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All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Planetary Candidates from K2 Campaign 16

Given that Campaign 16 of the K2 mission is one of just two K2 campaigns observed so far in "forward-facing" mode, which enables immediate follow-up observations from the ground, we present a catalog of interesting targets identified through photometry alone. Our catalog includes 30 high-quality planet candidates (showing no signs of being non-planetary in nature), 48 more ambiguous events that may be either planets or false positives, 164 eclipsing binaries, and 231 other regularly periodic variable sources. We have released light curves for all targets in C16 and have also released system parameters and transit vetting plots for all interesting candidates identified in this paper. Of particular interest is a candidate planet orbiting the bright F dwarf HD 73344 (V = 6.9, K = 5.6) with an orbital period of 15 days. If confirmed, this object would correspond to a 2.56 +/- 0.18 R⊕ planet and would likely be a favorable target for radial velocity characterization. This paper is intended as a rapid release of planet candidates, eclipsing binaries, and other interesting periodic variables to maximize the scientific yield of this campaign, and as a test run for the upcoming TESS mission, whose frequent data releases call for similarly rapid candidate identification and efficient follow up.

bright F dwarf↗
NASA NTRS2017

An Isolated Microlens Observed from K2, Spitzer, and Earth

We present the result of microlensing event MOA-2016-BLG-290, which received observations from the two-wheel Kepler (K2), Spitzer, as well as ground-based observatories. A joint analysis of data from K2 and the ground leads to two degenerate solutions of the lens mass and distance. This degeneracy is effectively broken once the (partial) Spitzer light curve is included. Altogether, the lens is found to be an extremely low-mass star or brown dwarf (77(sup +34)(sub -23) M(sub J)) located in the Galactic bulge (6.8 ± 0.4 kpc). MOA-2016-BLG-290 is the first microlensing event for which we have signals from three well-separated (~1 au) locations. It demonstrates the power of two-satellite microlensing experiment in reducing the ambiguity of lens properties, as pointed out independently by S. Refsdal and A. Gould several decades ago.

microlensing event MOA-2016-BLG-290↗
NASA NTRS2021

Follow-up and Validation of K2 and TESS Planetary Systems with Keck NIRC2 Adaptive Optics Imaging

High resolution imaging (HRI) is a critical part of the transiting exoplanet follow-up and validation process. HRI allows previously unresolved stellar companions and background blends to be resolved, vetting false positive signals and improving the radii measurements of true planets. Through a multi-semester Keck NIRC2 adaptive optics imaging program, we have pursued HRI of K2 and TESS candidate planet host systems to provide the transiting exoplanet community with necessary data for system validation and characterization. Here we present a summary of our ongoing program that includes an up to date list of targets observed, a description of the observations and data reduction, and a discussion of planetary systems validated by the community using these data. This observing program has been key in NASA’s K2 and TESS missions reaching their goals of identifying new exoplanets ideal for continued follow-up observations to measure their masses and investigate their atmospheres. All observations presented here are available as calibrated images and resulting contrast curves through the Exoplanet Follow-up Observing Program (ExoFOP) website. We encourage members of the exoplanet community to use these data products in their ongoing planetary system validation and characterization efforts.

Adaptive optics↗
NASA NTRS2026

The Evolution in Coma Molecular Composition of Comet C/2017 K2 (PanSTARRS) Across the H 2 O Sublimation Zone: ALMA Imaging of an H 2 O-Dominated Coma

