Abstract
The quest for Earth-like, extrasolar planets (exoplanets), especially those located inside the habitable zone of their host stars, requires techniques sensitive enough to detect the faint signals produced by those planets. The radial velocity (RV) and photometric transit methods are the most widely used and also the most efficient methods for detecting and characterizing exoplanets. However, presence of astrophysical “noise” makes it difficult to detect and accurately characterize exoplanets. It is important to note that the amplitude of such astrophysical noise is larger than both the signal of Earth-like exoplanets and state-of-the-art instrumentation limit precision, making this a pressing topic that needs to be addressed. In this chapter, I present a general review of the main sources of noise in photometric and RV observations, namely, stellar oscillations, granulation, and magnetic activity. Moreover, for each noise source I discuss the techniques and observational strategies which allow us to mitigate their impact.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
Notes
- 1.
- 2.
Granulation patterns at the surfaces of stars can only be observed through the analysis of spatially-resolved images, which are currently only possible for the Sun.
- 3.
Depending on the latitude of active regions and the stellar differential rotation, different active regions would induce different periodicities.
- 4.
A precision of 0. 5 m s−1 was achieved by the HARPS spectrograph, which enabled the detection of signals due to low-mass/Earth-size planets.
- 5.
BIS = V high − V low, where V high and V low are the velocity average of the points at the top and bottom of the CCF profile, respectively.
- 6.
V span = RV high − RV low, where RV high and RV low are Gaussian fits to the upper and lower parts of the CCF, respectively.
- 7.
V asy estimates the unbalance between the red and blue wings of the CCF.
- 8.
This approach consists in fitting a Gaussian with wings characterized by two different values of the HWHM (half width at half maximum) to the CCF.
- 9.
The S-index is based on the measurement of the emission in the cores of the Ca II H and K lines, and reflects the non-thermal chromospheric heating associated with the magnetic field.
- 10.
log(R HK ′) is closely related to the S-index, giving the emission in the narrow bands normalized by the bolometric brightness of the star.
- 11.
For instance, a stellar spot’s temperature contrast and filling factor are strongly degenerate, and cannot thus be estimated independently.
References
Aigrain, S., Pont, F., Zucker, S.: Mon. Not. R. Astron. Soc. 419, 3147 (2012)
Barclay, T., Rowe, J.F., Lissauer, J.J., et al.: Nature 494, 452 (2013)
Barros, S.C.C., Almenara, J.M., Deleuil, M., et al.: Astron. Astrophys. 569, A74 (2014)
Basri, G., Walkowicz, L.M., Reiners, A.: Astrophys. J. 769, 37 (2013)
Bazot, M., Bouchy, F., Kjeldsen, H., et al.: Astron. Astrophys. 470, 295 (2007)
Béky, B., Kipping, D.M., Holman, M.J.: Mon. Not. R. Astron. Soc. 442, 3686 (2014)
Boisse, I., Moutou, C., Vidal-Madjar, A., et al.: Astron. Astrophys. 495, 959 (2009)
Boisse, I., Bouchy, F., Hébrard, G., et al.: Astron. Astrophys. 528, A4 (2011)
Boisse, I., Bonfils, X., Santos, N.C.: Astron. Astrophys. 545, A109 (2012)
Bonfils, X., Mayor, M., Delfosse, X., et al.: Astron. Astrophys. 474, 293 (2007)
Borucki, W.J., Koch, D., Basri, G., et al.: Science 327, 977 (2010)
Boué, G., Oshagh, M., Montalto, M., Santos, N.C.: Mon. Not. R. Astron. Soc. 422, L57 (2012)
Carter, J.A., Agol, E., Chaplin, W.J., et al.: Science 337, 556 (2012)
Christensen-Dalsgaard, J.: ArXiv e-prints, arXiv:1602.06838 (2016)
Czesla, S., Huber, K.F., Wolter, U., Schröter, S., Schmitt, J.H.M.M.: Astron. Astrophys. 505, 1277 (2009)
Dumusque, X., Udry, S., Lovis, C., Santos, N.C., Monteiro, M.J.P.F.G.: Astron. Astrophys. 525, A140 (2011)
