15 research outputs found
TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley
Studies of close-in planets orbiting M dwarfs have suggested that the M dwarf
radius valley may be well-explained by distinct formation timescales between
enveloped terrestrials, and rocky planets that form at late times in a
gas-depleted environment. This scenario is at odds with the picture that
close-in rocky planets form with a primordial gaseous envelope that is
subsequently stripped away by some thermally-driven mass loss process. These
two physical scenarios make unique predictions of the rocky/enveloped
transition's dependence on orbital separation such that studying the
compositions of planets within the M dwarf radius valley may be able to
establish the dominant physics. Here, we present the discovery of one such
keystone planet: the ultra-short period planet TOI-1634 b ( days,
, ) orbiting a
nearby M2 dwarf (, , ) and
whose size and orbital period sit within the M dwarf radius valley. We confirm
the TESS-discovered planet candidate using extensive ground-based follow-up
campaigns, including a set of 32 precise radial velocity measurements from
HARPS-N. We measure a planetary mass of ,
which makes TOI-1634 b inconsistent with an Earth-like composition at
and thus requires either an extended gaseous envelope, a large
volatile-rich layer, or a rocky portion that is not dominated by iron and
silicates to explain its mass and radius. The discovery that the bulk
composition of TOI-1634 b is inconsistent with that of the Earth favors the
gas-depleted formation mechanism to explain the emergence of the radius valley
around M dwarfs with
A super-Earth and a sub-Neptune orbiting the bright, quiet M3 dwarf TOI-1266
We report the discovery and characterisation of a super-Earth and a
sub-Neptune transiting the bright (), quiet, and nearby (37 pc) M3V
dwarf TOI-1266. We validate the planetary nature of TOI-1266 b and c using four
sectors of TESS photometry and data from the newly-commissioned 1-m SAINT-EX
telescope located in San Pedro M\'artir (Mexico). We also include additional
ground-based follow-up photometry as well as high-resolution spectroscopy and
high-angular imaging observations. The inner, larger planet has a radius of
R and an orbital period of 10.9 days. The
outer, smaller planet has a radius of R on
an 18.8-day orbit. The data are found to be consistent with circular, co-planar
and stable orbits that are weakly influenced by the 2:1 mean motion resonance.
Our TTV analysis of the combined dataset enables model-independent constraints
on the masses and eccentricities of the planets. We find planetary masses of
= (
at 2-) for TOI-1266 b and
( at 2-) for TOI-1266
c. We find small but non-zero orbital eccentricities of
( at 2-) for TOI-1266 b and ( at
2-) for TOI-1266 c. The equilibrium temperatures of both planets are of
K and K, respectively, assuming a null Bond albedo and
uniform heat redistribution from the day-side to the night-side hemisphere. The
host brightness and negligible activity combined with the planetary system
architecture and favourable planet-to-star radii ratios makes TOI-1266 an
exquisite system for a detailed characterisation
Web-based infectious disease surveillance systems and public health perspectives: a systematic review
This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.Abstract
Background
Emerging and re-emerging infectious diseases are a significant public health concern, and early detection and immediate response is crucial for disease control. These challenges have led to the need for new approaches and technologies to reinforce the capacity of traditional surveillance systems for detecting emerging infectious diseases. In the last few years, the availability of novel web-based data sources has contributed substantially to infectious disease surveillance. This study explores the burgeoning field of web-based infectious disease surveillance systems by examining their current status, importance, and potential challenges.
Methods
A systematic review framework was applied to the search, screening, and analysis of web-based infectious disease surveillance systems. We searched PubMed, Web of Science, and Embase databases to extensively review the English literature published between 2000 and 2015. Eleven surveillance systems were chosen for evaluation according to their high frequency of application. Relevant terms, including newly coined terms, development and classification of the surveillance systems, and various characteristics associated with the systems were studied.