We report a survey of molecular emission from cometary volatiles using the Atacama Large Millimeter/Submillimeter Array (ALMA) toward comet C/2017 K2 (PanSTARRS) carried out on UT 2022 September 21, 22, and 23 at a heliocentric distance r H 3 OH, and H 2 CO (along with continuum emission from dust) sampled molecular chemistry in C/2017 K2 at the inner edge of the H 2 O sublimation zone, the region from r H 2 O begins vigorously subliming and increasingly dominating comet activity, discerning parent from daughter or extended source species. This work presents spectrally integrated flux maps, production rates, and parent scale lengths for each molecule. CH 3 OH, CO, and HCN were produced within ~250 km of the nucleus, potentially including contributions from sublimation of icy grains. CS was consistent with production from CS 2 photolysis, and H 2 CO required production from extended sources in the coma. An ortho-to-para ratio of 2.9 ± 0.4 for H 2 CO was derived from simultaneously measured transitions of each spin species. The continuum was extended and spatially resolved, consistent with thermal emission from dust in the coma. Analysis of the continuum visibilities provided an upper limit on the nucleus diameter d <6.6 km and coma dust masses of (1.2-2.4) times10 11 kg.

Nathan X Roth↗
DOE OSTI2020

Materials Data on K2(NbCl3)3 by Materials Project

K2(NbCl3)3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six Cl1- atoms. There are a spread of K–Cl bond distances ranging from 3.09–3.68 Å. There are two inequivalent Nb+2.33+ sites. In the first Nb+2.33+ site, Nb+2.33+ is bonded to five Cl1- atoms to form corner-sharing NbCl5 square pyramids. There are a spread of Nb–Cl bond distances ranging from 2.47–2.65 Å. In the second Nb+2.33+ site, Nb+2.33+ is bonded to five Cl1- atoms to form corner-sharing NbCl5 square pyramids. There are a spread of Nb–Cl bond distances ranging from 2.48–2.60 Å. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 2-coordinate geometry to two Nb+2.33+ atoms. In the second Cl1- site, Cl1- is bonded to three equivalent K1+ and one Nb+2.33+ atom to form a mixture of distorted edge and corner-sharing ClK3Nb tetrahedra. In the third Cl1- site, Cl1- is bonded in a trigonal planar geometry to two equivalent K1+ and one Nb+2.33+ atom. In the fourth Cl1- site, Cl1- is bonded in a 2-coordinate geometry to two equivalent Nb+2.33+ atoms. In the fifth Cl1- site, Cl1- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Nb+2.33+ atoms. In the sixth Cl1- site, Cl1- is bonded in a 3-coordinate geometry to one K1+ and two Nb+2.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Materials Data on K2(CuTe)5 by Materials Project

K2(CuTe)5 is alpha bismuth trifluoride-derived structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. K1+ is bonded in a body-centered cubic geometry to eight Te2- atoms. There are a spread of K–Te bond distances ranging from 3.59–3.78 Å. There are three inequivalent Cu+1.60+ sites. In the first Cu+1.60+ site, Cu+1.60+ is bonded to four Te2- atoms to form a mixture of edge and corner-sharing CuTe4 tetrahedra. There are two shorter (2.57 Å) and two longer (2.60 Å) Cu–Te bond lengths. In the second Cu+1.60+ site, Cu+1.60+ is bonded to four Te2- atoms to form a mixture of edge and corner-sharing CuTe4 tetrahedra. There are two shorter (2.61 Å) and two longer (2.66 Å) Cu–Te bond lengths. In the third Cu+1.60+ site, Cu+1.60+ is bonded to four Te2- atoms to form a mixture of edge and corner-sharing CuTe4 tetrahedra. There are a spread of Cu–Te bond distances ranging from 2.65–2.74 Å. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 8-coordinate geometry to four equivalent K1+ and four Cu+1.60+ atoms. In the second Te2- site, Te2- is bonded in a 8-coordinate geometry to four equivalent K1+ and four Cu+1.60+ atoms. In the third Te2- site, Te2- is bonded in a 6-coordinate geometry to two equivalent K1+ and four Cu+1.60+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(NbBr3)3 by Materials Project

