lessons from ”sun-as-a-star” observations€¦ · the sun is the only star we know that has no...
TRANSCRIPT
![Page 1: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/1.jpg)
Lessons from”Sun-as-a-star” observations
Annelies MortierKavli Fellow, University of Cambridge
Sagan Exoplanet Workshop, July 2020
![Page 2: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/2.jpg)
Exoplanet discoveries have risen exponentially
Annelies Mortier Sun-as-a-star 1 / 51
![Page 3: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/3.jpg)
Have we hit an RV barrier?
Better instruments and better modeling techniqueshave pushed towards the smallest signals.
Source: NASA Exoplanet archive
Annelies Mortier Sun-as-a-star 2 / 51
![Page 4: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/4.jpg)
Know the star, know the planet
You can only knowan exoplanetif you knowits host star!
Annelies Mortier Sun-as-a-star 3 / 51
![Page 5: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/5.jpg)
Know the star, find the planet
You can only //////know findan exoplanetif you knowits host star!
Annelies Mortier Sun-as-a-star 4 / 51
![Page 6: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/6.jpg)
The most problematic ’noise’ in RV data: the star
(Source: NASA/ESA. See also recently released SDO’s timelapse video!)
Stars are not static; like the Sun, they go through activity cycles.To find an Earth twin, we will need to understand stellar variability.
Annelies Mortier Sun-as-a-star 5 / 51
![Page 7: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/7.jpg)
Benefits from ”Sun-as-a-star” observations
(Source: www.britannica.com)
The Sun is the only star we know that has no orbiting planets...
Because we can remove them from the data.
Annelies Mortier Sun-as-a-star 6 / 51
![Page 8: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/8.jpg)
Benefits from ”Sun-as-a-star” observations
(Source: www.britannica.com)
The Sun is the only star we know that has no orbiting planets...Because we can remove them from the data.
Annelies Mortier Sun-as-a-star 6 / 51
![Page 9: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/9.jpg)
Stellar activity happens on multiple timescales
(Source: Cesar - ESA)
Solar magnetic cycle is roughly 11 years.Solar rotational effects are seen on 25-30d timescales.
Then there’s granulation, oscillations, flows, ...happening on timescales from minutes to hours to days.
See also talk by Heather Cegla.
Annelies Mortier Sun-as-a-star 7 / 51
![Page 10: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/10.jpg)
Sun-as-a-star observations for EPRV work
SimulationsUsing full simulated spectra: e.g. Desort+ 2007,Lagrange+ 2010,Meunier+ 2010, Gilbertson+ 2020Using simulated cross-correlation functions: SOAP/SOAP2.0 - Boisse+2012, Dumusque+ 2014
Indirect observationsVia Moon/asteroids: Lanza+ 16, Haywood+ 16Reconstructed from resolved observations: Meunier+ 2010 (MDI),Milbourne+ 2019 (SDO), Haywood+ 2020 (SDO)
Direct observationsHARPS-N solar telescope: Dumusque+ 2015, Phillips+ 2016, CollierCameron+ 2019 (contains 3yr of RV data). First 3yr of spectra to bereleased on 1st September 2020.HELIOS installed at HARPS: First data public in October 2020 (2-yrrolling proprietary period)Other ultra-high res observations exist, e.g. Kitt Peak solar spectra(Wallace+ 2011), IAG solar atlas (Reiners+ 2016), ..., thoughprecision/stability is not at m/s level.
