No planet for HD 166435

“…we began a campaign of highprecision photometric observations with an automatic photoelectric telescope (APT) at Fairborn Observatory in Arizona to search for planetary transits and made tentative plans to announce the new planet at the Protostars and Planets IV conference (Mannings et al. 2000).”

“This phenomena is observed on the Sun to a lesser degree where leader spots tend to be larger and to live longer than follower spots, resulting in a displacement up to 5 0 between the photocenters of the spot and the associated plages (Dobson-Hockey & Radick 1986).”

“From 1998 June to 1998 August, 141 Ca II H and K measurements were made on 20 nights with the 100-inch telescope at Mount Wilson Observatory as part of the HK Project (Baliunas et al. 1998).”

“In addition to the stellar radial velocity, the cross-correlation function (CCF) provides additional information about features in the averaged spectral lines (see Queloz 1994 for a review).”

“…for more details), whereas from the DRS, 3 http://archive.eso.org/wdb/wdb/adp/phase3 main/form we obtained the cross-correlation function (CCF), full width half maximum FWHM, the CCF Bisector slope (BIS), and contrast (CON), which are important stellar activity indices (e.g. Queloz et al. 2001).”

“S R ] 2 3 A ug 2 02 1 Donahue, 1997), producing noise or mimicking radial velocity variations due to a planet and therefore resulting in erroneous detections (e.g., Huélamo et al., 2008; Huerta, Johns-Krull, Prato, Hartigan, & Jaffe, 2008; Queloz et al., 2001).”

“…al. 2013; Rajpaul et al. 2015; Delisle et al. 2018), as well as use alternative forms of the cross-correlation method to correct for activity (e.g., Queloz et al. 2001; Simola et al. 2019), these have had limited success in disentangling it from a true Doppler shift at RV’s below 1 m s−1 (Dumusque…”

“Planet search teams benefit from being able to calculate line bisector inverse slopes (BIS, Dravins 1987; Toner & Gray 1988; Queloz et al. 2001) in the region where the radial velocities were calculated with iodine, or have access to additional activity sensitive lines to use in their analysis,…”

“The bisector velocity span (or simply bisector span) is a measurement of the CCF asymmetry computed from the CCF bisector (which is the set of midpoints between the two sides of a CCF profile) at the top and bottom of the CCF profile (e.g., Queloz et al. 2001).”

“From the CCF function we also calculated the bisector as described in Queloz et al. (2001).”

“To assess the line shape evolution, we calculate the velocity span (as introduced, e.g. by Gray 1982; Queloz et al. 2001) Vs, given by Vt − Vb, where Vt and Vb are, respectively, the average velocity at the top and bottom part of the bisector.”

“They may also give false 388 candidates, if they produce a stable periodic signal (e.g. Queloz et al. 2001, Huélamo et al. 2008, Figueira et al. 2010).”

“They may also give false candidates, if they produce a stable periodic signal (e.g. Queloz et al. 2001).”

“The first case, when the BVS measurements were used to withdraw a hypothesis of a low-mass planet, was HD 166435 (Queloz et al. 2001).”

“[65] Queloz, D.”

“The bisector analysis is important for two reasons: – the RV of a star is defined to be the velocity of the center of mass of the star along our line of sight (Queloz et al, 2001).”

“The most widely used of these is the bisector inverse span (BIS), popularized in the context of exoplanet detection by Queloz et al. (2001).”

“For example, a spot on the approaching hemisphere reduces the number of photons received from that hemisphere and, accordingly, its contribution to the stellar line profile ( S. H. Saar & R. A. Donahue 1997; D. Queloz et al. 2001 ) .”

“However, the identification of low-amplitude Doppler signals is persistently challenged by the intrinsic magnetic activity of the host star (Queloz et al. , 2001).”

“We calculated the bisector ( D. F. Gray 1982 ) and associated bisector inverse span ( BIS; D. Queloz et al. 2001 ) for each RV cog -corrected LSD Stokes I profile.”

“…RV amplitude of asteroseismic stellar jitter is on the order of meters per second for Sun-like stars, which can be significant when compared to the RV signals produced by Earth-like planets around 10 cm s − 1 ( e.g., D. Queloz et al. 2001; N. C. Santos et al. 2002; X. Dumusque et al. 2011b ) .”

“The resulting LBS measurement is conceptually analogous to the bisector inverse span (BIS; Queloz et al. 2001), which is commonly used to quantify asymmetry in the cross-correlation function (CCF) between a stellar spectrum and a absorption line mask.”

“Activity indicators, including H α (Bonfils et al. 2007; Robertson et al. 2014; San-tos et al. 2014; Collier Cameron et al. 2019), log R HK (Noyes et al. 1984), and the Bisector Inverse Slope Span (BIS) (Queloz et al. 2001), have also been employed to track and decorrelate activity-induced RV shifts.”

“They concluded that the CRX is as efficient as the line bisector (Queloz et al. 2001) 2021) (and also Lisogorskyi et al. 2019) has exploited the wavelength dependence of RV induced by stellar activity to separate RVs with dynamical origin from stellar activity induced variability.”

“Such spots interfere with RV detection of exoplanets because they affect the measured RV signal from the star, creating false RV readings called ‘jitter’ which can mimic or drown out planetary signals (see Queloz et al. 2001).”

“These starspots can also show similar spectral effects as the stellar radial velocity caused by orbiting planets, introducing so-called radial velocity ‘jitter’, which at times can make it difficult to distinguish between planets and activity signatures (see, e.g., Queloz et al. 2001).”

“For active stars, this type of intrinsic variability can mimic the radial-velocity signature of a short-period planet (e.g. Queloz et al. 2001).”

“Formally the BC is the difference between the span and the midpoint at half height of the CCF [Queloz et al., 2001],”