K2(NbBr3)3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six Br1- atoms. There are a spread of K–Br bond distances ranging from 3.25–3.93 Å. There are two inequivalent Nb+2.33+ sites. In the first Nb+2.33+ site, Nb+2.33+ is bonded to five Br1- atoms to form distorted corner-sharing NbBr5 square pyramids. There are a spread of Nb–Br bond distances ranging from 2.61–2.89 Å. In the second Nb+2.33+ site, Nb+2.33+ is bonded to five Br1- atoms to form corner-sharing NbBr5 square pyramids. There are a spread of Nb–Br bond distances ranging from 2.62–2.84 Å. There are six inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 2-coordinate geometry to two equivalent K1+ and two equivalent Nb+2.33+ atoms. In the second Br1- site, Br1- is bonded in a trigonal planar geometry to two equivalent K1+ and one Nb+2.33+ atom. In the third Br1- site, Br1- is bonded to three equivalent K1+ and one Nb+2.33+ atom to form a mixture of edge and corner-sharing BrK3Nb tetrahedra. In the fourth Br1- site, Br1- is bonded in a 2-coordinate geometry to two equivalent Nb+2.33+ atoms. In the fifth Br1- site, Br1- is bonded in a 2-coordinate geometry to two Nb+2.33+ atoms. In the sixth Br1- site, Br1- is bonded in a 3-coordinate geometry to one K1+ and two Nb+2.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(ReSe2)3 by Materials Project

K2(ReSe2)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of K–Se bond distances ranging from 3.30–3.65 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.31–3.62 Å. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of K–Se bond distances ranging from 3.21–3.73 Å. There are three inequivalent Re+3.33+ sites. In the first Re+3.33+ site, Re+3.33+ is bonded to five Se2- atoms to form edge-sharing ReSe5 square pyramids. There are a spread of Re–Se bond distances ranging from 2.54–2.62 Å. In the second Re+3.33+ site, Re+3.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing ReSe5 square pyramids. There are a spread of Re–Se bond distances ranging from 2.52–2.67 Å. In the third Re+3.33+ site, Re+3.33+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing ReSe5 square pyramids. There are a spread of Re–Se bond distances ranging from 2.52–2.67 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to one K1+ and three Re+3.33+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Re+3.33+ atoms. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to two K1+ and three Re+3.33+ atoms. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to three K1+ and three Re+3.33+ atoms. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to three K1+, one Re+3.33+, and one Se2- atom. The Se–Se bond length is 2.47 Å. In the sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to three K1+ and two Re+3.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(TcS2)3 by Materials Project

K2(TcS2)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of K–S bond distances ranging from 3.14–3.54 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of K–S bond distances ranging from 3.17–3.48 Å. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of K–S bond distances ranging from 3.10–3.62 Å. There are three inequivalent Tc+3.33+ sites. In the first Tc+3.33+ site, Tc+3.33+ is bonded to five S2- atoms to form edge-sharing TcS5 square pyramids. There are a spread of Tc–S bond distances ranging from 2.39–2.50 Å. In the second Tc+3.33+ site, Tc+3.33+ is bonded to five S2- atoms to form a mixture of edge and corner-sharing TcS5 square pyramids. There are a spread of Tc–S bond distances ranging from 2.38–2.51 Å. In the third Tc+3.33+ site, Tc+3.33+ is bonded to five S2- atoms to form a mixture of edge and corner-sharing TcS5 square pyramids. There are a spread of Tc–S bond distances ranging from 2.38–2.51 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to one K1+ and three Tc+3.33+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Tc+3.33+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to two K1+ and three Tc+3.33+ atoms. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to three K1+ and three Tc+3.33+ atoms. In the fifth S2- site, S2- is bonded in a 5-coordinate geometry to three K1+, one Tc+3.33+, and one S2- atom. The S–S bond length is 2.12 Å. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to three K1+ and two Tc+3.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(TcSe2)3 by Materials Project

