Context. With an orbital distance comparable to that of Saturn in the solar system, β Pictoris b is the closest (semi-major axis ≃9 au) exoplanet that has been imaged to orbit a star. Thus it offers ...unique opportunities for detailed studies of its orbital, physical, and atmospheric properties, and of disk-planet interactions. With the exception of the discovery observations in 2003 with NaCo at the Very Large Telescope (VLT), all following astrometric measurements relative to β Pictoris have been obtained in the southwestern part of the orbit, which severely limits the determination of the planet’s orbital parameters. Aims. We aimed at further constraining β Pictoris b orbital properties using more data, and, in particular, data taken in the northeastern part of the orbit. Methods. We used SPHERE at the VLT to precisely monitor the orbital motion of beta β Pictoris b since first light of the instrument in 2014. Results. We were able to monitor the planet until November 2016, when its angular separation became too small (125 mas, i.e., 1.6 au) and prevented further detection. We redetected β Pictoris b on the northeast side of the disk at a separation of 139 mas and a PA of 30° in September 2018. The planetary orbit is now well constrained. With a semi-major axis (sma) of a = 9.0 ± 0.5 au (1σ), it definitely excludes previously reported possible long orbital periods, and excludes β Pictoris b as the origin of photometric variations that took place in 1981. We also refine the eccentricity and inclination of the planet. From an instrumental point of view, these data demonstrate that it is possible to detect, if they exist, young massive Jupiters that orbit at less than 2 au from a star that is 20 pc away.
We report the discovery of a bright, brown dwarf companion to the star HIP 64892, imaged with VLT/SPHERE during the SHINE exoplanet survey. The host is a B9.5V member of the Lower-Centaurus-Crux ...subgroup of the Scorpius Centaurus OB association. The measured angular separation of the companion (1.2705 ± 0.0023”) corresponds to a projected distance of 159 ± 12 AU. We observed the target with the dual-band imaging and long-slit spectroscopy modes of the IRDIS imager to obtain its spectral energy distribution (SED) and astrometry. In addition, we reprocessed archival NACO L-band data, from which we also recover the companion. Its SED is consistent with a young (<30 Myr), low surface gravity object with a spectral type of M9γ ± 1. From comparison with the BT-Settl atmospheric models we estimate an effective temperature of Teff = 2600 ± 100 K, and comparison of the companion photometry to the COND evolutionary models yields a mass of ~29−37 MJ at the estimated age of 16−7+15 $16^{+15}_{-7}$16−7+15 Myr for the system. The star HIP 64892 is a rare example of an extreme-mass ratio system (q ~ 0.01) and will be useful for testing models relating to the formation and evolution of such low-mass objects.
To investigate adrenocorticotropin, androstenedione (ASD), cortisol, or dehydroepiandrosterone sulfate (DHEAS) before and during a corticotropin releasing hormone (hCRH) test in patients with ...moderately active systemic lupus erythematosus (SLE) undergoing low dose longterm glucocorticoid therapy, and to examine these hormones in relation to interleukin 6 (IL-6) or tumor necrosis factor (TNF).
Serum levels of hormones and cytokines were measured before and during an hCRH test. The results of 12 patients with SLE were compared to 12 healthy subjects (HS) and 12 healthy subjects given prior short term prednisolone (HS+P).
Baseline and stimulated serum ASD, cortisol, and DHEAS were lower in patients with SLE vs. HS (p<0.005), but baseline and stimulated plasma adrenocorticotropin was normal in SLE. In SLE, but not in HS+P or HS, baseline and stimulated DHEAS was low in relation to cortisol or ASD (i.e., shift from DHEAS to cortisol or ASD). In patients with SLE, baseline and stimulated serum levels of adrenal hormones were lower in relation to IL-6 or TNF compared to HS or HS+P (p< 0.001). In contrast, in SLE patients, the baseline and stimulated pituitary hormone adrenocorticotropin was normal in relation to these cytokines.
We found marked adrenal insufficiency and a shift in steroidogenesis to cortisol in patients with SLE, but a completely normal pituitary function (in absolute values and in relation to IL-6 or TNF). This may depend in part on prior longterm glucocorticoid therapy and changes of steroidogenesis due to cytokines. The situation in patients with SLE was not mimicked by high dose short term prednisolone in healthy subjects. Further longitudinal studies in untreated patients are needed to investigate the endocrine-immune interplay and its consequences during the course of SLE.
To determine the human corticotropin releasing hormone (hCRH) induced stress response of the hypothalamus-autonomic nervous system axis (HANS) in patients with moderately active systemic lupus ...erythematosus (SLE).
Cardiovascular and pupillary function variables were measured by standardized computer procedures before and during an hCRH test (6 time points). The results of 12 patients with SLE were compared to 24 healthy subjects with (HS+P, n = 12) and without (HS, n = 12) prior administration of prednisolone 3 days before the test.
At baseline, diastolic blood pressure was significantly higher in SLE than in HS or HS+P (p<0.001). During the hCRH test, patients with SLE had increased heart rates and systolic and diastolic blood pressure responses compared to HS+P and HS (p<0.001 for all comparisons). Moreover, heart rate variation was decreased at rest, during the lying-to-standing procedure, and during the 2 applied respiratory tests (p<0.01 vs. HS). Compared to HS+P and HS, latency time of the pupillary light reflex was prolonged and maximal pupillary area was increased, revealing sympathetic hyperreactivity.
This study found an altered autonomic nervous system response at baseline, which was more pronounced during the hCRH stress test in patients with moderately active SLE compared to healthy subjects. Baseline and stress responses are characterized by a sympathetic overstimulation. Such a hypersympathetic reaction may lead to increased risk of cardiovascular diseases in patients with moderately active SLE, which needs to be investigated in longitudinal studies.
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