scholarly journals Two temperate sub-Neptunes transiting the star EPIC 212737443

2019 ◽  
Vol 488 (1) ◽  
pp. 536-546
Author(s):  
Mahesh Herath ◽  
Tobias C Hinse ◽  
John H Livingston ◽  
Jesús Hernández ◽  
Daniel F Evans ◽  
...  

ABSTRACT We report the validation of a new planetary system around the K3 star EPIC 212737443 using a combination of K2 photometry, follow-up high-resolution imaging and spectroscopy. The system consists of two sub-Neptune sized transiting planets with radii of 2.6R⊕ and 2.7R⊕, with orbital periods of 13.6 and 65.5 d, equilibrium temperatures of 536 and 316 K, respectively. In the context of validated K2 systems, the outer planet has the longest precisely measured orbital period, as well as the lowest equilibrium temperature for a planet orbiting a star of spectral type earlier than M. The two planets in this system have a mutual Hill radius of ΔRH  = 36, larger than most other known transiting multiplanet systems, suggesting the existence of another (possibly non-transiting) planet, or that the system is not maximally packed.

2006 ◽  
Vol 2 (S235) ◽  
pp. 301-301
Author(s):  
Luciana Bianchi ◽  
David Thilker ◽  
Armando Gil de Paz ◽  
Barry Madore ◽  

AbstractMotivated by the GALEX discovery of recent star formation in outermost regions of M83 and NGC4625, we have investigated the nature of the XUV disks with follow-up high resolution imaging and spectroscopy, and attempted to detect them at other wavelengths (IR, Hα). We searched for additional XUV-disk galaxies in the local universe, in order to quantify the incidence of the XUV-disk phenomenon, infer the causes of such extended star formation (SF), and place these systems in the context of disk galaxy evolution.


2019 ◽  
Vol 28 (8) ◽  
pp. 1171-1180 ◽  
Author(s):  
Marie-Hélène Errera ◽  
Marthe Laguarrigue ◽  
Florence Rossant ◽  
Edouard Koch ◽  
Céline Chaumette ◽  
...  

Nano Letters ◽  
2014 ◽  
Vol 14 (10) ◽  
pp. 5517-5523 ◽  
Author(s):  
Jérôme Martin ◽  
Mathieu Kociak ◽  
Zackaria Mahfoud ◽  
Julien Proust ◽  
Davy Gérard ◽  
...  

Neurosurgery ◽  
2004 ◽  
Vol 55 (1) ◽  
pp. 100-107 ◽  
Author(s):  
Paul Park ◽  
William F. Chandler ◽  
Ariel L. Barkan ◽  
John J. Orrego ◽  
John A. Cowan ◽  
...  

Abstract OBJECTIVE: Radiotherapy after aggressive surgical resection of nonfunctional macroadenoma (NFA) of the pituitary remains controversial. Historically, immediate postoperative radiotherapy has been recommended to decrease risk of recurrence. With the availability of high-resolution imaging, most neurosurgeons now withhold radiation until recurrence. There is relatively little evidence to support this practice, however. This study reviews postoperative results in a large number of patients with NFA, the majority of whom did not undergo prophylactic radiation. METHODS: Of the 258 patients who underwent surgery from 1979 to 1999 for NFA, medical records were available for 176. Forty-four patients were treated with immediate postoperative radiotherapy after tumor resection, and the remaining 132 patients were followed up with serial imaging studies and treated with radiotherapy only when a recurrence was documented by follow-up imaging. RESULTS: Patients in the group that received immediate postoperative radiotherapy at time of initial diagnosis and surgery did not differ significantly with respect to age or sex from those in the group that was observed. Five- and 10-year recurrence rates were 2.3 and 2.3%, respectively, for patients who received immediate postoperative radiotherapy, as compared with 15.2 and 50.5%, respectively, for patients who were followed up and did not receive radiotherapy unless there was evidence of recurrence or progression. No patient had symptomatic recurrence in the group that was observed if consistent follow-up was performed. Of the 26 patients who received radiotherapy at time of tumor recurrence or progression, 18 had adequate follow-up, and in all cases, the tumors either remained stable or regressed. CONCLUSION: Withholding radiotherapy after a high-percentage resection of NFA leads to a higher recurrence rate, but it avoids exposing all patients to the risks of radiation. Deferring radiotherapy for patients with complete or near-complete resection seems to be a safe and prudent approach, as our data suggest that recurrences may be detected early with high-resolution imaging and treated effectively with radiation at time of recurrence. Therefore, immediate postoperative radiotherapy may be eliminated for patients with complete or near complete resection of NFA and who agree to undergo close follow-up for a long period.


2021 ◽  
Vol 11 (14) ◽  
pp. 6261
Author(s):  
Andrew Rakich

Atmospheric dispersion produces spectral elongation in images formed by land-based astronomical telescopes, and this elongation increases as the telescope points away from the zenith. Atmospheric Dispersion Correctors (ADCs) produce compensating dispersion that can be adjusted to best cancel out the atmospheric effect. These correctors are generally of two basic types: Rotating Atmospheric Dispersion Correctors (R-ADCs), and Linear Atmospheric Dispersion Correctors (L-ADCs). Lately, a third type, the “Compensating Lateral ADC” (CL-ADC) has been proposed. None of these design approaches allow for large corrector systems (with elements greater than 1 m in diameter), in which the secondary spectrum is corrected to small residuals, of the order of tens’ of milliarcseconds. This paper describes a new type of large corrector (>1 m diameter elements), which can achieve the correction of the secondary spectrum to the order of 10 milliarcseconds. This correction is achieved by combining the R-ADC and CL-ADC approaches to dispersion correction. Only glass types readily available in metre diameters are required.


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