K2(TcSe2)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of K–Se bond distances ranging from 3.30–3.67 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.32–3.61 Å. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.24–3.89 Å. There are three inequivalent Tc+3.33+ sites. In the first Tc+3.33+ site, Tc+3.33+ is bonded to five Se2- atoms to form edge-sharing TcSe5 square pyramids. There are a spread of Tc–Se bond distances ranging from 2.51–2.63 Å. In the second Tc+3.33+ site, Tc+3.33+ is bonded to five Se2- atoms to form a mixture of corner and edge-sharing TcSe5 square pyramids. There are a spread of Tc–Se bond distances ranging from 2.50–2.68 Å. In the third Tc+3.33+ site, Tc+3.33+ is bonded to five Se2- atoms to form a mixture of corner and edge-sharing TcSe5 square pyramids. There are a spread of Tc–Se bond distances ranging from 2.50–2.68 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to two K1+ and three Tc+3.33+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Tc+3.33+ atoms. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to two K1+ and three Tc+3.33+ atoms. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to three K1+ and three Tc+3.33+ atoms. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to three K1+, one Tc+3.33+, and one Se2- atom. The Se–Se bond length is 2.45 Å. In the sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to three K1+ and two Tc+3.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(ReS2)3 by Materials Project

K2(ReS2)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of K–S bond distances ranging from 3.15–3.53 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of K–S bond distances ranging from 3.16–3.48 Å. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of K–S bond distances ranging from 3.09–3.61 Å. There are three inequivalent Re+3.33+ sites. In the first Re+3.33+ site, Re+3.33+ is bonded to five S2- atoms to form edge-sharing ReS5 square pyramids. There are a spread of Re–S bond distances ranging from 2.41–2.49 Å. In the second Re+3.33+ site, Re+3.33+ is bonded to five S2- atoms to form a mixture of edge and corner-sharing ReS5 square pyramids. There are a spread of Re–S bond distances ranging from 2.40–2.50 Å. In the third Re+3.33+ site, Re+3.33+ is bonded to five S2- atoms to form a mixture of edge and corner-sharing ReS5 square pyramids. There are a spread of Re–S bond distances ranging from 2.40–2.51 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to one K1+ and three Re+3.33+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Re+3.33+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to two K1+ and three Re+3.33+ atoms. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to three K1+ and three Re+3.33+ atoms. In the fifth S2- site, S2- is bonded in a 5-coordinate geometry to three K1+, one Re+3.33+, and one S2- atom. The S–S bond length is 2.14 Å. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to three K1+ and two Re+3.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(MoSe6)3 by Materials Project

