We present the results of an all-sky survey made with the Fine Guidance Sensor on the Hubble Space Telescope to search for angularly resolved binary systems among massive stars. The sample of 224 ...stars is comprised mainly of Galactic O- and B-type stars and luminous blue variables, plus a few luminous stars in the Large Magellanic Cloud. The FGS TRANS mode observations are sensitive to the detection of companions with an angular separation between 0".01 and 1".0 and brighter than delta m = 5. The FGS observations resolved 52 binary and 6 triple star systems and detected partially resolved binaries in 7 additional targets (43 of these are new detections). These numbers yield a companion detection frequency of 29% for the FGS survey. We also gathered literature results on the numbers of close spectroscopic binaries and wider astrometric binaries among the sample, and we present estimates of the frequency of multiple systems and the companion frequency for subsets of stars residing in clusters and associations, field stars, and runaway stars. These results confirm the high multiplicity fraction, especially among massive stars in clusters and associations. We show that the period distribution is approximately flat in increments of log P. We identify a number of systems of potential interest for long-term orbital determinations, and we note the importance of some of these companions for the interpretation of the radial velocities and light curves of close binaries that have third companions.
DS Tuc Ab is a Neptune-sized planet that orbits around a G star in the 45 Myr old Tucana-Horologium moving group. Here, we report the measurement of the sky-projected angle between the stellar spin ...axis and the planet's orbital axis, based on the observation of the Rossiter-McLaughlin effect during three separate planetary transits. The orbit appears to be well aligned with the equator of the host star, with a projected obliquity of . In addition to the distortions in the stellar absorption lines due to the transiting planet, we observed variations that we attribute to large starspots, with angular sizes of tens of degrees. The technique that we have developed for simultaneous modeling of starspots and the planet-induced distortions may be useful in other observations of planets around active stars.
Context.
The Multi-site All-Sky CAmeRA (MASCARA) and bRing are both photometric ground-based instruments with multiple stations that rely on interline charge-coupled devices with wide-field lenses to ...monitor bright stars in the local sky for variability. MASCARA has already discovered several planets in the northern sky, which are among the brightest known transiting hot Jupiter systems.
Aims.
In this paper, we aim to characterize a transiting planetary candidate in the southern skies found in the combined MASCARA and bRing data sets of HD 85628, an A7V star of
V
= 8.2 mag at a distance 172 pc, to establish its planetary nature.
Methods.
The candidate was originally detected in data obtained jointly with the MASCARA and bRing instruments using a Box Least-Square search for transit events. Further photometry was taken by the 0.7 m Chilean-Hungarian Automated Telescope (CHAT), and radial velocity measurements with the Fiber Dual Echelle Optical Spectrograph on the European Southern Observatory 1.0 m Telescope. High-resolution spectra during a transit were taken with the CTIO high-resolution spectrometer (CHIRON) on the Small and Moderate Aperture Research Telescope System 1.5 m telescope to target the Doppler shadow of the candidate.
Results.
We confirm the existence of a hot Jupiter transiting the bright A7V star HD 85628, which we co-designate as MASCARA-4b and bRing-1b. It is in an orbit of 2.824 days, with an estimated planet radius of 1.53
−0.04
+0.07
R
Jup
and an estimated planet mass of 3.1 ± 0.9
M
Jup
, putting it well within the planetary regime. The CHAT observations show a partial transit, reducing the probability that the transit was around a faint background star. The CHIRON observations show a clear Doppler shadow, implying that the transiting object is in a retrograde orbit with |
λ
| =244.9
−3.6
+2.7
°. The planet orbits at a distance of 0.047 ± 0.004 AU from the star and has a zero-albedo equilibrium temperature of 2100 ± 100 K. In addition, we find that HD 85628 has a previously unreported stellar companion star in the
Gaia
DR2 data demonstrating common proper motion and parallax at 4.3′′ separation (projected separation ~740 AU), and with absolute magnitude consistent with being a K/M dwarf.
Conclusions.
MASCARA-4 b/bRing-1 b is the brightest transiting hot Jupiter known to date in a retrograde orbit. It further confirms that planets in near-polar and retrograde orbits are more common around early-type stars. Due to its high apparent brightness and short orbital period, the system is particularly well suited for further atmospheric characterization.