Annelies Mortier Sun-as-a-star 8 / 51
![Page 11: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/11.jpg)
Sun-as-a-star observations for EPRV work
SimulationsUsing full simulated spectra: e.g. Desort+ 2007,Lagrange+ 2010,Meunier+ 2010, Gilbertson+ 2020Using simulated cross-correlation functions: SOAP/SOAP2.0 - Boisse+2012, Dumusque+ 2014
Indirect observationsVia Moon/asteroids: Lanza+ 16, Haywood+ 16Reconstructed from resolved observations: Meunier+ 2010 (MDI),Milbourne+ 2019 (SDO), Haywood+ 2020 (SDO)
Direct observationsHARPS-N solar telescope: Dumusque+ 2015, Phillips+ 2016, CollierCameron+ 2019 (contains 3yr of RV data). First 3yr of spectra to bereleased on 1st September 2020.HELIOS installed at HARPS: First data public in October 2020 (2-yrrolling proprietary period)Other ultra-high res observations exist, e.g. Kitt Peak solar spectra(Wallace+ 2011), IAG solar atlas (Reiners+ 2016), ..., thoughprecision/stability is not at m/s level.
Annelies Mortier Sun-as-a-star 9 / 51
![Page 12: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/12.jpg)
RVs from simulated spectra: spots and plages
(Meunier, Desort, Lagrange 2010)
RVs from spots and plages: generally the amplitude stays below 2m/s.
Annelies Mortier Sun-as-a-star 10 / 51
![Page 13: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/13.jpg)
RVs from simulated spectra: convective blueshift
(Meunier, Desort, Lagrange 2010)
Suppression of convective blueshift is main source of solar RV variation.
Annelies Mortier Sun-as-a-star 11 / 51
![Page 14: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/14.jpg)
Suppression of convective blueshift
(courtesy R. Haywood)
Suppression of convective blueshift makes RV vary with several m/s.Faculae are main source of this suppression.
Time scales related both to magnetic cycle and rotation period.See talk by Heather Cegla.
Annelies Mortier Sun-as-a-star 12 / 51
![Page 15: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/15.jpg)
Simulated CCFs with SOAP/SOAP2.0
(Dumusque et al. 2014)
Spot Oscillation And Planet (SOAP) simulates CCFs across a stellar disc.Annelies Mortier Sun-as-a-star 13 / 51
![Page 16: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/16.jpg)
Sun-as-a-star observations for EPRV work
SimulationsUsing full simulated spectra: e.g. Desort+ 2007,Lagrange+ 2010,Meunier+ 2010, Gilbertson+ 2020Using simulated cross-correlation functions: SOAP/SOAP2.0 - Boisse+2012, Dumusque+ 2014
Indirect observationsVia Moon/asteroids: Lanza+ 16, Haywood+ 16Reconstructed from resolved observations: Meunier+ 2010 (MDI),Milbourne+ 2019 (SDO), Haywood+ 2020 (SDO)
Direct observationsHARPS-N solar telescope: Dumusque+ 2015, Phillips+ 2016, CollierCameron+ 2019 (contains 3yr of RV data). First 3yr of spectra to bereleased on 1st September 2020.HELIOS installed at HARPS: First data public in October 2020 (2-yrrolling proprietary period)Other ultra-high res observations exist, e.g. Kitt Peak solar spectra(Wallace+ 2011), IAG solar atlas (Reiners+ 2016), ..., thoughprecision/stability is not at m/s level.
Annelies Mortier Sun-as-a-star 14 / 51
![Page 17: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/17.jpg)
Indirect observations: Reconstructing from MDI/SOHO
(Meunier, Lagrange, Desort 2010)
RVs from disc-resolved observations confirm the simulations.
Annelies Mortier Sun-as-a-star 15 / 51
![Page 18: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/18.jpg)
Indirect observations: Using the asteroid Vesta
(Haywood et al. 2016)
Hemispherically-averaged line-of-sight magnetic flux density, B,correlates well with RV.
It outperforms other standard activity indicators (see also Jenn Burt’s talk).
Annelies Mortier Sun-as-a-star 16 / 51
![Page 19: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/19.jpg)
Indirect observations: Using the asteroid Vesta
(Haywood et al. 2016)
Hemispherically-averaged line-of-sight magnetic flux density, B,correlates well with RV.
It outperforms other standard activity indicators (see also Jenn Burt’s talk).
