scholarly journals Long-term spectroscopic monitoring of LBVs and LBV candidates

2010 ◽  
Vol 6 (S272) ◽  
pp. 519-520
Author(s):  
Alex Lobel ◽  
Jose H. Groh ◽  
Kelly Torres ◽  
Nadya Gorlova
Keyword(s):  
Radial Velocity ◽  
Monitoring Program ◽  
Echelle Spectrograph ◽  
Luminous Blue Variables ◽  
Spectroscopic Monitoring ◽  
La Palma ◽  
Lower Excitation Energy ◽  
Lower Excitation ◽  
Hα Emission

AbstractWe present results of a long-term spectroscopic monitoring program (since mid 2009) of Luminous Blue Variables with the new HERMES echelle spectrograph on the 1.2m Mercator telescope at La Palma (Spain). We investigate high-resolution (R = 80,000) optical spectra of two LBVs, P Cyg and HD 168607, the LBV candidates MWC 930 and HD 168625, and the LBV binary MWC 314. In P Cyg we observe flux changes in the violet wings of the Balmer Hα, Hβ, and He i lines between May and Sep 2009. The changes around 200 to 300 km s−1 are caused by variable opacity at the base of the supersonic wind from the blue supergiant.We observe in MWC 314 broad double-peaked metal emission lines with invariable radial velocities over time. On the other hand, we measure in the photospheric S ii λ5647 absorption line, with lower excitation energy of ~14 eV, an increase of the heliocentric radial velocity centroid from 37 km s−1 to 70 km s−1 between 5 and 10 Sep 2009 (and 43 km s−1 on 6 Apr 2010). The increase of radial velocity of ~33 km s−1 in only 5 days can confirm the binary nature of this LBV close to the Eddington luminosity limit.A comparison with VLT-UVES and Keck-Hires spectra observed over the past 13 years reveals strong flux variability in the violet wing of the Hα emission line of HD 168625 and in the absorption portion of the Hβ line of HD 168607. In HD 168625 we observe Hα wind absorption at velocities exceeding 200 km s−1 which develops between Apr and June 2010.

scholarly journals Precise Radial Velocity Measurements with a Cassegrain Spectrograph, I: Wavelength calibration

1999 ◽  
Vol 170 ◽  
pp. 63-67
Author(s):  
I. V. Ilyin ◽  
R. Duemmler
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Cross Correlation ◽  
Time Dependent ◽  
Instrumental Effects ◽  
Velocity Measurements ◽  
Echelle Spectrograph ◽  
Optical Telescope ◽  
La Palma ◽  
Observational Strategy

AbstractWe briefly describe the instrumental effects which affect the accuracy of the radial velocity measurements. We have implemented several methods to correct for the instability effects and improve the accuracy of the measurements. These include modifications of the observational strategy and a time-dependent wavelength solution as well as a discussion of the error of the offset from cross-correlation. These methods are applied to observations obtained with the high resolution échelle spectrograph SOFIN mounted at the Cassegrain focus of the alt-azimuth 2.56-m Nordic Optical Telescope, La Palma, Canary Islands.

scholarly journals Absolute Parameter Determination in Low-Mass Eclipsing Binaries. Radiative Parameters for BH VIR, ZZ UMa and CR Cas

1993 ◽  
Vol 137 ◽  
pp. 386-391
Author(s):  
R. Clement ◽  
V. Reglero ◽  
M. Garcia ◽  
J. Fabregat ◽  
A. Bravo ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Monitoring Program ◽  
Mass Range ◽  
Eclipsing Binaries ◽  
Radiative Properties ◽  
Parameter Determination ◽  
Low Mass ◽  
Observational Program

AbstractA new uvby and Hβ monitoring program of low mass eclipsing binaries is currently being carried out in the framework of a 5 year observational program which also involves radial velocity determinations. The scope of this work is to provide very accurate absolute astrophysical parameters: mass, radius and effective temperatures, for main sequence late-type stars. One of the main goals is to improve the mass-luminosity relation in the low and intermediate mass range. A second objective is to perform accurate tests of the most recent grids of evolutionary models. This program is complementary to that currently being in progresss by the Copenhagen group.In this contribution we present the photometric preliminary results obtained for three of the systems included in our long term survey: BH Vir, ZZ UMa and CR Cas for which, primary eclipses have been observed. Particular attention is paid to the determination of reddening, distances and radiative properties. A more detailed study will be carried out when the light curves and radial velocity measurements are completed

scholarly journals High-resolution spectroscopy of two LBV cycles of HR Car

2003 ◽  
Vol 212 ◽  
pp. 243-244 ◽  
Author(s):  
Thomas Szeifert ◽  
Andreas Kaufer ◽  
Paul A. Crowther ◽  
Otmar Stahl ◽  
Chris Sterken
Keyword(s):  
High Resolution ◽  
Stellar Wind ◽  
Optical Spectra ◽  
High Resolution Spectroscopy ◽  
Luminous Blue Variables ◽  
Wide Part ◽  
Spectroscopic Monitoring ◽  
Wind Characteristics ◽  
Long Timescales

Luminous Blue Variables (LBVs or S Dor Variables) are showing characteristic variability of very long timescales of a decade and more. During their expansion and contraction phases, they move across a wide part of the H-R diagram with dramatic changes of their stellar wind characteristics, radius and temperature. We present results of our long-term spectroscopic monitoring campaigns for the galactic star HR Car with optical spectra taken over 13 years and two minimum and maximum phases observed during this time.