Dumusque, X., Pepe, F., Lovis, C., et al.: Nature 491, 207 (2012)
Dumusque, X., Boisse, I., Santos, N.C.: Astrophys. J., 796, 132 (2014)
Dumusque, X., Glenday, A., Phillips, D.F., et al.: Astrophys. J. 814, L21 (2015)
Faria, J.P., Haywood, R.D., Brewer, B.J., et al.: Astron. Astrophys. 588, A31 (2016)
Ferraz-Mello, S., Tadeu Dos Santos, M., Beaugé, C., Michtchenko, T.A., Rodríguez, A.: Astron. Astrophys. 531, A161 (2011)
Figueira, P., Santos, N.C., Pepe, F., Lovis, C., Nardetto, N.: Astron. Astrophys. 557, A93 (2013)
Gilliland, R.L., Chaplin, W.J., Dunham, E.W., et al.: Astrophys. J. Suppl. Ser. 197, 6 (2011)
Harvey, J.: In: Rolfe, E., Battrick, B. (eds.) Future Missions in Solar, Heliospheric and Space Plasma Physics. ESA Special Publication, vol. 235. European Space Agency, Paris (1985)
Hatzes, A.P., Cochran, W.D.: Mon. Not. R. Astron. Soc. 304, 109 (1999)
Hatzes, A.P., Dvorak, R., Wuchterl, G., et al.: Astron. Astrophys. 520, A93 (2010)
Hatzes, A.P., Fridlund, M., Nachmani, G., et al.: Astrophys. J. 743, 75 (2011)
Haywood, R.D., Collier Cameron, A., Queloz, D., et al.: Mon. Not. R. Astron. Soc. 443, 2517 (2014)
Herrero, E., Ribas, I., Jordi, C., et al.: Astron. Astrophys. 586, A131 (2016)
Jenkins, J.M.: Astrophys. J. 575, 493 (2002)
Kipping, D.M.: Mon. Not. R. Astron. Soc. 427, 2487 (2012)
Mayor, M., Queloz, D.: Nature 378, 355 (1995)
Meunier, N., Desort, M., Lagrange, A.-M.: Astron. Astrophys. 512, A39 (2010)
Noyes, R.W., Hartmann, L.W., Baliunas, S.L., Duncan, D.K., Vaughan, A.H.: Astrophys. J. 279, 763 (1984)
Oshagh, M., Boisse, I., Boué, G., et al.: Astron. Astrophys. 549, A35 (2013a)
Oshagh, M., Santos, N.C., Boisse, I., et al.: Astron. Astrophys. 556, A19 (2013b)
Oshagh, M., Santos, N.C., Ehrenreich, D., et al.: Astron. Astrophys. 568, A99 (2014)
Oshagh, M., Santos, N.C., Figueira, P., et al.: Astron. Astrophys. 583, L1 (2015a)
Oshagh, M., C., S. N., Boisse, I., et al.: in European Physical Journal Web of Conferences, Vol. 101, European Physical Journal Web of Conferences, 05003 (2015b)
Oshagh, M., Dreizler, S., Santos, N.C., Figueira, P., Reiners, A.: Astron. Astrophys. 593, A25 (2016)
Pont, F., Aigrain, S., Zucker, S.: Mon. Not. R. Astron. Soc. 411, 1953 (2011)
Queloz, D., Henry, G.W., Sivan, J.P., et al.: Astron. Astrophys. 379, 279 (2001)
Queloz, D., Bouchy, F., Moutou, C., et al.: Astron. Astrophys. 506, 303 (2009)
Reiners, A.: Living Rev. Sol. Phys. 9, 1 (2012)
Saar, S.H., Donahue, R.A.: Astrophys. J. 485, 319 (1997)
Santos, N.C., Mayor, M., Bouchy, F., et al.: Astron. Astrophys. 474, 647 (2007)
Santos, N.C., Mayor, M., Naef, D., et al.: Astron. Astrophys. 361, 265 (2000)
Santos, N.C., Mayor, M., Naef, D., et al.: Astron. Astrophys. 392, 215 (2002)
Strassmeier, K.G., Rice, J.B., Wehlau, W.H., et al.: Astron. Astrophys. 247, 130 (1991)
Tuomi, M., Anglada-Escude, G., Jenkins, J.S., Jones, H.R.A.: ArXiv e-prints, arXiv:1405.2016 (2014)
Wilson, O.C.: Astrophys. J. 226, 379 (1978)
Acknowledgements
I would like to thank the members of the SOC for inviting me to the IV th Azores International Advanced School in Space Sciences held in the Azores Islands, Portugal. I acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation): OS 508/1-1.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer International Publishing AG
About this paper
Cite this paper
Oshagh, M. (2018). Noise Sources in Photometry and Radial Velocities. In: Campante, T., Santos, N., Monteiro, M. (eds) Asteroseismology and Exoplanets: Listening to the Stars and Searching for New Worlds. Astrophysics and Space Science Proceedings, vol 49. Springer, Cham. https://doi.org/10.1007/978-3-319-59315-9_13
Download citation
DOI: https://doi.org/10.1007/978-3-319-59315-9_13
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-59314-2
Online ISBN: 978-3-319-59315-9
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)