Results
Based on a detailed and informative review of the 11 web-based infectious disease surveillance systems, it was evident that these systems exhibited clear strengths, as compared to traditional surveillance systems, but with some limitations yet to be overcome. The major strengths of the newly emerging surveillance systems are that they are intuitive, adaptable, low-cost, and operated in real-time, all of which are necessary features of an effective public health tool. The most apparent potential challenges of the web-based systems are those of inaccurate interpretation and prediction of health status, and privacy issues, based on an individuals internet activity.
Conclusion
Despite being in a nascent stage with further modification needed, web-based surveillance systems have evolved to complement traditional national surveillance systems. This review highlights ways in which the strengths of existing systems can be maintained and weaknesses alleviated to implement optimal web surveillance systems
TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images
We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP = 1.01–1.77 RJ) and have masses that range from 0.85 to 6.33 MJ. The host stars of these systems have F and G spectral types (5595 ≤ Teff ≤ 6460 K) and are all relatively bright (9.5 1.7 RJ, possibly a result of its host star's evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of MJ and a statistically significant, nonzero orbital eccentricity of e = . This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P = 10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA's TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals
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TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley
Studies of close-in planets orbiting M dwarfs have suggested that the M dwarf
radius valley may be well-explained by distinct formation timescales between
enveloped terrestrials, and rocky planets that form at late times in a
gas-depleted environment. This scenario is at odds with the picture that
close-in rocky planets form with a primordial gaseous envelope that is
subsequently stripped away by some thermally-driven mass loss process. These
two physical scenarios make unique predictions of the rocky/enveloped
transition's dependence on orbital separation such that studying the
compositions of planets within the M dwarf radius valley may be able to
establish the dominant physics. Here, we present the discovery of one such
keystone planet: the ultra-short period planet TOI-1634 b ( days,
, ) orbiting a
nearby M2 dwarf (, , ) and
whose size and orbital period sit within the M dwarf radius valley. We confirm
the TESS-discovered planet candidate using extensive ground-based follow-up
campaigns, including a set of 32 precise radial velocity measurements from
HARPS-N. We measure a planetary mass of ,
which makes TOI-1634 b inconsistent with an Earth-like composition at
and thus requires either an extended gaseous envelope, a large
volatile-rich layer, or a rocky portion that is not dominated by iron and
silicates to explain its mass and radius. The discovery that the bulk
composition of TOI-1634 b is inconsistent with that of the Earth favors the
gas-depleted formation mechanism to explain the emergence of the radius valley
around M dwarfs with
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Inhomogeneous terminators on the exoplanet WASP-39 b
This is the author accepted manuscript. The final version is available from Nature Research via the DOI in this recordData Availability: The raw data from this study is available as part of the Early Release Science Observations (ERS) via the Space Science Telescope Institute’s Mikulski Archive for Space Telescopes (https://archive.stsci.edu/). All the figures in this manuscript, along with the associated data and code to reproduce them, can be found at https://github.com/nespinoza/wasp39-terminators. Reduced data along with prior and posterior distributions for our wavelength-dependant catwoman (NE) light curve fits used to obtain the main results of this work can be found at https://stsci.box.com/s/rx7u56zviu3up2p8p34qh3btwop6lgl6. Reduced data along with prior and posterior distributions for our white-light light curve fit performed for WASP-39 b and described in the Methods section can be found at https://stsci.box.com/s/wet5xmacrk26ughr8y2j8wpyjdsumco1. Both datasets contain human-readable outputs, and are packaged to be explored using the juliet software library, which is publicly available at https://github.com/nespinoza/juliet.Code Availability:
Light curves were fitted using juliet
(https://github.com/nespinoza/juliet), batman
(https://github.com/lkreidberg/batman), catwoman
(https://github.com/KathrynJones1/catwoman) and
Tiberius (https://github.com/JamesKirk11/
Tiberius), all of which are publicly available.Heising-Simons Foundatio