12 research outputs found
Planet Hunters X: Searching for Nearby Neighbors of 75 Planet and Eclipsing Binary Candidates from the K2 Kepler Extended Mission
We present high-resolution observations of a sample of 75 K2 targets from
Campaigns 1-3 using speckle interferometry on the Southern Astrophysical
Research (SOAR) telescope and adaptive optics (AO) imaging at the Keck II
telescope. The median SOAR -band and Keck -band detection limits at 1"
were ~mag and ~mag, respectively. This
sample includes 37 stars likely to host planets, 32 targets likely to be
eclipsing binaries (EBs), and 6 other targets previously labeled as likely
planetary false positives. We find nine likely physically bound companion stars
within 3" of three candidate transiting exoplanet host stars and six likely
EBs. Six of the nine detected companions are new discoveries; one of the six,
EPIC 206061524, is associated with a planet candidate. Among the EB candidates,
companions were only found near the shortest period ones ( days), which is
in line with previous results showing high multiplicity near short-period
binary stars. This high-resolution data, including both the detected companions
and the limits on potential unseen companions, will be useful in future planet
vetting and stellar multiplicity rate studies for planets and binaries.Comment: Accepted in A
Planet Hunters. VI: An Independent Characterization of KOI-351 and Several Long Period Planet Candidates from the Kepler Archival Data
We report the discovery of 14 new transiting planet candidates in the Kepler
field from the Planet Hunters citizen science program. None of these candidates
overlapped with Kepler Objects of Interest (KOIs) at the time of submission. We
report the discovery of one more addition to the six planet candidate system
around KOI-351, making it the only seven planet candidate system from Kepler.
Additionally, KOI-351 bears some resemblance to our own solar system, with the
inner five planets ranging from Earth to mini-Neptune radii and the outer
planets being gas giants; however, this system is very compact, with all seven
planet candidates orbiting AU from their host star. A Hill
stability test and an orbital integration of the system shows that the system
is stable. Furthermore, we significantly add to the population of long period
transiting planets; periods range from 124-904 days, eight of them more than
one Earth year long. Seven of these 14 candidates reside in their host star's
habitable zone.Comment: 27 pages, 6 figures, 5 tables, Accepted to AJ (in press) (updated
title from original astro-ph submission
Planet Hunters. VIII. Characterization of 41 Long-Period Exoplanet Candidates from Kepler Archival Data
The census of exoplanets is incomplete for orbital distances larger than 1
AU. Here, we present 41 long-period planet candidates in 38 systems identified
by Planet Hunters based on Kepler archival data (Q0-Q17). Among them, 17
exhibit only one transit, 14 have two visible transits and 10 have more than
three visible transits. For planet candidates with only one visible transit, we
estimate their orbital periods based on transit duration and host star
properties. The majority of the planet candidates in this work (75%) have
orbital periods that correspond to distances of 1-3 AU from their host stars.
We conduct follow-up imaging and spectroscopic observations to validate and
characterize planet host stars. In total, we obtain adaptive optics images for
33 stars to search for possible blending sources. Six stars have stellar
companions within 4". We obtain high-resolution spectra for 6 stars to
determine their physical properties. Stellar properties for other stars are
obtained from the NASA Exoplanet Archive and the Kepler Stellar Catalog by
Huber et al. (2014). We validate 7 planet candidates that have planet
confidence over 0.997 (3-{\sigma} level). These validated planets include 3
single-transit planets (KIC-3558849b, KIC-5951458b, and KIC-8540376c), 3
planets with double transits (KIC-8540376b, KIC-9663113b, and KIC-10525077b),
and 1 planet with 4 transits (KIC-5437945b). This work provides assessment
regarding the existence of planets at wide separations and the associated false
positive rate for transiting observation (17%-33%). More than half of the
long-period planets with at least three transits in this paper exhibit transit
timing variations up to 41 hours, which suggest additional components that
dynamically interact with the transiting planet candidates. The nature of these
components can be determined by follow-up radial velocity and transit
observations.Comment: Published on ApJ, 815, 127 Notations of validated planets are changed
in accordance with naming convention of NASA Exoplanet Archiv
Mechanical and metallurgical characteristics of the stress-test of a pipeline produced by welding thermomechanically treated steel