Annelies Mortier Sun-as-a-star 16 / 51
![Page 20: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/20.jpg)
Indirect observations: Reconstructing from SDO
(Haywood et al. 2020)
A simple linear fit with the unsigned magnetic flux reduces therms of solar RV variations by 62% (factor of 2.6).
Annelies Mortier Sun-as-a-star 17 / 51
![Page 21: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/21.jpg)
Sun-as-a-star observations for EPRV work
SimulationsUsing full simulated spectra: e.g. Desort+ 2007,Lagrange+ 2010,Meunier+ 2010, Gilbertson+ 2020Using simulated cross-correlation functions: SOAP/SOAP2.0 - Boisse+2012, Dumusque+ 2014
Indirect observationsVia Moon/asteroids: Lanza+ 16, Haywood+ 16Reconstructed from resolved observations: Meunier+ 2010 (MDI),Milbourne+ 2019 (SDO), Haywood+ 2020 (SDO)
Direct observationsHARPS-N solar telescope: Dumusque+ 2015, Phillips+ 2016, CollierCameron+ 2019 (contains 3yr of RV data). First 3yr of spectra to bereleased on 1st September 2020.HELIOS installed at HARPS: First data public in October 2020 (2-yrrolling proprietary period)Other ultra-high res observations exist, e.g. Kitt Peak solar spectra(Wallace+ 2011), IAG solar atlas (Reiners+ 2016), ..., thoughprecision/stability is not at m/s level.
Annelies Mortier Sun-as-a-star 18 / 51
![Page 22: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/22.jpg)
The solar telescope feeding into HARPS-N
Courtesy: A. Glenday
Annelies Mortier Sun-as-a-star 19 / 51
![Page 23: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/23.jpg)
The solar telescope feeding into HARPS-N
Operational since July 2015.Daily 5-minute exposures from 9am till ∼4pm.
Courtesy: A. Glenday
Annelies Mortier Sun-as-a-star 19 / 51
![Page 24: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/24.jpg)
HELIOS: The solar telescope feeding into HARPS
Courtesy: X. Dumusque
Operational since October 2018. Daily 5-minute exposures.PIs: X. Dumusque & P. Figueira
Annelies Mortier Sun-as-a-star 20 / 51
![Page 25: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/25.jpg)
Why take 5-min exposures?
(using HARPS-N solar data)
5-minute exposures average over the oscillation variations.Carefully tailored stellar exposure times are worth it.
See also Dumusque+ 2011, Chaplin+ 2019.
Annelies Mortier Sun-as-a-star 21 / 51
![Page 26: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/26.jpg)
Why take 5-min exposures?
(using HARPS-N solar data)
5-minute exposures average over the oscillation variations.Carefully tailored stellar exposure times are worth it.
See also Dumusque+ 2011, Chaplin+ 2019.Annelies Mortier Sun-as-a-star 21 / 51
![Page 27: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/27.jpg)
Let’s look at the data
Annelies Mortier Sun-as-a-star 22 / 51
![Page 28: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/28.jpg)
Jupiter clearly detected
- corrected using JPL Horizons
(Adapted from Collier Cameron, Mortier et al. 2019)
Annelies Mortier Sun-as-a-star 23 / 51
![Page 29: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/29.jpg)
Jupiter clearly detected - corrected using JPL Horizons
(Adapted from Collier Cameron, Mortier et al. 2019)
Annelies Mortier Sun-as-a-star 23 / 51
![Page 30: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/30.jpg)
Daily downwards trend
- due to differential extinction?
(Adapted from Collier Cameron, Mortier et al. 2019)
Unlike stars, the Sunis resolved in the sky,
creating additionalissues in treating it as
a star.
Annelies Mortier Sun-as-a-star 24 / 51
![Page 31: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/31.jpg)
Daily downwards trend - due to differential extinction?
(Adapted from Collier Cameron, Mortier et al. 2019)
Unlike stars, the Sunis resolved in the sky,
creating additionalissues in treating it as
a star.
