Abstract
Stellar activity is the major roadblock on the path to finding true Earth-analogue planets with the Doppler technique. Thus, identifying new indicators that better trace magnetic activity (i.e. faculae and spots) is crucial to aid in disentangling these signals from that of a planet's Doppler wobble. In this work, we investigate activity related features as seen in disc-integrated spectra from the HARPS-N solar telescope. We divide high-activity spectral echelle orders by low-activity master templates (as defined using both logR _ HK and images from the Solar Dynamics Observatory, SDO), creating 'relative spectra'.With resolved images of the surface of the Sun (via SDO), the faculae and spot filling factors can be calculated, giving a measure of activity independent of, and in addition to, logR ' HK.We find pseudo-emission (and pseudoabsorption) features in the relative spectra that are similar to those reported in our previous work on α Cen B. In α Cen B, the features are shown to correlate better to changes in faculae filling factor than spot filling factor. In this work, we more confidently identify changes in faculae coverage of the visible hemisphere of the Sun as the source of features produced in the relative spectra. Finally, we produce trailed spectra to observe the radial velocity component of the features, which show that the features move in a redward direction as one would expect when tracking active regions rotating on the surface of a star.
| Original language | English |
|---|---|
| Pages (from-to) | 4279-4290 |
| Number of pages | 12 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 494 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - May 2020 |
Bibliographical note
Funding Information:AM acknowledges support from the senior Kavli Institute Fellowships.
Funding Information:
XD is grateful to The Branco Weiss Fellowship – Society in Science for its financial support.
Funding Information:
SHS is grateful for support from NASA Heliophysics LWS grant NNX16AB79G. HMC acknowledges the financial support of the National Centre for Competence in Research Planets supported by the Swiss National Science Foundation (SNSF).
Funding Information:
This publication was made possible through the support of a grant from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This work was performed in part under contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (in support of RDH).
Funding Information:
CAW acknowledges support from Science and Technology Facilities Council grant ST/P000312/1.
Funding Information:
ACC acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant number ST/R000824/1.
Funding Information:
The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen’s University Belfast, and the University of Edinburgh.
Funding Information:
This work was performed partly under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (RDH).
Publisher Copyright:
© 2020 Oxford University Press. All rights reserved.
Keywords
- Planets and satellites: Detection
- Sun: Activity
- Sun: Faculae, plages
- Techniques: Radial velocities
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science