144 research outputs found
Orbital alignment of the eccentric warm Jupiter TOI-677 b
Warm Jupiters lay out an excellent laboratory for testing models of planet
formation and migration. Their separation from the host star makes tidal
reprocessing of their orbits ineffective, which preserves the orbital
architectures that result from the planet-forming process. Among the measurable
properties, the orbital inclination with respect to the stellar rotational
axis, stands out as a crucial diagnostic for understanding the migration
mechanisms behind the origin of close-in planets. Observational limitations
have made the procurement of spin-orbit measurements heavily biased toward hot
Jupiter systems. In recent years, however, high-precision spectroscopy has
begun to provide obliquity measurements for planets well into the warm Jupiter
regime. In this study, we present Rossiter-McLaughlin (RM) measurements of the
projected obliquity angle for the warm Jupiter TOI-677 b using ESPRESSO at the
VLT. TOI-677 b exhibits an extreme degree of alignment (
deg), which is particularly puzzling given its significant eccentricity (). TOI-677 b thus joins a growing class of close-in giants that
exhibit large eccentricities and low spin-orbit angles, which is a
configuration not predicted by existing models. We also present the detection
of a candidate outer brown dwarf companion on an eccentric, wide orbit ( and yr). Using simple estimates, we show that this
companion is unlikely to be the cause of the unusual orbit of TOI-677 b.
Therefore, it is essential that future efforts prioritize the acquisition of RM
measurements for warm Jupiters.Comment: 15 pages, 6 figures, 5 tables. Accepted for publication in the
Astronomical Journa
The Aligned Orbit of the Eccentric Proto Hot Jupiter TOI-3362b
High-eccentricity tidal migration predicts the existence of highly eccentric
proto-hot Jupiters on the "tidal circularization track," meaning that they
might eventually become hot Jupiters, but that their migratory journey remains
incomplete. Having experienced moderate amounts of the tidal reprocessing of
their orbital elements, proto-hot Jupiters systems can be powerful test beds
for the underlying mechanisms of eccentricity growth. Notably, they may be used
for discriminating between variants of high-eccentricity migration, each
predicting a distinct evolution of misalignment between the star and the
planet's orbit. We constrain the spin-orbit misalignment of the proto-hot
Jupiter TOI-3362b with high-precision radial velocity observations using
ESPRESSO at VLT. The observations reveal a sky-projected obliquity deg and constrain the orbital eccentricity to , making it one of the most eccentric gas giants for which the obliquity
has been measured. The large eccentricity and the striking orbit alignment of
the planet suggest that ongoing coplanar high-eccentricity migration driven by
a distant companion is a possible explanation for the system's architecture.
This distant companion would need to reside beyond 5 au at 95% confidence to be
compatible with the available radial velocity observations.Comment: ApJL 958 L20 (9 pages, 6 figures
The Aligned Orbit of the Eccentric Proto Hot Jupiter TOI-3362b
High-eccentricity tidal migration predicts the existence of highly eccentric proto hot Jupiters on the “tidal circularization track,” meaning that they might eventually become hot Jupiters, but that their migratory journey remains incomplete. Having experienced moderate amounts of tidal evolution of their orbital elements, proto hot Jupiter systems can be powerful test beds for the underlying mechanisms of eccentricity growth. Notably, they may be used for discriminating between variants of high-eccentricity migration, each predicting a distinct evolution of misalignment between the star and the planet’s orbit. We constrain the spin-orbit misalignment of the proto hot Jupiter TOI-3362b with high-precision radial-velocity observations using ESPRESSO at Very Large Telescope. The observations reveal a sky-projected obliquity λ = 1.2 − 2.7 + 2.8 ° and constrain the orbital eccentricity to e = 0.720 ± 0.016, making it one of the most eccentric gas giants for which the obliquity has been measured. Although the large eccentricity and the striking orbit alignment of the planet are puzzling, we suggest that ongoing coplanar high-eccentricity migration driven by a distant companion is a possible explanation for the system's architecture. This distant companion would need to reside beyond 5 au at 95% confidence to be compatible with the available radial-velocity observations. © 2023. The Author(s). Published by the American