K2(MoSe6)3 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 9-coordinate geometry to nine Se+1.11- atoms. There are a spread of K–Se bond distances ranging from 3.45–4.02 Å. In the second K1+ site, K1+ is bonded in a 5-coordinate geometry to six Se+1.11- atoms. There are a spread of K–Se bond distances ranging from 3.37–3.84 Å. There are three inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded to seven Se+1.11- atoms to form distorted face-sharing MoSe7 pentagonal bipyramids. There are a spread of Mo–Se bond distances ranging from 2.50–2.69 Å. In the second Mo6+ site, Mo6+ is bonded to seven Se+1.11- atoms to form distorted face-sharing MoSe7 pentagonal bipyramids. There are a spread of Mo–Se bond distances ranging from 2.54–2.68 Å. In the third Mo6+ site, Mo6+ is bonded to seven Se+1.11- atoms to form face-sharing MoSe7 pentagonal bipyramids. There are a spread of Mo–Se bond distances ranging from 2.54–2.68 Å. There are eighteen inequivalent Se+1.11- sites. In the first Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to one K1+ and three Mo6+ atoms. In the second Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two K1+, one Mo6+, and one Se+1.11- atom. The Se–Se bond length is 2.36 Å. In the third Se+1.11- site, Se+1.11- is bonded in a 1-coordinate geometry to one Mo6+ and two Se+1.11- atoms. The Se–Se bond length is 2.42 Å. In the fourth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+ and one Se+1.11- atom. In the fifth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Mo6+ and one Se+1.11- atom. The Se–Se bond length is 2.35 Å. In the sixth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to one K1+, two Mo6+, and one Se+1.11- atom. In the seventh Se+1.11- site, Se+1.11- is bonded in a 5-coordinate geometry to two Mo6+ atoms. In the eighth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Mo6+ atoms. In the ninth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Mo6+ and one Se+1.11- atom. The Se–Se bond length is 2.42 Å. In the tenth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to one K1+, two Mo6+, and one Se+1.11- atom. In the eleventh Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one Mo6+ and one Se+1.11- atom. The Se–Se bond length is 2.40 Å. In the twelfth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two equivalent K1+ and two Se+1.11- atoms. The Se–Se bond length is 2.42 Å. In the thirteenth Se+1.11- site, Se+1.11- is bonded in a distorted water-like geometry to two Se+1.11- atoms. The Se–Se bond length is 2.43 Å. In the fourteenth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two K1+, one Mo6+, and one Se+1.11- atom. In the fifteenth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two K1+, one Mo6+, and one Se+1.11- atom. The Se–Se bond length is 2.43 Å. In the sixteenth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+ and two Se+1.11- atoms. The Se–Se bond length is 2.37 Å. In the seventeenth Se+1.11- site, Se+1.11- is bonded in a distorted trigonal non-coplanar geometry to one K1+ and two Se+1.11- atoms. The Se–Se bond length is 2.40 Å. In the eighteenth Se+1.11- site, Se+1.11- is bonded in a 1-coordinate geometry to one K1+, one Mo6+, and one Se+1.11- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(TeO4)3 by Materials Project

K2(TeO4)3 crystallizes in the orthorhombic Fdd2 space group. The structure is three-dimensional. K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.72–3.12 Å. There are two inequivalent Te sites. In the first Te site, Te is bonded to six O atoms to form corner-sharing TeO6 octahedra. The corner-sharing octahedra tilt angles range from 48–50°. There are a spread of Te–O bond distances ranging from 1.90–2.01 Å. In the second Te site, Te is bonded to six O atoms to form a mixture of edge and corner-sharing TeO6 octahedra. The corner-sharing octahedra tilt angles range from 48–50°. There are a spread of Te–O bond distances ranging from 1.88–2.03 Å. There are six inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to two equivalent K and one Te atom. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to two equivalent K and one Te atom. In the third O site, O is bonded in a distorted water-like geometry to one K and one Te atom. In the fourth O site, O is bonded in a 3-coordinate geometry to one K and two equivalent Te atoms. In the fifth O site, O is bonded in a distorted trigonal non-coplanar geometry to one K and two Te atoms. In the sixth O site, O is bonded in a 2-coordinate geometry to one K and two Te atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(FeSe)5 by Materials Project

K2(FeSe)5 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. K is bonded in a distorted body-centered cubic geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.32–3.53 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to four Se atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.47–2.49 Å. In the second Fe site, Fe is bonded to four equivalent Se atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. All Fe–Se bond lengths are 2.46 Å. There are two inequivalent Se sites. In the first Se site, Se is bonded in a 7-coordinate geometry to three equivalent K and four Fe atoms. In the second Se site, Se is bonded in a 8-coordinate geometry to four equivalent K and four equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(NbS2)3 by Materials Project

K2(NbS2)3 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. All K–S bond lengths are 3.13 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. All K–S bond lengths are 3.14 Å. There are two inequivalent Nb+3.33+ sites. In the first Nb+3.33+ site, Nb+3.33+ is bonded to six S2- atoms to form distorted edge-sharing NbS6 pentagonal pyramids. There are two shorter (2.50 Å) and four longer (2.51 Å) Nb–S bond lengths. In the second Nb+3.33+ site, Nb+3.33+ is bonded to six S2- atoms to form distorted edge-sharing NbS6 pentagonal pyramids. There are five shorter (2.50 Å) and one longer (2.51 Å) Nb–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent K1+ and three Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SK2Nb3 trigonal bipyramids. In the second S2- site, S2- is bonded to two equivalent K1+ and three Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SK2Nb3 trigonal bipyramids. In the third S2- site, S2- is bonded to two equivalent K1+ and three Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SK2Nb3 square pyramids. In the fourth S2- site, S2- is bonded to two equivalent K1+ and three Nb+3.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SK2Nb3 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(TaS2)3 by Materials Project

