text: 57,29,864823902819823616,3716338821,Mikko Tuomi,"New paper: ""Evidence for at least three planet candidates orbiting #HD20794"". <LINK> ""We also find a significant signal at a period of about 330 d corresponding to a super-Earth or Neptune in the habitable zone."" There is tentative evidence for as many as 6 planets orbiting #HD20794 but the interpretation of these signals is difficult. <LINK> It is now possible to detect signals with amplitudes of only 40cm/s - a factor of 4 in excess that required for detection of Earth analogs. The data reduction and modelling approach applied to HARPS data of #HD20794 explained. <LINK> The paper also applies the ""moving periodogram"", enabling studying the time-invariance of signals. <LINK> <LINK> Demonstrating time-invariance is a key when finding Doppler signals of planets - stellar activity will always vary as a function of time.",https://arxiv.org/abs/1705.05124,"We explore the feasibility of detecting Earth analogs around Sun-like stars using the radial velocity method by investigating one of the largest radial velocities datasets for the one of the most stable radial-velocity stars HD20794. We proceed by disentangling the Keplerian signals from correlated noise and activity-induced variability. We diagnose the noise using the differences between radial velocities measured at different wavelength ranges, so-called ""differential radial velocities"". We apply this method to the radial velocities measured by HARPS, and identify four signals at 18, 89, 147 and 330 d. The two signals at periods of 18 and 89 d are previously reported and are better quantified in this work. The signal at a period of about 147 d is reported for the first time, and corresponds to a super-Earth with a minimum mass of 4.59 Earth mass located 0.51 AU from HD20794. We also find a significant signal at a period of about 330 d corresponding to a super-Earth or Neptune in the habitable zone. Since this signal is close to the annual sampling period and significant periodogram power in some noise proxies are found close to this signal, further observations and analyses are required to confirm it. The analyses of the eccentricity and consistency of signals provide weak evidence for the existence of the previously reported 43 d signal and a new signal at a period of about 11.9 d with a semi amplitude of 0.4 m/s. We find that the detection of a number of signals with radial velocity variations around 0.5\,m/s likely caused by low mass planet candidates demonstrates the important role of noise modeling in searching for Earth analogs. ",Evidence for at least three planet candidates orbiting HD20794,7,"['New paper: ""Evidence for at least three planet candidates orbiting #HD20794"". <LINK>', '""We also find a significant signal at a period of about 330 d corresponding to a super-Earth or Neptune in the habitable zone.""', 'There is tentative evidence for as many as 6 planets orbiting #HD20794 but the interpretation of these signals is difficult. https://t.co/NnLzG4Io0O', 'It is now possible to detect signals with amplitudes of only 40cm/s - a factor of 4 in excess that required for detection of Earth analogs.', 'The data reduction and modelling approach applied to HARPS data of #HD20794 explained. https://t.co/435JH9FqjJ', 'The paper also applies the ""moving periodogram"", enabling studying the time-invariance of signals. https://t.co/EaM1D1qlVO https://t.co/h5WQkMvIdM', 'Demonstrating time-invariance is a key when finding Doppler signals of planets - stellar activity will always vary as a function of time.']",17,05,829