Astronomical Society.We would like to thank Jiayin Dong for useful discussions on the implementation of the RM effect in exoplanet. J.I.E.R. acknowledges support from the National Agency for Research and Development (ANID) Doctorado Nacional grant 2021-21212378. A.J., R.B., C.P., and M.H. acknowledge support from ANID-Millennium Science Initiative-ICN12_009. C.P. acknowledges support from CATA-Basal AFB-170002, ANID BASAL project FB210003, FONDECYT Regular grant 1210425, CASSACA grant CCJRF2105, and ANID+REC Convocatoria Nacional subvencion a la instalacion en la Academia convocatoria 2020 PAI77200076. R.B. acknowledges support from FONDECYT project 11200751. A.J. acknowledges support from FONDECYT project 1210718. G.S. acknowledges support provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51519.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555
ESPRESSO Observations of Gaia BH1:High-precision Orbital Constraints and no Evidence for an Inner Binary
We present high-precision radial velocity observations of Gaia BH1, the nearest known black hole (BH). The system contains a solar-type G star orbiting a massive dark companion, which could be either a single BH or an inner BH + BH binary. A BH + BH binary is expected in some models where Gaia BH1 formed as a hierarchical triple, which is attractive because they avoid many of the difficulties associated with forming the system through isolated binary evolution. Our observations test the inner binary scenario. We have measured 115 precise RVs of the G star, including 40 from ESPRESSO with a precision of 3–5 m s−1, and 75 from other instruments with a typical precision of 30–100 m s−1. Our observations span 2.33 orbits of the G star and are concentrated near a periastron passage, when perturbations due to an inner binary would be largest. The RVs are well-fit by a Keplerian two-body orbit and show no convincing evidence of an inner binary. Using REBOUND simulations of hierarchical triples with a range of inner periods, mass ratios, eccentricities, and orientations, we show that plausible inner binaries with periods Pinner ≳ 1.5 days would have produced larger deviations from a Keplerian orbit than observed. Binaries with Pinner ≲ 1.5 days are consistent with the data, but these would merge within a Hubble time and would thus imply fine-tuning. We present updated parameters of Gaia BH1's orbit. The RVs yield a spectroscopic mass function f(MBH)=3.9358±0.0002M⊙—about 7000σ above the ∼2.5 M⊙ maximum neutron star mass. Including the inclination constraint from Gaia astrometry, this implies a BH mass of MBH = 9.27 ± 0.10 M⊙
TOI-3235 b: a transiting giant planet around an M4 dwarf star
We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an
M-dwarf with a stellar mass close to the critical mass at which stars
transition from partially to fully convective. TOI-3235 b was first identified
as a candidate from TESS photometry, and confirmed with radial velocities from
ESPRESSO, and ground-based photometry from HATSouth, MEarth-South,
TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of
and a radius of . It
orbits close to its host star, with an orbital period of ,
but has an equilibrium temperature of , well below
the expected threshold for radius inflation of hot Jupiters. The host star has
a mass of , a radius of
, an effective temperature of , and a J-band magnitude of . Current planet
formation models do not predict the existence of gas giants such as TOI-3235 b
around such low-mass stars. With a high transmission spectroscopy metric,
TOI-3235 b is one of the best-suited giants orbiting M-dwarfs for atmospheric
characterization.Comment: 15 pages, 4 figures. Accepted for publication in APJ
Three Warm Jupiters around Solar-analog Stars Detected with TESS*
We report the discovery and characterization of three giant exoplanets orbiting solar-analog stars, detected by the TESS space mission and confirmed through ground-based photometry and radial velocity measurements taken at La Silla observatory with FEROS. TOI-2373 b is a warm Jupiter orbiting its host star every ∼13.3 days, and is one of the most massive known exoplanet with a precisely determined mass and radius around a star similar to the Sun, with an estimated mass of m _p = and a radius of r _p = . With a mean density of , TOI-2373 b is among the densest planets discovered so far. TOI-2416 b orbits its host star on a moderately eccentric orbit with a period of ∼8.3 days and an eccentricity of e = . TOI-2416 b is more massive than Jupiter with m _p = , however is significantly smaller with a radius of r _p = , leading to a high mean density of . TOI-2524 b is a warm Jupiter near the hot Jupiter transition region, orbiting its star every ∼7.2 days on a circular orbit. It is less massive than Jupiter with a mass of m _p = , and is consistent with an inflated radius of r _p = , leading to a low mean density of . The newly discovered exoplanets TOI-2373 b, TOI-2416 b, and TOI-2524 b have estimated equilibrium temperatures of K, K, and K, respectively, placing them in the sparsely populated transition zone between hot and warm Jupiters
