15 research outputs found
The first super-Earth Detection from the High Cadence and High Radial Velocity Precision Dharma Planet Survey
The Dharma Planet Survey (DPS) aims to monitor about 150 nearby very bright
FGKM dwarfs (within 50 pc) during 20162020 for low-mass planet detection and
characterization using the TOU very high resolution optical spectrograph
(R100,000, 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 ( mag) on the sky with a super-Earth
candidate. The planet candidate has a mass of 8.47,
period of d, and eccentricity of . 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 (3944.5 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.Comment: 13 pages, 17 figures, Accepted for publication in MNRA
The first super-Earth detection from the high cadence and high radial velocity precision Dharma Planet Survey
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≈100000, 380–900 nm). 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 8.47 ± 0.47MEarth, period of 42.38 ± 0.01 d, and eccentricity of 0.04+0.05−0.03. This radial velocity (RV) signal was independently detected by Díaz et al., but they could not confirm if the signal is from a planet or 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 modelled 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
27th Annual Invitational Madrigal and Chamber Choir Festival
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Patterns of mortality in free-ranging California Condors (Gymnogyps californianus).
We document causes of death in free-ranging California Condors (Gymnogyps californianus) from the inception of the reintroduction program in 1992 through December 2009 to identify current and historic mortality factors that might interfere with establishment of self-sustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first post-release death) through December 2009, from a maximum population-at-risk of 352 birds, for a cumulative crude mortality rate of 38%. A definitive cause of death was determined for 76 of the 98 submitted cases, 70% (53/76) of which were attributed to anthropogenic causes. Trash ingestion was the most important mortality factor in nestlings (proportional mortality rate [PMR] 73%; 8/11), while lead toxicosis was the most important factor in juveniles (PMR 26%; 13/50) and adults (PMR 67%; 10/15). These results demonstrate that the leading causes of death at all California Condor release sites are anthropogenic. The mortality factors thought to be important in the decline of the historic California Condor population, particularly lead poisoning, remain the most important documented mortality factors today. Without effective mitigation, these factors can be expected to have the same effects on the sustainability of the wild populations as they have in the past
Recommended from our members
Patterns of mortality in free-ranging California Condors (Gymnogyps californianus).
We document causes of death in free-ranging California Condors (Gymnogyps californianus) from the inception of the reintroduction program in 1992 through December 2009 to identify current and historic mortality factors that might interfere with establishment of self-sustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first post-release death) through December 2009, from a maximum population-at-risk of 352 birds, for a cumulative crude mortality rate of 38%. A definitive cause of death was determined for 76 of the 98 submitted cases, 70% (53/76) of which were attributed to anthropogenic causes. Trash ingestion was the most important mortality factor in nestlings (proportional mortality rate [PMR] 73%; 8/11), while lead toxicosis was the most important factor in juveniles (PMR 26%; 13/50) and adults (PMR 67%; 10/15). These results demonstrate that the leading causes of death at all California Condor release sites are anthropogenic. The mortality factors thought to be important in the decline of the historic California Condor population, particularly lead poisoning, remain the most important documented mortality factors today. Without effective mitigation, these factors can be expected to have the same effects on the sustainability of the wild populations as they have in the past