77 research outputs found
TESS delivers its first Earth-sized planet and a warm sub-Neptune
The future of exoplanet science is bright, as TESS once again demonstrates
with the discovery of its longest-period confirmed planet to date. We hereby
present HD 21749b (TOI 186.01), a sub-Neptune in a 36-day orbit around a bright
(V = 8.1) nearby (16 pc) K4.5 dwarf. TESS measures HD21749b to be
2.61 , and combined archival and follow-up
precision radial velocity data put the mass of the planet at
. HD 21749b contributes to the TESS Level 1
Science Requirement of providing 50 transiting planets smaller than 4
with measured masses. Furthermore, we report the discovery of HD
21749c (TOI 186.02), the first Earth-sized () planet from TESS. The HD21749 system is a prime target for
comparative studies of planetary composition and architecture in multi-planet
systems.Comment: Published in ApJ Letters; 5 figures, 1 tabl
TOI-1130: A photodynamical analysis of a hot Jupiter in resonance with an inner low-mass planet
The TOI-1130 is a known planetary system around a K-dwarf consisting of a gas giant planet, TOI-1130 c on an 8.4-day orbit that is accompanied by an inner Neptune-sized planet, TOI-1130 b, with an orbital period of 4.1 days. We collected precise radial velocity (RV) measurements of TOI-1130 with the HARPS and PFS spectrographs as part of our ongoing RV follow-up program. We performed a photodynamical modeling of the HARPS and PFS RVs, along with transit photometry from the Transiting Exoplanet Survey Satellite (TESS) and the TESS Follow-up Observing Program (TFOP). We determined the planet masses and radii of TOI-1130 b and TOI-1130 c to be Mb = 19.28 \ub1 0.97M⊕ and Rb = 3.56 \ub1 0.13 R⊕, and Mc = 325.59 \ub1 5.59M⊕ and Rc = 13.32-1.41+1.55 R⊕, respectively. We have spectroscopically confirmed the existence of TOI-1130 b, which had previously only been validated. We find that the two planets have orbits with small eccentricities in a 2:1 resonant configuration. This is the first known system with a hot Jupiter and an inner lower mass planet locked in a mean-motion resonance. TOI-1130 belongs to the small, yet growing population of hot Jupiters with an inner low-mass planet that poses a challenge to the pathway scenario for hot Jupiter formation. We also detected a linear RV trend that is possibly due to the presence of an outer massive companion
The Magellan-TESS Survey I: Survey Description and Mid-Survey Results
One of the most significant revelations from Kepler is that roughly one-third
of Sun-like stars host planets which orbit their stars within 100 days and are
between the size of Earth and Neptune. How do these super-Earth and sub-Neptune
planets form, what are they made of, and do they represent a continuous
population or naturally divide into separate groups? Measuring their masses and
thus bulk densities can help address these questions of their origin and
composition. To that end, we began the Magellan-TESS Survey (MTS), which uses
Magellan II/PFS to obtain radial velocity (RV) masses of 30 transiting
exoplanets discovered by TESS and develops an analysis framework that connects
observed planet distributions to underlying populations. In the past, RV
measurements of small planets have been challenging to obtain due to the
faintness and low RV semi-amplitudes of most Kepler systems, and challenging to
interpret due to the potential biases in the existing ensemble of small planet
masses from non-algorithmic decisions for target selection and observation
plans. The MTS attempts to minimize these biases by focusing on bright TESS
targets and employing a quantitative selection function and multi-year
observing strategy. In this paper, we (1) describe the motivation and survey
strategy behind the MTS, (2) present our first catalog of planet mass and
density constraints for 25 TESS Objects of Interest (TOIs; 20 in our population
analysis sample, five that are members of the same systems), and (3) employ a
hierarchical Bayesian model to produce preliminary constraints on the
mass-radius (M-R) relation. We find qualitative agreement with prior
mass-radius relations but some quantitative differences (abridged). The the
results of this work can inform more detailed studies of individual systems and
offer a framework that can be applied to future RV surveys with the goal of
population inferences.Comment: 101 pages (39 of main text and references, the rest an appendix of
figures and tables). Submitted to AAS Journal
A planet within the debris disk around the pre-main-sequence star AU Microscopii