ABSTRACT We present a carefully vetted equatorial ( 30 decl.) sample of all known single (within 4″) mid M dwarfs (M2.5 V-M8.0 V) extending out to 10 pc; their proximity and low masses make them ...ideal targets for planet searches. For this sample of 58 stars, we provide VJ, RKC, and IKC photometry, new low-dispersion optical (6000-9000 ) spectra from which uniform spectral types are determined, multi-epoch H equivalent widths, and gravity-sensitive Na i indices. For 12 of these 58 stars, strict limits are placed on the presence of stellar and substellar companions based on a pioneering program described here that utilizes precise infrared radial velocities (RVs) and optical astrometric measurements in an effort to search for Jupiter-mass, brown dwarf, and stellar-mass companions. Our infrared RV precision using CSHELL at NASA's Infrared Telescope Facility is ∼90 m s−1 over timescales from 13 days to 5 yr. With our spectroscopic results the mean companion masses that we rule out of existence are 1.5 MJUP or greater in 10 day orbital periods and 7 MJUP or greater in 100 day orbital periods. We use these spectra to determine rotational velocities and absolute RVs of these 12 stars. Our mean astrometric precision using Research Consortium on Nearby Stars (RECONS; www.recons.org) data from the 0.9 m telescope at Cerro Tololo Inter-American Observatory is ∼3 mas over baselines ranging from 9 to 13 yr. With our astrometric results the mean companion masses that we rule out of existence are greater than 11.5 MJUP with an orbital period of 4 yr and greater than 7.5 MJUP with an orbital period of 8 yr. Although we do not detect companions around our subsample of 12 stars, we demonstrate that our two techniques probe a regime that is commonly missed in other companion searches of late-type stars.
We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the fine guidance sensor 1R (FGS1r) on the Hubble Space Telescope. ...FGS1r is able to resolve binary systems with a magnitude difference Delta V < 4 down to separations as small as 0".01. The sample includes 58 of the brighter members of Cyg OB2, one of the closest examples of an environment containing a large number of very young and massive stars. We resolved binary companions for 12 targets and confirmed the triple nature of one other target, and we offer evidence of marginally resolved companions for two additional stars. We confirm the binary nature of 11 of these systems from complementary adaptive optics imaging observations. The overall binary frequency in our study is 22% to 26% corresponding to orbital periods ranging from 20 to 20,000 yr. When combined with the known short-period spectroscopic binaries, the results support the hypothesis that the binary fraction among massive stars is >60%. One of the new discoveries is a companion to the hypergiant star MT 304 = Cyg OB2-12, and future measurements of orbital motion should provide mass estimates for this very luminous star.
Trigonometric parallaxes, proper motions and VJ(RI)KC photometry are given for 25 stars (of which one is a zero-parallax control field) targeted by the Cerro Tololo Inter-American Observatory ...Parallax Investigation (CTIOPI), a widely scoped program aimed at discovering and characterizing nearby stars. The trigonometric parallaxes and proper motions presented are the last that were obtained with the CTIO 1.5 m telescope, which targeted the fainter subset of the CTIOPI input list. First trigonometric parallaxes are given for 22 systems, of which one is within 10 pc (DENIS 0255-4700), and 10 of which are between 10 and 25 pc. At a distance of 4.97 ± 0.10 pc, and with a spectral type of L7.5 V, DENIS 0255-4700 is now the closest known L dwarf. In addition, with MV = 24.44, it is the faintest dwarf with a measured absolute visual magnitude. We present preliminary trigonometric parallaxes for five additional systems worthy of follow-up, and VRIJHKS photometry and photometric distance estimates for four of them. We also give photometry and distance estimates for 21 other promising targets in our input list for which definitive trigonometric parallaxes were not possible; 13 are likely to be closer than 25 pc. We also present color-magnitude and color-color diagrams, which, in combination with theoretical isochrones from the literature, tangential velocities, and MR and MJ, have aided to identify the general nature of each of our targets. We have in this way discovered one new (spectroscopically confirmed) subdwarf and two suspected extreme subdwarfs that could be among the most extreme cases of these objects. We have also identified several very low mass stars, a few of which could be brown dwarfs. This concludes the CTIOPI 1.5 m program, from which we have derived a total of 69 trigonometric parallaxes (55 definitive, 6 preliminary, and 8 calibration).
ObjectiveNon-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome and is associated with cardiovascular risk. The aim of this study was to determine the role of ...fatty liver in predicting coronary artery disease and clinical outcomes in patients undergoing coronary angiogram.MethodsThis was a prospective cohort study carried out in a University hospital. Consecutive patients who underwent coronary angiogram had ultrasound screening for fatty liver. Significant cardiovascular disease was defined as ≥50% stenosis in at least one coronary artery. The primary outcome was a composite end point comprising cardiovascular deaths, non-fatal myocardial infarction and the need for further coronary intervention during prospective follow-up.ResultsAmong 612 recruited patients, 356 (58.2%) had fatty liver by ultrasonography, 318 (52.0%) had elevated serum alanine aminotransferase and 465 (76.0%) had significant coronary artery disease. Coronary artery disease occurred in 84.6% of patients with fatty liver and 64.1% of those without fatty liver (p<0.001). After adjusting for demographic and metabolic factors, fatty liver (adjusted OR 2.31; 95% CI 1.46 to 3.64) and alanine aminotransferase level (adjusted OR 1.01; 95% CI 1.00 to 1.02) remained independently associated with coronary artery disease. At a mean follow-up of 87±22 weeks, 30 (10.0%) patients with fatty liver and 18 (11.0%) patients without fatty liver reached the composite clinical end point (p=0.79).ConclusionsIn patients with clinical indications for coronary angiogram, fatty liver is associated with coronary artery disease independently of other metabolic factors. However, fatty liver cannot predict cardiovascular mortality and morbidity in patients with established coronary artery disease.
