ABSTRACT
We present the discovery of only the third brown dwarf known to eclipse a non-accreting white dwarf. Gaia parallax information and multicolour photometry confirm that the white dwarf is cool ...(9950 ± 150 K) and has a low mass (0.45 ± 0.05 M⊙), and spectra and light curves suggest the brown dwarf has a mass of 0.067 ± 0.006 M⊙ (70MJup) and a spectral type of L5 ± 1. The kinematics of the system show that the binary is likely to be a member of the thick disc and therefore at least 5-Gyr old. The high-cadence light curves show that the brown dwarf is inflated, making it the first brown dwarf in an eclipsing white dwarf-brown dwarf binary to be so.
ABSTRACT
V341 Ara was recently recognized as one of the closest (d ≃ 150 pc) and brightest (V ≃ 10) nova-like cataclysmic variables. This unique system is surrounded by a bright emission nebula, ...likely to be the remnant of a recent nova eruption. Embedded within this nebula is a prominent bow shock, where the system’s accretion disc wind runs into its own nova shell. In order to establish its fundamental properties, we present the first comprehensive multiwavelength study of the system. Long-term photometry reveals quasi-periodic, super-orbital variations with a characteristic time-scale of 10–16 d and typical amplitude of ≃1 mag. High-cadence photometry from theTransiting Exoplanet Survey Satellite (TESS) reveals for the first time both the orbital period and a ‘negative superhump’ period. The latter is usually interpreted as the signature of a tilted accretion disc. We propose a recently developed disc instability model as a plausible explanation for the photometric behaviour. In our spectroscopic data, we clearly detect antiphased absorption and emission-line components. Their radial velocities suggest a high mass ratio, which in turn implies an unusually low white-dwarf mass. We also constrain the wind mass-loss rate of the system from the spatially resolved O iii emission produced in the bow shock; this can be used to test and calibrate accretion disc wind models. We suggest a possible association between V341 Ara and a ‘guest star’ mentioned in Chinese historical records in AD 1240. If this marks the date of the system’s nova eruption, V341 Ara would be the oldest recovered nova of its class and an excellent laboratory for testing nova theory.
This is a prospective randomized study to analyze results obtained in two groups of patients, affected by stage 2 rectocele and treated with rectum anterior wall repair and strength, performed with ...standard or modified Khubchandani technique, using High Frequency (HF) Radio Scalpel.
A cohort of 24 patients with stage 2 rectocele (Mellgren's classification) have been included. Twelve (group A) underwent surgery with standard technique and twelve (group B) underwent surgery using the HF Radio Scalpel, which cuts and coagulates tissues without damage thanks to its low working temperature (45-70°C). Each patient underwent proctolo-gical examination and anoscopy in 7th, 15th, 45th POD and after 6 and 12 months.
During post-operative follow-up 5 patients from group A and 1 from group B didn't show up so that they drop out the study. As a result, group A is composed by 7 patients and group B by 11 patients. Mean operating time was significantly favourable in group B (51 vs 33 minutes, p< 0.01). The differences between other parameters weren't statistically significant, even if post-operative course was less difficult in HF Radio Scalpel group.
The surgical technique to repair and reinforce anterior rectal wall is easier and faster if performed with HF Radio Scalpel respect to the standard procedure described by Khubchandani. Post-operative course was less painful and, even more importantly considering the patient age, surgical time was shorter. Therefore, the results obtained cast positive light on using this technique to treat uncomplicated grade 2 rectocele.
This is a prospective randomized study to analyze results obtained in two groups of patients, affected by stage 2 rectocele and treated with rectum anterior wall repair and strength, performed with ...standard or modified Khubchandani technique, using High Frequency (HF) Radio Scalpel.
A cohort of 24 patients with stage 2 rectocele (Mellgren's classification) have been included. Twelve (group A) underwent surgery with standard technique and twelve (group B) underwent surgery using the HF Radio Scalpel, which cuts and coagulates tissues without damage thanks to its low working temperature (45-70°C). Each patient underwent proctolo-gical examination and anoscopy in 7th, 15th, 45th POD and after 6 and 12 months.
During post-operative follow-up 5 patients from group A and 1 from group B didn't show up so that they drop out the study. As a result, group A is composed by 7 patients and group B by 11 patients. Mean operating time was significantly favourable in group B (51 vs 33 minutes, p< 0.01). The differences between other parameters weren't statistically significant, even if post-operative course was less difficult in HF Radio Scalpel group.
