RADIAL VELOCITY PLANETS DE-ALIASED: A NEW, SHORT PERIOD FOR SUPER-EARTH 55 Cnc e

By R. Dawson, D. Fabrycky. 2010

198 citations recorded by the source corpus.

Radial velocity measurements of stellar reflex motion have revealed many extrasolar planets, but gaps in the observations produce aliases, spurious frequencies that are frequently confused with the planets' orbital frequencies. In the case of Gl 581 d, the distinction between an alias and the true frequency was the distinction between a frozen, dead planet and a planet possibly hospitable to life. To improve the characterization of planetary systems, we describe how aliases originate and present a new approach for distinguishing between orbital frequencies and their aliases. Our approach harnesses features in the spectral window function to compare the amplitude and phase of predicted aliases with peaks present in the data. We apply it to confirm prior alias distinctions for the planets GJ 876 d and HD 75898 b. We find that the true periods of Gl 581 d and HD 73526 b/c remain ambiguous. We revise the periods of HD 156668 b and 55 Cnc e, which were afflicted by daily aliases. For HD 156668 b, the correct period is 1.2699 days and the minimum mass is (3.1 ± 0.4) M⊕. For 55 Cnc e, the correct period is 0.7365 days—the shortest of any known planet—and the minimum mass is (8.3 ± 0.3) M⊕. This revision produces a significantly improved five-planet Keplerian fit for 55 Cnc, and a self-consistent dynamical fit describes the data just as well. As radial velocity techniques push to ever-smaller planets, often found in systems of multiple planets, distinguishing true periods from aliases will become increasingly important.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/cba103d3b498e067ab60f056e9377a41ac872ac4

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Citations in the corpus

A dynamically-packed planetary system around GJ 667C with three super-Earths in its habitable zone (2013, methodology): “Using the recipes n Dawson & Fabrycky (2010), it is easy to show that the two peaks are the yearly aliases of each other.”
Limits on Planetary Companions from Doppler Surveys of Nearby Stars (2016, background): “Non-randomly timed clusters of observation times inject period aliases into the periodograms, which can suppress or enhance the detectability at particular periods (Dawson & Fabrycky 2010).”
CHARACTERIZING K2 PLANET DISCOVERIES: A SUPER-EARTH TRANSITING THE BRIGHT K DWARF HIP 116454 (2014, background): “We found a strong peak at a period of 9.1 days and an aliased peak of similar strength with a period close to 1 day, corresponding to the daily sampling alias of the 9.1 day signal (e.g. Dawson & Fabrycky 2010).”
POSSIBLE DISINTEGRATING SHORT-PERIOD SUPER-MERCURY ORBITING KIC 12557548 (2012, background): “E P] 2 4 M ar 2 01 2 measurements (Fischer et al. 2008; Dawson & Fabrycky 2010) and detected in transit by extensive satellite observations with the MOST satellite (Winn et al. 2011).”
A SUPER-EARTH TRANSITING A NAKED-EYE STAR (2011, methodology): “The signal has the predicted period, and the observed epoch is bracketed by the two predicted epochs of Dawson & Fabrycky (2010).”
A STUDY OF THE SHORTEST-PERIOD PLANETS FOUND WITH KEPLER (2014, background): “Among the best known USP planets are 55 Cnc e (Dawson & Fabrycky 2010; Winn et al. 2011; Demory et al. 2011a), CoRoT-7b (Léger et al. 2009; Queloz et al. 2009), and Kepler-10b (Batalha et al. 2011).”
State of the Field: Extreme Precision Radial Velocities (2016, background): “…these aliases and their harmonics produce peaks at positions that can be calculated: falias = |ftrue ± fsample| (7) 91 Presentation by Rebekah Dawson Dawson & Fabrycky (2010) show that aliases imprint a set of predictable peaks; by modeling a noise free data set, it can be possible to confirm…”
The CARMENES Search for Exoplanets around M Dwarfs: A Low-mass Planet in the Temperate Zone of the Nearby K2-18 (2018, background): “Dawson & Fabrycky (2010) showed that the reported periods of 55 Cnc e and HD 156668 b from their respective discovery papers were actually wrong and affected by daily aliases.”
THE HARPS-TERRA PROJECT. I. DESCRIPTION OF THE ALGORITHMS, PERFORMANCE, AND NEW MEASUREMENTS ON A FEW REMARKABLE STARS OBSERVED BY HARPS (2012, background): “This is characteristic of long period signals aliased with the seasonal availability of the star (see Dawson & Fabrycky 2010, for a detailed discussion of the yearly alias).”
The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “The procedure for detangling aliases from orbital frequencies is very sensitive to the time sampling of observations (Dawson & Fabrycky, 2010).”
EXTRACTING RADIAL VELOCITIES OF A- AND B-TYPE STARS FROM ECHELLE SPECTROGRAPH CALIBRATION SPECTRA (2015, background): “Lomb-Scargle analysis of the radial velocity time series for each target often finds spurious short-period signals, due to aliasing, which is particularly troublesome for sparsely sampled targets (Dawson & Fabrycky 2010).”
The HARPS search for southern extra-solar planets - XXVIII. Up to seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems (2010, background): “FAP thresholds of 10%, 1% and 0.1% are indicated as dashed lines. been long known in several fields of astrophysics dealing with ground-based time series analysis, and is also relevant to radial velocity searches for exoplanets (see Dawson & Fabrycky 2010, for a recent overview).”
ARCHITECTURE AND DYNAMICS OF KEPLER'S CANDIDATE MULTIPLE TRANSITING PLANET SYSTEMS (2011, background): “…with moderately low SNR, so period ratios can be confidently determined without the harmonic ambiguities that affect RV detections (Anglada-Escudé et al. 2010; Dawson & Fabrycky 2010); however, transits can be missed or noise can be mistaken for additional transits when the SNR is very low.”
The HARPS search for southern extra-solar planets (2018, methodology): “The signal-to-noise ratio (S/N) and the 43 nights with two points are not sufficient in this case to apply a dealiasing technique such as is described in Dawson & Fabrycky (2010).”
DETECTION OF AN ATMOSPHERE AROUND THE SUPER-EARTH 55 CANCRI E (2015, background): “However Dawson & Fabrycky (2010) revised these values, reporting a period of 0.7365 days and a minimum mass of 8.3 ± 0.3 M⊕.”
THE LICK–CARNEGIE EXOPLANET SURVEY: A 3.1 M⊕ PLANET IN THE HABITABLE ZONE OF THE NEARBY M3V STAR GLIESE 581 (2010, background): “Most recently, Dawson and Fabrycky (2010) published a detailed study of the effects of aliasing on the GJ 581 data set of Mayor09.”
PHOTOCHEMISTRY IN TERRESTRIAL EXOPLANET ATMOSPHERES. I. PHOTOCHEMISTRY MODEL AND BENCHMARK CASES (2012, unknown): “…2005; Udry et al. 2007; Forveille et al. 2009; Léger et al. 2009; Charbonneau et al. 2009; Mayor et al. 2009; Vogt et al. 2010; Rivera et al. 2010; Dawson & Fabrycky 2010; Holman et al. 2010; Howard et al. 2011; Bonfils et al. 2011; Winn et al. 2011; Demory et al. 2011; Batalha et al. 2011;…”