K2(TaS2)3 crystallizes in the trigonal R32 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are three shorter (3.11 Å) and three longer (3.14 Å) K–S bond lengths. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are three shorter (3.12 Å) and three longer (3.14 Å) K–S bond lengths. There are three inequivalent Ta+3.33+ sites. In the first Ta+3.33+ site, Ta+3.33+ is bonded to six equivalent S2- atoms to form distorted edge-sharing TaS6 pentagonal pyramids. All Ta–S bond lengths are 2.50 Å. In the second Ta+3.33+ site, Ta+3.33+ is bonded to six equivalent S2- atoms to form distorted edge-sharing TaS6 pentagonal pyramids. There are three shorter (2.48 Å) and three longer (2.50 Å) Ta–S bond lengths. In the third Ta+3.33+ site, Ta+3.33+ is bonded to six equivalent S2- atoms to form distorted edge-sharing TaS6 pentagonal pyramids. There are four shorter (2.49 Å) and two longer (2.50 Å) Ta–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to two K1+ and three Ta+3.33+ atoms. In the second S2- site, S2- is bonded to two K1+ and three equivalent Ta+3.33+ atoms to form a mixture of distorted edge, corner, and face-sharing SK2Ta3 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2(NbSe2)3 by Materials Project

K2(NbSe2)3 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. All K–Se bond lengths are 3.27 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. All K–Se bond lengths are 3.27 Å. There are two inequivalent Nb+3.33+ sites. In the first Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are two shorter (2.63 Å) and four longer (2.64 Å) Nb–Se bond lengths. In the second Nb+3.33+ site, Nb+3.33+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are a spread of Nb–Se bond distances ranging from 2.62–2.64 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Nb+3.33+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent K1+ and three Nb+3.33+ atoms. In the third Se2- site, Se2- is bonded to two equivalent K1+ and three Nb+3.33+ atoms to form a mixture of distorted edge and corner-sharing SeK2Nb3 square pyramids. In the fourth Se2- site, Se2- is bonded to two equivalent K1+ and three Nb+3.33+ atoms to form a mixture of distorted edge and corner-sharing SeK2Nb3 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2015

HATS9-b and HATS10-b: Two compact hot jupiters in field 7 of the K2 mission

We report the discovery of two transiting extrasolar planets by the HATSouth survey. HATS-9b orbits an old (10.8 ± 1.5 Gyr) V = 13.3 G dwarf star with a period P≈1.9153 days. The host star has a mass of 1.03 M{sub ⊙}, radius of 1.503 R{sub ⊙} , and effective temperature 5366 ± 70 K. The planetary companion has a mass of 0.837 M{sub J} and radius of 1.065 R{sub J}, yielding a mean density of 0.85 g cm{sup −3}. HATS-10b orbits a V = 13.1 G dwarf star with a period P≈3.3128 days. The host star has a mass of 1.1 M{sub ⊙}, radius of 1.11 R{sub ⊙} , and effective temperature 5880 ± 120 K. The planetary companion has a mass of 0.53 M{sub J} and radius of 0.97 R{sub J}, yielding a mean density of 0.7 g cm{sup −3}. Both planets are compact in comparison with planets receiving similar irradiation from their host stars and lie in the nominal coordinates of Field 7 of K2, but only HATS-9b falls on working silicon. Future characterization of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature.

79 ASTRONOMY AND ASTROPHYSICS↗