Another argument against planetary influence on solar activity bites the dust

In the at times bad tempered thread on WUWT  six weeks ago covering Cornelis  de Jager and Dirk Callebaut’s paper “The influence of planetary attractions on the solar tachocline” which attempted to dismiss the possibility of planetary tidal effects on solar activity we were assured by Leif Svalgaard that:

 Unfortunately no effects on planets around other stars on stellar activity have yet been found. See the final slides ofhttp://www.leif.org/research/AGU%20Fall%202011%20SH34B-08.pdf
But this research is still ongoing, so perhaps one day we will get the final proof/disproff (sic) of this…

Leif went on to say:

 althoung (sic) I have already gotten arguments from various sides that our solar system is unique in just the right combination of planets, etc, and that therefore only in our system will the planets drive solar activity. So strong is the belief in the planetary hypothesis than it, almost by definition, becomes impossible to falsify. Go figure…

This is fairly typical of the rhetorical technique Leif Svalgaard uses to try to discredit our line of research, and does him little credit in my opinion. Be that as it may, it now turns out that he doesn’t know his own field as well as he thinks he does.

Nicola Scafetta has drawn my attention to a paper by Gurdemir et al which draws on research going back to the turn of the millenium. The paper discusses planetary induced variation in the host star’s chromosphere first directly observed in 2003 in various wavelengths. Here’s the cite and abstract:

Planet-Induced Emission Enhancements in HD 179949: Results from McDonald Observations

L. Gurdemir ^A, S. Redfield ^B and M. Cuntz ^A C

^A Department of Physics, University of Texas at Arlington, Arlington, TX 76019, USA
^B Astronomy Department, Van Vleck Observatory, Wesleyan University, Middletown, CT 06459, USA
^C Corresponding author.

Australian Journal of Chemistry – http://dx.doi.org/10.1071/AS11074
Submitted: 17 December 2011  Accepted: 16 February 2012   Published online: 2 April 2012

Abstract

We monitored the Ca_II H and K lines of HD 179949, a notable star in the southern hemisphere, to observe and confirm previously identified planet induced emission (PIE) as an effect of star–planet interaction. We obtained high resolution spectra (R ~ 53 000) with a signal-to-noise ratio S/N>  50 in the Ca_II H and K cores during 10 nights of observation at the McDonald Observatory. Wide-band echelle spectra were taken using the 2.7-m telescope. Detailed statistical analysis of Ca_II K revealed fluctuations in the Ca_II K core attributable to planet induced chromospheric emission. This result is consistent with previous studies by Shkolnik et al. (2003). Additionally, we were able to confirm the reality and temporal evolution of the phase shift of the maximum of star–planet interaction previously found. However, no identifiable fluctuations were detected in the Ca_II  H core. The Al_I λ3944 Å line was also monitored to gauge if the expected activity enhancements are confined to the chromospheric layer. Our observations revealed some variability, which is apparently unassociated with planet-induced activity.

Keywords: planet-star interactions — radiation mechanisms: nonthermal — stars: activity — stars: chromospheres — stars: individual (HD 179949) — stars: late-type

The full paper is available here.

A couple of quotes:

“interaction between the planet and stellar atmospheric structure has been identified
that is often broadly classified as “planet-induced (stellar) emission” (PIE). The reality of this phenomenon
has been proposed by Cuntz et al. (2000)”

“The PIE effect was subsequently discovered by Shkolnik et al. (2003) in regard to the HD 179949 system using highresolution (R = 110, 000) and high signal-to-noise ratio spectra based on three observing runs at the CanadaFrance-Hawaii Telescope (CFHT). They also concluded that the PIE effect is expected to be magnetic in nature rather than caused by gravitational star-planet interaction.”

“This latter finding is consistent with the interpretation that the PIE effect is due to magnetic star-planet interaction presumably facilitated along the Parker spiral of the stellar wind.”

.

“Subsequent work was pursued by Shkolnik et al. (2005), Shkolnik et al. (2008) and others, resulting in the identification of the PIE effect in at least six systems, which are: HD 209458, υ And, τ Boo, HD 179949, HD 189733, and HD 73526. The latter study also provides evidence of the on/off nature of the PIE effect, also previously found in the υ And system (Shkolnik et al. 2008), which according to the authors is likely attributable to the changing stellar magnetic field structure throughout the stellar activity cycle (e.g. Lanza 2010). An alternative or supplementary explanation of the significant time dependent variations of the PIE phenomena refers to the flare-type nature of the interaction (e.g. Saar et al. 2004; McIvor et al. 2006).”

.
Nicola Scafetta’s recent paper disposed of Leif Svalgaard and Callebaut & de Jager’s objections based on the small size of the vertical tides induced by the planets. Now Gurdemir et al have disposed of Leif’s incorrect assertion that planetary effects from large exoplanets close to host stars haven’t been observed. I wonder how many more of his erroneous arguments we’ll have to deal with before large numbers of people start to realise that there is a very strong possibility stellar activity is modulated by planetary motion and interaction in our own solar system.