Translated from Czech (Kovove Mater. 1997 (5) p. 313-321)Available from British Library Document Supply Centre-DSC:9023.190(VR-Trans--8694)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Planet Hunters X: Searching for nearby neighbors of 75 planet and eclipsing binary candidates from the K2 Kepler extended mission
We present high resolution observations of a sample of 75 K2 targets from
Campaigns 1-3 using speckle interferometry on the Southern Astrophysical
Research (SOAR) telescope and adaptive optics (AO) imaging at the Keck II
telescope. The median SOAR -band and Keck -band detection limits at 1''
were mag and mag, respectively. This
sample includes 37 stars likely to host planets, 32 targets likely to be EBs,
and 6 other targets previously labeled as likely planetary false positives. We
find nine likely physically bound companion stars within 3'' of three candidate
transiting exoplanet host stars and six likely eclipsing binaries (EB). Six of
the nine detected companions are new discoveries, one of them associated with a
planet candidate (EPIC 206061524). Among the EB candidates, companions were
only found near the shortest period ones ( days), which is in line with
previous results showing high multiplicity near short-period binary stars. This
high resolution data, including both the detected companions and the limits on
potential unseen companions, will be useful in future planet vetting and
stellar multiplicity rate studies for planets and binaries
Planet Hunters. VI: An Independent Characterization of KOI-351 and Several Long Period Planet Candidates from the Kepler Archival Data
We report the discovery of 14 new transiting planet candidates in the Kepler field from the Planet Hunters citizen science program. None of these candidates overlapped with Kepler Objects of Interest (KOIs) at the time of submission. We report the discovery of one more addition to the six planet candidate system around KOI-351, making it the only seven planet candidate system from Kepler. Additionally, KOI-351 bears some resemblance to our own solar system, with the inner five planets ranging from Earth to mini-Neptune radii and the outer planets being gas giants; however, this system is very compact, with all seven planet candidates orbiting AU from their host star. A Hill stability test and an orbital integration of the system shows that the system is stable. Furthermore, we significantly add to the population of long period transiting planets; periods range from 124-904 days, eight of them more than one Earth year long. Seven of these 14 candidates reside in their host star's habitable zone
Planet Hunters X: Searching for nearby neighbors of 75 planet and eclipsing binary candidates from the K2 Kepler extended mission
We present high resolution observations of a sample of 75 K2 targets from Campaigns 1-3 using speckle interferometry on the Southern Astrophysical Research (SOAR) telescope and adaptive optics (AO) imaging at the Keck II telescope. The median SOAR -band and Keck -band detection limits at 1'' were mag and mag, respectively. This sample includes 37 stars likely to host planets, 32 targets likely to be EBs, and 6 other targets previously labeled as likely planetary false positives. We find nine likely physically bound companion stars within 3'' of three candidate transiting exoplanet host stars and six likely eclipsing binaries (EB). Six of the nine detected companions are new discoveries, one of them associated with a planet candidate (EPIC 206061524). Among the EB candidates, companions were only found near the shortest period ones (P<3 days), which is in line with previous results showing high multiplicity near short-period binary stars. This high resolution data, including both the detected companions and the limits on potential unseen companions, will be useful in future planet vetting and stellar multiplicity rate studies for planets and binaries
Planet Hunters TESS IV: a massive, compact hierarchical triple star system TIC 470710327
We report the discovery and analysis of a massive, compact, hierarchical triple system (TIC 470710327) initially identified by citizen scientists in data obtained by NASA's Transiting Exoplanet Survey Satellite (TESS). Spectroscopic follow-up observations obtained with the HERMES spectrograph, combined with eclipse-timing variations (ETVs), confirm that the system is comprised of three OB stars, with a compact 1.10 d eclipsing binary and a non-eclipsing tertiary on a 52.04 d orbit. Dynamical modelling of the system (from radial velocity and ETVs) reveal a rare configuration wherein the tertiary star (O9.5-B0.5V; 14-17 M⊙) is more massive than the combined mass of the inner binary (10.9-13.2 M⊙). Given the high mass of the tertiary, we predict that this system will undergo multiple phases of mass transfer in the future, and likely end up as a double neutron star gravitational wave progenitor or an exotic Thorne-Żytkow object. Further observational characterization of this system promises constraints on both formation scenarios of massive stars as well as their exotic evolutionary end-products