We compared the perioperative parameters and outcomes achieved with hand-assisted laparoscopic colectomy (HALC) vs open colectomy (OC) for the management of benign and malignant colorectal disease, ...including cancer patients treated with curative intent.
Sixty eligible patients were randomized to either HALC (n = 30) or OC (n = 30) treatment groups. We used Pearson's chi-square and two-sample t-tests to compare the differences in demographics and perioperative parameters.
There were no significant differences in age, gender distribution, disease pattern, operative procedure, comorbidity, or history of abdominal surgery. The HALC patients had significantly shorter hospital stays and incision lengths, faster recovery of gastrointestinal function, less analgesic use and blood loss, and lower pain scores on postoperative days 1, 3, and 14. There were no significant differences in operative time, complications, or time to return to normal activity.
Hand-assisted laparoscopic colectomy (HALC) is safe and produces better therapeutic results in terms of perioperative parameters than OC.
ObjectiveNon-alcoholic fatty liver disease (NAFLD) affects 20–40% of the general adult population. Due to shared risk factors, it is postulated that NAFLD patients have an increased risk of ...colorectal neoplasm and should be a target group for screening. The aim of this study was to examine the prevalence of colorectal neoplasm in NAFLD patients and the risk of colorectal neoplasm in relation to the severity of NAFLD histology.DesignCross-sectional study.SettingUniversity hospital with case recruitment from the community and clinics.PatientsSubjects aged 40–70 years were recruited for colonoscopic screening from two study cohorts: (1) community subjects; and (2) consecutive patients with biopsy proven NAFLD. In the community cohort, hepatic fat was measured by proton-magnetic resonance spectroscopy.Main outcome measuresPrevalence of colorectal adenomas. Advanced colorectal neoplasm was defined as cancer or adenomas with villous architecture or high grade dysplasia.ResultsNAFLD patients (N=199) had a higher prevalence of colorectal adenomas (34.7% vs 21.5%; p=0.043) and advanced neoplasms (18.6% vs 5.5%; p=0.002) than healthy controls (N=181). Thirteen of 29 (45%) NAFLD patients with advanced neoplasms had isolated lesions in the right sided colon. Among patients with biopsy proven NAFLD, patients with non-alcoholic steatohepatitis (N=49) had a higher prevalence of adenomas (51.0% vs 25.6%; p=0.005) and advanced neoplasms (34.7% vs 14.0%; p=0.011) than those with simple steatosis (N=86). After adjusting for demographic and metabolic factors, non-alcoholic steatohepatitis remained associated with adenomas (adjusted OR 4.89, 95% CI 2.04 to 11.70) and advanced neoplasms (OR 5.34, 95% CI 1.92 to 14.84). In contrast, the prevalence of adenomas and advanced neoplasms was similar between patients with simple steatosis and control subjects.ConclusionsNon-alcoholic steatohepatitis is associated with a high prevalence of colorectal adenomas and advanced neoplasms. The adenomas are found more commonly in the right sided colon. Colorectal cancer screening is strongly indicated in this high risk group.
We report new infrared radial velocity measurements obtained with CSHELL at NASA's Infrared Telescope Facility that reveal the M3.5 dwarf GJ 867B to be a single-lined spectroscopic binary with a ...period of 1.795+ or -0.017 days. Its velocity semi-amplitude of 21.4+ or -0.5 km s super(-1) corresponds to a minimum mass of 61 + or - 7 M sub(JUP); the new companion, which we call GJ 867D, could be a brown dwarf. Stable astrometric measurements of GJ 867BD obtained with CTIO's 0.9 m telescope over the last decade exclude the presence of any massive planetary companions (7-18 M sub(JUP)) with longer orbital periods (2-10 yr) for the majority of orientations. These complementary observations are also used to determine the trigonometric distance and proper motion of GJ 867BD; the measurements are consistent with the HIPPARCOS measured values of the M2 dwarf GJ 867AC, which is itself a 4.1 day double-lined spectroscopic binary at a projected separation of 24".5 (216 AU) from GJ 867BD. These new measurements strengthen the case that GJ 867AC and GJ 867BD are physically associated, making the GJ 867 system one of only four quadruple systems within 10 pc of the Sun (d = 8.82 + or - 0.08 pc) and the only among these with all M-dwarf (or cooler) components.
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