Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Proxima Centauri reloaded: Unravelling the stellar noise in radial velocities
KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
2017 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 599, article id A126Article in journal (Refereed) Published
Abstract [en]

Context. The detection and characterisation of Earth-like planets with Doppler signals of the order of 1 m s-1 currently represent one of the greatest challenge for extrasolar-planet hunters. As results for such findings are often controversial, it is desirable to provide independent confirmations of the discoveries. Testing different models for the suppression of non-Keplerian stellar signals usually plaguing radial velocity data is essential to ensuring findings are robust and reproducible. Aims. Using an alternative treatment of the stellar noise to that discussed in the discovery paper, we re-analyse the radial velocity dataset that led to the detection of a candidate terrestrial planet orbiting the star Proxima Centauri. We aim to confirm the existence of this outstanding planet, and test the existence of a second planetary signal. Methods. Our technique jointly modelled Keplerian signals and residual correlated signals in radial velocities using Gaussian processes. We analysed only radial velocity measurements without including other ancillary data in the fitting procedure. In a second step, we have compared our outputs with results coming from photometry, to provide a consistent physical interpretation. Our analysis was performed in a Bayesian framework to quantify the robustness of our findings. Results. We show that the correlated noise can be successfully modelled as a Gaussian process regression, and contains a periodic term modulated on the stellar rotation period and characterised by an evolutionary timescale of the order of one year. Both findings appear to be robust when compared with results obtained from archival photometry, thus providing a reliable description of the noise properties. We confirm the existence of a coherent signal described by a Keplerian orbit equation that can be attributed to the planet Proxima b, and provide an independent estimate of the planetary parameters. Our Bayesian analysis dismisses the existence of a second planetary signal in the present dataset.

Place, publisher, year, edition, pages
EDP Sciences, 2017. Vol. 599, article id A126
Keywords [en]
Planetary systems, Stars: individual: Proxima Centauri, Techniques: radial velocities, Earth (planet), Extrasolar planets, Gaussian distribution, Gaussian noise (electronic), Photometry, Stars, Velocity, Bayesian frameworks, Gaussian process regression, Physical interpretation, Planetary system, Radial velocity datum, Radial velocity measurements, Orbits
National Category
Probability Theory and Statistics
Identifiers
URN: urn:nbn:se:kth:diva-208050DOI: 10.1051/0004-6361/201630050Scopus ID: 2-s2.0-85015289234OAI: oai:DiVA.org:kth-208050DiVA, id: diva2:1104378
Note

QC 20170601

Available from: 2017-06-01 Created: 2017-06-01 Last updated: 2017-06-01Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Del Sordo, Fabio
By organisation
Nordic Institute for Theoretical Physics NORDITA
In the same journal
Astronomy and Astrophysics
Probability Theory and Statistics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 17 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf