Planet in the 40 Eridani system

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Planet in the 40 Eridani system

Post by Borislav on 21st August 2017, 11:14 am

https://sites.psu.edu/eprv2017/files/2017/03/EPRV_III_Program-2hk96fs.pdf

Matias Diaz
Disentanging doppler signal and stellar activity: the case of HD 26965.

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Re: Planet in the 40 Eridani system

Post by Borislav on 21st August 2017, 11:15 am

minimum mass 8.10 mass Earth
orbital period 42.37 days
data from HIRES, PFS, CHIRON and HARPS over a timespan of 15 years.

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Re: Planet in the 40 Eridani system

Post by Lazarus on 22nd August 2017, 4:42 am

We report the discovery of a radial velocity (RV) signal that could be interpreted as a planet candidate orbiting the bright, metal-poor K dwarf HD26965, with an orbital period of 42.37 days, or alternatively, as the presence of residual, uncorrected rotational activity in the data. We will show why the latter is favored and makes this dataset an excellent test case for building new correlated noise models to remove the effects due to magnetic activity on Doppler measurements.
(emphasis mine)

Not going to get too excited about this one until more data becomes available.
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Re: Planet in the 40 Eridani system

Post by Sirius_Alpha on 19th July 2018, 8:45 pm

The first super-Earth Detection from the High Cadence and High Radial Velocity Precision Dharma Planet Survey
https://arxiv.org/abs/1807.07098

The Dharma Planet Survey (DPS) aims to monitor about 150 nearby very bright FGKM dwarfs (within 50 pc) during 2016−2020 for low-mass planet detection and characterization using the TOU very high resolution optical spectrograph (R≈100,000, 380-900nm). TOU was initially mounted to the 2-m Automatic Spectroscopic Telescope at Fairborn Observatory in 2013-2015 to conduct a pilot survey, then moved to the dedicated 50-inch automatic telescope on Mt. Lemmon in 2016 to launch the survey. Here we report the first planet detection from DPS, a super-Earth candidate orbiting a bright K dwarf star, HD 26965. It is the second brightest star (V=4.4 mag) on the sky with a super-Earth candidate. The planet candidate has a mass of 8.470.47MEarth, period of 42.380.01 d, and eccentricity of 0.04+0.05−0.03. This RV signal was independently detected by Diaz et al. (2018), but they could not confirm if the signal is from a planet or from stellar activity. The orbital period of the planet is close to the rotation period of the star (39−44.5 d) measured from stellar activity indicators. Our high precision photometric campaign and line bisector analysis of this star do not find any significant variations at the orbital period. Stellar RV jitters modeled from star spots and convection inhibition are also not strong enough to explain the RV signal detected. After further comparing RV data from the star's active magnetic phase and quiet magnetic phase, we conclude that the RV signal is due to planetary-reflex motion and not stellar activity.

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Re: Planet in the 40 Eridani system

Post by Lazarus on 25th July 2018, 3:34 pm

Nice update. I wonder how much this world would have been affected by the evolution of 40 Eridani B.
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Re: Planet in the 40 Eridani system

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