Annelies Mortier Sun-as-a-star 24 / 51
![Page 32: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/32.jpg)
Correct for differential extinction - rms still 1.6 m/s!
(Adapted from Collier Cameron, Mortier et al. 2019)
Annelies Mortier Sun-as-a-star 25 / 51
![Page 33: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/33.jpg)
HARPS-N now has 5 full years of data
First three years of spectra, CCFs (homogeneously reduced)will be released 1st September 2020 through DACE.
Annelies Mortier Sun-as-a-star 26 / 51
![Page 34: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/34.jpg)
Let’s remind ourselves again what we’re looking for
Finding an Earth twin remains a non-straightforward challenge,even for quiet stars (Sun is at solar minimum).
Annelies Mortier Sun-as-a-star 27 / 51
![Page 35: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/35.jpg)
The power of the HARPS-N – HELIOS combo
Courtesy X. Dumusque
Annelies Mortier Sun-as-a-star 28 / 51
![Page 36: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/36.jpg)
Activity-induced RV variations are unpredictable
Courtesy X. Dumusque
Annelies Mortier Sun-as-a-star 29 / 51
![Page 37: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/37.jpg)
Issues revealed with daily calibration jumps
(Courtesy: X. Dumusque)
New pipeline resolves this. Data releases will be under new pipeline.Annelies Mortier Sun-as-a-star 30 / 51
![Page 38: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/38.jpg)
Does the data containa solar rotational signal?
Annelies Mortier Sun-as-a-star 31 / 51
![Page 39: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/39.jpg)
Solar RVs for ∼ 3 years - binned per day
(Data: Collier Cameron, Mortier et al. 2019. BGLS periodogram: Mortier et al. 2015)
Annelies Mortier Sun-as-a-star 32 / 51
![Page 40: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/40.jpg)
Solar rotation
Solar rotation at ∼ 28 daysand its harmonic at ∼ 13 days
clearly visible and unstable over time.
(Data: Collier Cameron, Mortier et al. 2019. Stacking periodograms: Mortier et al. 2015, 2017)
Annelies Mortier Sun-as-a-star 33 / 51
![Page 41: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/41.jpg)
Data split in semesters
Strongest periodicity and its strength highly variable.
Annelies Mortier Sun-as-a-star 34 / 51
![Page 42: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/42.jpg)
Data split in semesters
Strongest periodicity and its strength highly variable.
Annelies Mortier Sun-as-a-star 35 / 51
![Page 43: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/43.jpg)
What about ouractivity indicators?
Annelies Mortier Sun-as-a-star 36 / 51
![Page 44: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/44.jpg)
RV and FWHM show similar periodicity behaviour
(using data from Collier Cameron, Mortier et al. 2019)
Annelies Mortier Sun-as-a-star 37 / 51
![Page 45: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/45.jpg)
Similar periodicity behaviour - no correlation?
(using data from Collier Cameron, Mortier et al. 2019)Annelies Mortier Sun-as-a-star 38 / 51
![Page 46: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/46.jpg)
Time lag between RV, FWHM, BIS, ...
-10 -5 0 5 10-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
Time Lag (days)
DiscreteCFRV-BIS,FWHM
(Collier Cameron, Mortier et al. 2019)
Temporal offset between RV, FWHM, BIS weakens their correlation.
Annelies Mortier Sun-as-a-star 39 / 51
![Page 47: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/47.jpg)
Let’s use all the data - including solar minimum
(using the full 5 years of HARPS-N solar data)
Annelies Mortier Sun-as-a-star 40 / 51
![Page 48: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/48.jpg)
Is there an additional time dependence?
(using the full 5 years of HARPS-N solar data)Annelies Mortier Sun-as-a-star 41 / 51
![Page 49: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/49.jpg)
Correlation gets weaker with Sun going in Solar minimum
(done by James Hazzard - using 4.5yr of HARPS-N solar data)
With Sun going firmly into solar minimum,correlations get weaker or even disappear.
