Abstract
The presence of starspots , faculae and granulation on the photosphere of a star induces quasi-periodic signals that can conceal and even mimic the Doppler signature of orbiting planets. This has resulted in several false detections (see Queloz et al. 2001; Bonfils et al. 2007; Huélamo et al. 2008; Boisse et al. 2009, 2011; Gregory 2011; Haywood et al. 2014; Santos et al. 2014; Robertson et al. 2014 and many others). Understanding the RV signatures of stellar activity, in particular those modulated by the stellar rotation, is essential to develop the next generation of more sophisticated activity models and further improve our ability to detect and characterise low-mass planets. The Sun is the only star whose surface can be directly resolved at high resolution, and therefore constitutes an excellent test case to explore the physical origin of stellar radial-velocity variability. In this chapter, I present HARPS observations of sunlight scattered off the bright asteroid 4/Vesta, from which I deduced the Sun’s activity-driven RV variations. In parallel, the HMI instrument onboard the Solar Dynamics Observatory provided me with simultaneous high spatial resolution magnetograms, dopplergrams, and continuum images of the Sun. I determined the RV modulation arising from the suppression of granular blueshift by magnetically active regions (sunspots and faculae) and the flux imbalance induced by dark spots. I confirm that the inhibition of convection is the dominant source of activity-induced RV variations at play. Finally, I find that the activity-driven RV variations of the Sun are strongly correlated with its full-disc magnetic flux, which could become a useful proxy for activity-related RV noise in future exoplanet searches.
Keywords
- Solar Dynamics Observatory
- Spacecraft Motion
- Activity Basis Function
- Residual White Noise
- Bright Asteroid
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This chapter uses material from, and is based on, Haywood et al., 2016, MNRAS, 457, 3637.
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- 1.
Solar System Dynamics Group, Horizons On-Line Ephemeris System, 4800 Oak Grove Drive, Jet Propulsion Laboratory, Pasadena, CA 91109 USA—Information: http://ssd.jpl.nasa.gov/, Jon.Giorgini@jpl.nasa.gov.
- 2.
HMI data products can be downloaded online via the Joint Science Operations Center website: http://jsoc.stanford.edu.
- 3.
Source code available at: http://hesperia.gsfc.nasa.gov/ssw/gen/idl/solar/.
References
Allen C (1973) Allen: astrophysical quantities, 3rd edn. The Athlone Press, University of London
Baranne A et al (1996) Astron Astrophys Suppl Ser 119:373
Boisse I, Bouchy F, Hébrard G, Bonfils X, Santos N, Vauclair S (2011) Astron Astrophys 528:A4
Boisse I et al (2009) Astron Astrophys 495:959
Bonfils X et al (2007) Astron Astrophys 474:293
Carrington RC (1859) Month Not R Astron Soc 19:81
Collier Cameron A et al (2006) Month Not R Astron Soc 373:799
Deming D, Espenak F, Jennings DE, Brault JW, Wagner J (1987) Astrophys J 316:771
Deming D, Plymate C (1994) Astrophys J 426:382
Desort M, Lagrange AM, Galland F, Udry S, Mayor M (2007) Astron Astrophys 473:983
Gregory PC (2011) MNRAS 415:2523 1101.0800
Haywood RD et al (2014) Monthly notices of the royal astronomical society. 443(3):2517–2531
Haywood RD et al (2016) arXiv:1601.05651
Huélamo N et al (2008) Astron Astrophys 489:L9
Jiménez A, Pallé PL, Régulo C, Roca Cortes T, Isaak GR (1986) COSPAR and IAU. 6–89
Lagrange AM, Desort M, Meunier N (2010) Astron Astrophys 512:A38
Lanza AF, Molaro P (2015) Experimental astronomy. 39:461. 1505.00918
Lindegren L, Dravins D (2003) Astron Astrophys 401:1185
Lovis C, Pepe F (2007) Astron Astrophys 468:1115
Makarov VV, Beichman CA, Catanzarite JH, Fischer DA, Lebreton J, Malbet F, Shao M (2009) Astrophys J 707:L73
Meunier N, Desort M, Lagrange AM (2010) Astron Astrophys 512:A39
Molaro P, Centurión M (2010) Astron Astrophys 525:A74
McMillan RS, Moore TL, Perry ML, Smith PH (1993) ApJ 403:801–809, doi:10.1086/172251, http://adsabs.harvard.edu/abs/1993ApJ...403..801M
Pesnell WD, Thompson BJ, Chamberlin PC (2012) Sol Phys 275:3
Queloz D et al (2001) Astron Astrophys 379:279
Reiners A, Shulyak D, Anglada-Escudé G, Jeffers SV, Morin J, Zechmeister M, Kochukhov O, Piskunov N (2013) Astron Astrophys 552:103
Robertson P, Mahadevan S, Endl M, Roy A (2014) Science 345:440
Robinson RD Jr (1980) APJ 239:961
Russell CT et al (2012) Science 336:684
Santos NC et al (2014) Astron Astrophys 566:35
Schou J et al (2012) Sol Phys 275:229
Snodgrass HB, Ulrich RK (1990) Astrophys J 351:309
Stephenson CB (1951) Astrophys J 114:500
Thomas PC, Binzel RP, Gaffey MJ, Zellner BH, Storrs AD, Wells E (1997) Icarus 128:88
Thompson WT (2006) Astron Astrophys 449:791
Yeo KL, Solanki SK, Krivova NA (2013) A&A. 550:A95 1302.1442
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Haywood, R.D. (2016). An Exploration into the Radial-Velocity Variability of the Sun. In: Radial-velocity Searches for Planets Around Active Stars. Springer Theses. Springer, Cham. https://doi.org/10.1007/978-3-319-41273-3_5
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