Stellar surface magnetoconvection as a source of astrophysical noise. III. Sun-as-a-star simulations and optimal noise diagnostics

Cegla, HM, Watson, CA, Shelyag, Sergiy, Mathioudakis, M and Moutari, S 2019, Stellar surface magnetoconvection as a source of astrophysical noise. III. Sun-as-a-star simulations and optimal noise diagnostics, Astrophysical journal, vol. 879, no. 1, pp. 1-29, doi: 10.3847/1538-4357/ab16d3.

Attached Files
Name Description MIMEType Size Downloads

Title Stellar surface magnetoconvection as a source of astrophysical noise. III. Sun-as-a-star simulations and optimal noise diagnostics
Author(s) Cegla, HM
Watson, CA
Shelyag, SergiyORCID iD for Shelyag, Sergiy orcid.org/0000-0002-6436-9347
Mathioudakis, M
Moutari, S
Journal name Astrophysical journal
Volume number 879
Issue number 1
Article ID 55
Start page 1
End page 29
Total pages 29
Publisher IOP Publishing
Place of publication Bristol, Eng.
Publication date 2019-07-01
ISSN 0004-637X
Keyword(s) line: profiles
planets and satellites: detection
stars: activity
stars: low-mass
Sun: granulation
techniques: radial velocities
Summary Stellar surface magnetoconvection (granulation) creates asymmetries in the observed stellar absorption lines that can subsequently manifest themselves as spurious radial velocities (RVs) shifts. In turn, this can then mask the Doppler reflex motion induced by orbiting planets on their host stars and represents a particular challenge for determining the masses of low-mass, long-period planets. Herein, we study this impact by creating Sun-as-a-star observations that encapsulate the granulation variability expected from 3D magnetohydrodynamic simulations. These Sun-as-a-star model observations are in good agreement with empirical observations of the Sun but may underestimate the total variability relative to the quiet Sun due to the increased magnetic field strength in our models. We find numerous line profile characteristics that linearly correlate with the disk-integrated convection-induced velocities. Removing the various correlations with the line bisector, equivalent width, and the V asy indicator may reduce ~50%–60% of the granulation noise in the measured velocities. We also find that simultaneous photometry may be a key diagnostic, as our proxy for photometric brightness also allowed us to remove ~50% of the granulation-induced RV noise. These correlations and granulation-noise mitigations break down in the presence of low instrumental resolution and/or increased stellar rotation, as both act to smooth the observed line profile asymmetries.
Language eng
DOI 10.3847/1538-4357/ab16d3
Indigenous content off
Field of Research 0201 Astronomical and Space Sciences
0305 Organic Chemistry
0306 Physical Chemistry (incl. Structural)
HERDC Research category C1 Refereed article in a scholarly journal
Copyright notice ©2019, The American Astronomical Society
Persistent URL http://hdl.handle.net/10536/DRO/DU:30125228

Connect to link resolver
 
Unless expressly stated otherwise, the copyright for items in DRO is owned by the author, with all rights reserved.

Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 0 times in TR Web of Science
Scopus Citation Count Cited 1 times in Scopus
Google Scholar Search Google Scholar
Access Statistics: 15 Abstract Views, 2 File Downloads  -  Detailed Statistics
Created: Tue, 09 Jul 2019, 15:45:50 EST

Every reasonable effort has been made to ensure that permission has been obtained for items included in DRO. If you believe that your rights have been infringed by this repository, please contact drosupport@deakin.edu.au.