Biomarker-Directed Targeted Therapy Plus Durvalumab in Advanced Non-Small-Cell Lung Cancer: A Phase 2 Umbrella Trial
For patients with non-small-cell lung cancer (NSCLC) tumors without currently targetable molecular alterations, standard-of-care treatment is immunotherapy with anti-PD-(L)1 checkpoint inhibitors, alone or with platinum-doublet therapy. However, not all patients derive durable benefit and resistance to immune checkpoint blockade is common. Understanding mechanisms of resistance—which can include defects in DNA damage response and repair pathways, alterations or functional mutations in STK11/LKB1, alterations in antigen-presentation pathways, and immunosuppressive cellular subsets within the tumor microenvironment—and developing effective therapies to overcome them, remains an unmet need. Here the phase 2 umbrella HUDSON study evaluated rational combination regimens for advanced NSCLC following failure of anti-PD-(L)1-containing immunotherapy and platinum-doublet therapy. A total of 268 patients received durvalumab (anti-PD-L1 monoclonal antibody)–ceralasertib (ATR kinase inhibitor), durvalumab–olaparib (PARP inhibitor), durvalumab–danvatirsen (STAT3 antisense oligonucleotide) or durvalumab–oleclumab (anti-CD73 monoclonal antibody). Greatest clinical benefit was observed with durvalumab–ceralasertib; objective response rate (primary outcome) was 13.9% (11/79) versus 2.6% (5/189) with other regimens, pooled, median progression-free survival (secondary outcome) was 5.8 (80% confidence interval 4.6–7.4) versus 2.7 (1.8–2.8) months, and median overall survival (secondary outcome) was 17.4 (14.1–20.3) versus 9.4 (7.5–10.6) months. Benefit with durvalumab–ceralasertib was consistent across known immunotherapy-refractory subgroups. In ATM-altered patients hypothesized to harbor vulnerability to ATR inhibition, objective response rate was 26.1% (6/23) and median progression-free survival/median overall survival were 8.4/22.8 months. Durvalumab–ceralasertib safety/tolerability profile was manageable. Biomarker analyses suggested that anti-PD-L1/ATR inhibition induced immune changes that reinvigorated antitumor immunity. Durvalumab–ceralasertib is under further investigation in immunotherapy-refractory NSCLC
The SOPHIE search for northern extrasolar planets XIV. A temperate (Teq ~ 300 K) super-earth around the nearby star Gliese 411
Periodic radial velocity variations in the nearby M-dwarf star Gl 411 are reported, based on measurements with the SOPHIE spectrograph. Current data do not allow us to distinguish between a 12.95-day period and its one-day alias at 1.08 days, but favour the former slightly. The velocity variation has an amplitude of 1.6 m s−1, making this the lowest-amplitude signal detected with SOPHIE up to now. We have performed a detailed analysis of the significance of the signal and its origin, including extensive simulations with both uncorrelated and correlated noise, representing the signal induced by stellar activity. The signal is significantly detected, and the results from all tests point to its planetary origin. Additionally, the presence of an additional acceleration in the velocity time series is suggested by the current data. On the other hand, a previously reported signal with a period of 9.9 days, detected in HIRES velocities of this star, is not recovered in the SOPHIE data. An independent analysis of the HIRES dataset also fails to unveil the 9.9-day signal. If the 12.95-day period is the real one, the amplitude of the signal detected with SOPHIE implies the presence of a planet, called Gl 411 b, with a minimum mass of around three Earth masses, orbiting its star at a distance of 0.079 AU. The planet receives about 3.5 times the insolation received by Earth, which implies an equilibrium temperature between 256 and 350 K, and makes it too hot to be in the habitable zone. At a distance of only 2.5 pc, Gl 411 b, is the third closest low-mass planet detected to date. Its proximity to Earth will permit probing its atmosphere with a combination of high-contrast imaging and high-dispersion spectroscopy in the next decade
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