The surgical technique to repair and reinforce anterior rectal wall is easier and faster if performed with HF Radio Scalpel respect to the standard procedure described by Khubchandani. Post-operative course was less painful and, even more importantly considering the patient age, surgical time was shorter. Therefore, the results obtained cast positive light on using this technique to treat uncomplicated grade 2 rectocele.
We report the discovery of two new transiting giant exoplanets NGTS-26 b and NGTS-27 b by the Next Generation Transit Survey (NGTS). NGTS-26 b orbits around a G6-type main sequence star every 4.52 ...days. It has a mass of 0.29 -0.06 +0.07 M Jup and a radius of 1.33 -0.05 +0.06 R Jup making it a Saturn-mass planet with a highly inflated radius. NGTS-27 b orbits around a slightly evolved G3-type star every 3.37 days. It has a mass of 0.59 -0.07 +0.10 M Jup and a radius of 1.40±0.04 R Jup , making it a relatively standard hot Jupiter. The transits of these two planetary systems were re-observed and confirmed in photometry by the SAAO 1.0-m telescope, 1.2-m Euler Swiss telescope as well as the TESS spacecraft, and their masses were derived spectroscopically by the CORALIE, FEROS and HARPS spectrographs. Both giant exoplanets are highly irradiated by their host stars and present an anomalously inflated radius, especially NGTS-26 b which is one of the largest objects among peers of similar mass.
Context.
The sub-Jovian, or Neptunian, desert is a previously identified region of parameter space where there is a relative dearth of intermediate-mass planets with short orbital periods.
Aims.
We ...present the discovery of a new transiting planetary system within the Neptunian desert, NGTS-14.
Methods.
Transits of NGTS-14Ab were discovered in photometry from the Next Generation Transit Survey (NGTS). Follow-up transit photometry was conducted from several ground-based facilities, as well as extracted from TESS full-frame images. We combine radial velocities from the HARPS spectrograph with the photometry in a global analysis to determine the system parameters.
Results.
NGTS-14Ab has a radius that is about 30 per cent larger than that of Neptune (0.444 ± 0.030
R
Jup
) and is around 70 per cent more massive than Neptune (0.092 ± 0.012
M
Jup
). It transits the main-sequence K1 star, NGTS-14A, with a period of 3.54 days, just far away enough to have maintained at least some of its primordial atmosphere. We have also identified a possible long-period stellar mass companion to the system, NGTS-14B, and we investigate the binarity of exoplanet host stars inside and outside the Neptunian desert using
Gaia
.
We present the discovery of only the third brown dwarf known to eclipse a non-accreting white dwarf. Gaia parallax information and multi-colour photometry confirm that the white dwarf is cool ...(9950\(\pm\)150K) and has a low mass (0.45\(\pm\)0.05~MSun), and spectra and lightcurves suggest the brown dwarf has a mass of 0.067 \(\pm\)0.006 MSun (70 MJup) and a spectral type of L5 \(\pm\)1. The kinematics of the system show that the binary is likely to be a member of the thick disk and therefore at least 5 Gyr old. The high cadence lightcurves show that the brown dwarf is inflated, making it the first brown dwarf in an eclipsing white dwarf-brown dwarf binary to be so.
Context: The sub-Jovian or Neptunian desert is a previously-identified region of parameter space where there is a relative dearth of intermediate-mass planets at short orbital periods. Aims: We ...present the discovery of a new transiting planetary system within the Neptunian desert, NGTS-14. Methods: Transits of NGTS-14Ab were discovered in photometry from the Next Generation Transit Survey (NGTS). Follow-up transit photometry was conducted from several ground-based facilities, as well as extracted from TESS full-frame images. We combine radial velocities from the HARPS spectrograph with the photometry in a global analysis to determine the system parameters. Results: NGTS-14Ab has a radius about 30 per cent larger than that of Neptune (\(0.444\pm0.030~\mathrm{R_{Jup}}\)), and is around 70 per cent more massive than Neptune (\(0.092 \pm 0.012~\mathrm{M_{Jup}}\)). It transits the main-sequence K1 star, NGTS-14A, with a period of 3.54 days, just far enough to have maintained at least some of its primordial atmosphere. We have also identified a possible long-period stellar mass companion to the system, NGTS-14B, and we investigate the binarity of exoplanet host stars inside and outside the Neptunian desert using Gaia.
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