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Amateur astronomers can make useful contributions to the study of comets. They add temporal coverage and multi-scale observations which can aid the study of fast-changing, and large-scale comet features. We document and review the amateur observing campaign set up to complement the Rosetta space mission, including the data submitted to date, and consider the campaigns effectiveness in the light of experience from previous comet amateur campaigns. We report the results of surveys of campaign participants, the amateur astronomy community, and schools who participated in a comet 46P observing campaign. We draw lessons for future campaigns which include the need for: clarity of objectives; recognising the wider impact campaigns can have on increasing science capital; clear, consistent, timely and tailored guidance; easy upload procedures with in-built quality control; and, regular communication, feedback and recognition.
We present a summary of the campaign of remote observations that supported the European Space Agencys Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from before Rosettas arrival until nearly the end of mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft, and a way to directly compare 67P with other comets. The observations revealed 67P to be a relatively `well behaved comet, typical of Jupiter family comets and with activity patterns that repeat from orbit-to-orbit. Comparison between this large collection of telescopic observations and the in situ results from Rosetta will allow us to better understand comet coma chemistry and structure. This work is just beginning as the mission ends -- in this paper we present a summary of the ground-based observations and early results, and point to many questions that will be addressed in future studies.
In this white paper, we present a cross-section of important scientific questions that remain partially or completely unanswered, ranging from Titan exosphere to the deep interior, and we detail which instrumentation and mission scenarios should be used to answer them. Our intention is to formulate the science goals for the next generation of planetary missions to Titan in order to prepare the future exploration of the moon. The ESA L-class mission concept that we propose is composed of a Titan orbiter and at least an in situ element (lake lander and/or drone(s)).
We present observations of comet 67P/Churyumov-Gerasimenko acquired in support of the $Rosetta$ mission. We obtained usable data on 68 nights from 2014 September until 2016 May, with data acquired regularly whenever the comet was observable. We collected an extensive set of near-IR $J$, $H$, and $Ks$ data throughout the apparition plus visible-light images in $g$, $r$, $i$, and $z$ when the comet was fainter. We also obtained broadband $R$ and narrowband $CN$ filter observations when the comet was brightest using telescopes at Lowell Observatory. The appearance was dominated by a central condensation and the tail until 2015 June. From 2015 August onwards there were clear asymmetries in the coma, which enhancements revealed to be due to the presence of up to three features (i.e., jets). The features were similar in all broadband filters; $CN$ images did not show these features but were instead broadly enhanced in the southeastern hemisphere. Modeling using the parameters from Vincent et al. (2013) replicated the dust morphology reasonably well, indicating that the pole orientation and locations of active areas have been relatively unchanged over at least the last three apparitions. The dust production, as measured by $A(0^{circ})f{rho}$ peaked $sim$30 days after perihelion and was consistent with predictions from previous apparitions. $A(0^{circ})f{rho}$ as a function of heliocentric distance was well fit by a power-law with slope $-$4.2 from 35-120 days post-perihelion. We detected photometric evidence of apparent outbursts on 2015 August 22 and 2015 September 19, although neither was discernible morphologically in this dataset.
Despite over 50 years of Gamma-Ray Burst (GRB) observations many open questions remain about their nature and the environments in which the emission takes place. Polarization measurements of the GRB prompt emission have long been theorized to be able to answer most of these questions. The POLAR detector was a dedicated GRB polarimeter developed by a Swiss, Chinese and Polish collaboration. The instrument was launched, together with the second Chinese Space Lab, the Tiangong-2, in September 2016 after which it took 6 months of scientific data. During this period POLAR detected 55 GRBs as well as several pulsars. From the analysis of the GRB polarization catalog we see that the prompt emission is lowly polarized or fully unpolarized. There is, however, the caveat that within single pulses there are strong hints of an evolving polarization angle which washes out the polarization degree in the time integrated analysis. Building on the success of the POLAR mission, the POLAR-2 instrument is currently under development. POLAR-2 is a Swiss, Chinese, Polish and German collaboration and was recently approved for launch in 2024. Thanks to its large sensitivity POLAR-2 will produce polarization measurements of at least 50 GRBs per year with a precision equal or higher than the best results published by POLAR. POLAR-2 thereby aims to make the prompt polarization a standard observable and produce catalogs of the gamma-ray polarization of GRBs. Here we will present an overview of the POLAR mission and all its scientific measurement results. Additionally, we will present an overview of the future POLAR-2 mission, and how it will answer some of the questions raised by the POLAR results.
NEID is a high-resolution optical spectrograph on the WIYN 3.5-m telescope at Kitt Peak National Observatory and will soon join the new generation of extreme precision radial velocity instruments in operation around the world. We plan to use the instrument to conduct the NEID Earth Twin Survey (NETS) over the course of the next 5 years, collecting hundreds of observations of some of the nearest and brightest stars in an effort to probe the regime of Earth-mass exoplanets. Even if we take advantage of the extreme instrumental precision conferred by NEID, it will remain difficult to disentangle the weak (~10 cm s$^{-1}$) signals induced by such low-mass, long-period exoplanets from stellar noise for all but the quietest host stars. In this work, we present a set of quantitative selection metrics which we use to identify an initial NETS target list consisting of stars conducive to the detection of exoplanets in the regime of interest. We also outline a set of observing strategies with which we aim to mitigate uncertainty contributions from intrinsic stellar variability and other sources of noise.