Annelies Mortier Sun-as-a-star 42 / 51
![Page 50: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/50.jpg)
Daily binning to control granulation
(done by James Hazzard - using 4.5yr of HARPS-N solar data)
Binning densely sampled data, helps to strengthen rotationally-modulatedcorrelations. Caveat: can we get this sampling for stars?
Annelies Mortier Sun-as-a-star 43 / 51
![Page 51: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/51.jpg)
No known optical activity indicators are perfect
(Maldonado et al. 2019)
Annelies Mortier Sun-as-a-star 44 / 51
![Page 52: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/52.jpg)
What about photometry?
Annelies Mortier Sun-as-a-star 45 / 51
![Page 53: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/53.jpg)
Periodograms often do not determine rotation period
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 1
EMPIRESORCEHARPS-N RVs
HARPS-N CCFHARPS-N BIS
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 2
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 3
101 102
Period (days)
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 4
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 1
EMPIRESORCEHARPS-N RVs
HARPS-N CCFHARPS-N BIS
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 2
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 3
101 102
Period (days)
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 4
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 1
EMPIRESORCEHARPS-N RVs
HARPS-N CCFHARPS-N BIS
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 2
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 3
101 102
Period (days)
0.0
0.1
0.2
0.3
Lom
b-Sc
argl
e Po
wer Year 4
(Kosiarek & Crossfield 2020)
Quasiperiodic nature of stellar variability and sparse sampling causetrouble for periodogram or ACF approach. See also Nava et al. 2020.
Annelies Mortier Sun-as-a-star 46 / 51
![Page 54: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/54.jpg)
Using GPs much better, still not optimal (see also talk Vinesh Rajpaul)
0
1
2
3
Am
plit
ud
e
1(W
m2,
ms
1)
SORCE HARPS-N RVs HARPS-N FWHM HARPS-N BIS
0
25
50
75
100
Evolu
tionary
Tim
esc
ale
2
(days)
20
40
Recu
rrence
Tim
esc
ale
3
(days)
1 2 3 4Year
0.2
0.4
0.6
0.8
Leng
thsc
ale
4
(Kosiarek & Crossfield 2020)
Photometry can be helpful, but does not always trace the same variability.
Annelies Mortier Sun-as-a-star 47 / 51
![Page 55: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/55.jpg)
Smallest active regions do not matter for RVs
Annelies Mortier Sun-as-a-star 48 / 51
![Page 56: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/56.jpg)
Lessons learned from Sun-as-a-star observations
The Sun is the only star we’ll ever be sure has no planets ”in the data”Observing the Sun-as-a-star requires more careful data processing, butit can also help to improve the instrument and pipelineSuppression of convective blueshift is the main source of RV variationsEven in solar minimum, variations extend 1m/sMagnetic flux density traces RV variations bestTraditional activity indicators show weakened correlation with RVNo known simultaneous activity indicator trace the RV variations wellBinning densely sampled data improves correlations→ granulation not traced by indicators?Simultaneous photometry can help, when analysed carefully with GPsLarge bright magnetic regions dominate RV variations
Annelies Mortier Sun-as-a-star 49 / 51
![Page 57: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/57.jpg)
To know/find the planet is to know its star
Studying the Sun-as-a-star helps us understand activity-induced RVvariations, allows us to test models, theories, and algorithms.
It is the way forward to detecting a true Earth twin.
Annelies Mortier Sun-as-a-star 50 / 51
![Page 58: Lessons from ”Sun-as-a-star” observations€¦ · The Sun is the only star we know that has no orbiting planets... Because we can remove them from the data. Annelies Mortier Sun-as-a-star](https://reader035.vdocuments.mx/reader035/viewer/2022070917/5fb7c1bd14e738420c7d8201/html5/thumbnails/58.jpg)
Annelies Mortier Sun-as-a-star 51 / 51