AU Microscopii (AU Mic) is the second closest pre main sequence star, at a
distance of 9.79 parsecs and with an age of 22 million years. AU Mic possesses
a relatively rare and spatially resolved3 edge-on debris disk extending from
about 35 to 210 astronomical units from the star, and with clumps exhibiting
non-Keplerian motion. Detection of newly formed planets around such a star is
challenged by the presence of spots, plage, flares and other manifestations of
magnetic activity on the star. Here we report observations of a planet
transiting AU Mic. The transiting planet, AU Mic b, has an orbital period of
8.46 days, an orbital distance of 0.07 astronomical units, a radius of 0.4
Jupiter radii, and a mass of less than 0.18 Jupiter masses at 3 sigma
confidence. Our observations of a planet co-existing with a debris disk offer
the opportunity to test the predictions of current models of planet formation
and evolution.Comment: Nature, published June 24th [author spelling name fix
The TESS Grand Unified Hot Jupiter Survey. II. Twenty New Giant Planets
NASA's Transiting Exoplanet Survey Satellite (TESS) mission promises to
improve our understanding of hot Jupiters by providing an all-sky,
magnitude-limited sample of transiting hot Jupiters suitable for population
studies. Assembling such a sample requires confirming hundreds of planet
candidates with additional follow-up observations. Here, we present twenty hot
Jupiters that were detected using TESS data and confirmed to be planets through
photometric, spectroscopic, and imaging observations coordinated by the TESS
Follow-up Observing Program (TFOP). These twenty planets have orbital periods
shorter than 7 days and orbit relatively bright FGK stars ().
Most of the planets are comparable in mass to Jupiter, although there are four
planets with masses less than that of Saturn. TOI-3976 b, the longest period
planet in our sample ( days), may be on a moderately eccentric orbit
(), while observations of the other targets are consistent
with them being on circular orbits. We measured the projected stellar obliquity
of TOI-1937A b, a hot Jupiter on a 22.4 hour orbit with the Rossiter-McLaughlin
effect, finding the planet's orbit to be well-aligned with the stellar spin
axis (). We also investigated the possibility that
TOI-1937 is a member of the NGC 2516 open cluster, but ultimately found the
evidence for cluster membership to be ambiguous. These objects are part of a
larger effort to build a complete sample of hot Jupiters to be used for future
demographic and detailed characterization work.Comment: 67 pages, 11 tables, 13 figures, 2 figure sets. Resubmitted to ApJS
after revision
Two Massive Jupiters in Eccentric Orbits from the TESS Full-frame Images
We report the discovery of two short-period massive giant planets from NASA's Transiting Exoplanet Survey Satellite (TESS). Both systems, TOI-558 (TIC 207110080) and TOI-559 (TIC 209459275), were identified from the 30 minute cadence full-frame images and confirmed using ground-based photometric and spectroscopic followup observations from TESS's follow-up observing program working group. We find that TOI-558 b, which transits an F-dwarf (M-* =1.349(-0.065)(+0.064) M-circle dot, R-* =1.496(-0.040)(+0.042) R-circle dot, T-eff = 6466(-93)(+95) K, age 1.79(-0.73)(+0.91) Gyr) with an orbital period of 14.574 days, has a mass of 3.61 +/- 0.15 M-J, a radius of 1.086(-0.038)(+0.041) R-J, and an eccentric (e = 0.300(-0.020)(+0.022)) orbit. TOI-559 b transits a G dwarf (M-* = 1.026 +/- 0.057 M-circle dot, R-* =1.233(-0.026)(+0.028) R-circle dot, T-eff = 5925(-76)(+85) K, age 6.8(-2.0)(+2.5) Gyr) in an eccentric (e = 0.151 +/- 0.011) 6.984 days orbit with a mass of 6.01(-0.23)(+0.24) M-J and a radius of 1.091(-0.025+)(0.028) R-J. Our spectroscopic follow up also reveals a long-term radial velocity trend for TOI-559, indicating a long-period companion. The statistically significant orbital eccentricity measured for each system suggests that these planets migrated to their current location through dynamical interactions. Interestingly, both planets are also massive (>3 M-J), adding to the population of massive giant planets identified by TESS. Prompted by these new detections of high-mass planets, we analyzed the known mass distribution of hot and warm Jupiters but find no significant evidence for multiple populations. TESS should provide a near magnitude-limited sample of transiting hot Jupiters, allowing for future detailed population studies
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