σ significance level) that has not been pointed out in the literature, and (5) confirm no transit timing variations ≳30 s.
Acknowledgments: G.M. is funded by UCL Perren/Impact scholarship (CJ4M/CJ0T). I.P.W. is funded by the European Research Council Grant “Exolights.” G.T. is funded by the Royal Society. G.M. is supported by “Progetto Premiale-A Way to Other Worlds”, funded by the Italian Minister for University and Scientific Research.
URI: http://hdl.handle.net/20.500.12386/29104
URL: https://iopscience.iop.org/article/10.1088/0004-637X/802/2/117
ISSN: 0004-637X
DOI: 10.1088/0004-637X/802/2/117
Bibcode ADS: 2015ApJ...802..117M
Fulltext: open
Appears in Collections:1.01 Articoli in rivista

Files in This Item:
File Description SizeFormat 
Morello_2015_ApJ_802_117.pdfpdf editoriale1.15 MBAdobe PDFView/Open
Show full item record

Page view(s)

5
checked on Jan 22, 2021

Download(s)

2
checked on Jan 22, 2021

Google ScholarTM

Check

Altmetric


Items in DSpace are published in Open Access, unless otherwise indicated.


Explore by
  • Communities
    & Collections
  • Research outputs
  • Researchers
  • Organization units
  • Projects

Informazioni e guide per autori

https://openaccess-info.inaf.it: tutte le informazioni sull'accesso aperto in INAF

Come si inserisce un prodotto: le guide a OA@INAF

La Policy INAF sull'accesso aperto

Documenti e modelli scaricabili

Feedback
Built with DSpace-CRIS - Extension maintained and optimized by Logo 4SCIENCE