Opioid Consumption Patterns and Prolonged Opioid Use Among Opioid-Naïve Ankle Fracture Patients

2021 ◽  
pp. 193864002199292
Author(s):  
Hope Skibicki ◽  
Sundeep Saini ◽  
Ryan Rogero ◽  
Kristen Nicholson ◽  
Rachel J. Shakked ◽  
...  
Keyword(s):  
Ankle Fracture ◽  
Monitoring Program ◽  
Opioid Consumption ◽  
Consumption Patterns ◽  
Utilization Rate ◽  
Opioid Use ◽  
Index Procedure ◽  
Postoperative Visit ◽  
Fracture Surgery

Introduction Previous literature has demonstrated an association between acute opioid exposure and the risk of long-term opioid use. Here, the investigators assess immediate postoperative opioid consumption patterns as well as the incidence of prolonged opioid use among opioid-naïve patients following ankle fracture surgery. Methods Included patients underwent outpatient open reduction and internal fixation of an ankle or tibial plafond fracture over a 1-year period. At patients’ first postoperative visit, opioid pills were counted and standardized to the equivalent number of 5-mg oxycodone pills. Prolonged use was defined as filling a prescription for a controlled substance more than 90 days after the index procedure, tracked by the New Jersey Prescription Drug Monitoring Program up to 1 year postoperatively. Results At the first postoperative visit, 173 patients consumed a median of 24 out of 40 pills prescribed. The initial utilization rate was 60%, and 2736 pills were left unused. In all, 32 (18.7%) patients required a narcotic prescription 90 days after the index procedure. Patients with a self-reported history of depression (P = .11) or diabetes (P = .07) demonstrated marginal correlation with prolonged narcotic use. Conclusion Our study demonstrated that, on average, patients utilize significantly fewer opioid pills than prescribed and that many patient demographics are not significant predictors of continued long-term use following outpatient ankle fracture surgery. Large variations in consumption rates make it difficult for physicians to accurately prescribe and predict prolonged narcotic use. Level of Evidence: Level III

scholarly journals R Coronae Borealis Stars: Long-Term Photometric & Spectroscopic Studies

1998 ◽  
Vol 11 (1) ◽  
pp. 379-379
Author(s):  
P.L. Cottrell ◽  
L. Skuljan ◽  
P.M. Kilmartin ◽  
C. Gilmore ◽  
W.A. Lawson
Keyword(s):  
Radial Velocity ◽  
Spectroscopic Studies ◽  
Photometric Data ◽  
Decline Phase ◽  
Dust Clouds ◽  
Medium Resolution ◽  
Formation And Evolution ◽  
R Coronae Borealis Stars ◽  
Insight Into

For more than a decade we have been able to acquire and analyse a significant amount of photometric data of the highly variable R Coronae Borealis (RCB) stars. This has made been possible by a photometric service observing programme instigated at the Observatory. These photometric data have been combined with less extensive spectroscopic coverage, particularly of the decline phase of these stars. These have been supplemented by observations obtained at Mount Stromlo and Siding Spring Observatories for a radial velocity study. Significantly more spectroscopic observations are now being acquired with the development of a new medium resolution spectrograph at Mount John University Observatory. In this poster we will present recent photometric and spectroscopic results for a number of the RCB stars in our sample. This observational and analysis work can be used to provide further insight into the nature of these stars, their likely progeny and progenitors and the processes that are involved in the formation and evolution of the obscuring dust clouds which cause the decline phase.

scholarly journals Long-Term Coudé Radial-Velocity Studies With a 1.2-m Telescope

2001 ◽  
Vol 183 ◽  
pp. 283-288
Author(s):  
C.D. Scarfe
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Star System ◽  
Standard Star ◽  
Stellar Spectra ◽  
Multiple Stars ◽  
Binary And Multiple Stars ◽  
Selection Of

AbstractI have used the 1.2-m telescope and coudé spectrograph of the Dominion Astrophysical Observatory for more than 30 years in a program of radial-velocity observations of binary stars. The program was begun with photographic plates as detectors, but for 20 years the primary detector has been the radial-velocity scanner, which cross-correlates stellar spectra with an artificial mask.Since some of the binaries under observation have periods of several years, the instrument’s stability is an important consideration. I have therefore been obliged to observe standard stars and asteroids to check its performance. These observations are of relevance to efforts to improve the IAU standard star system.I will describe the telescope, spectrograph and scanner, and will briefly discuss some of the results obtained for a selection of binary and multiple stars.

scholarly journals Light curve analysis of the late type binary V523 Cassiopeiae

2009 ◽  
pp. 45-48 ◽  
Author(s):  
O. Latkovic ◽  
M. Zboril ◽  
G. Djurasevic
Keyword(s):  
Light Curve ◽  
Monitoring Program ◽  
Neck Region ◽  
Bright Spot ◽  
Late Type ◽  
Light Curve Analysis ◽  
Type Contact ◽  
Contact Binary ◽  
Previous Solution

We present the analysis of V and R light curves of the late type contact binary V523 Cas for the season of 2006. These observations make part of the monitoring program aimed at studying the long-term light curve variability in this system. Our results confirm that the system is in an over contact configuration, and include a bright spot in the neck region of the cooler and larger primary. We compare these results with the previous solution, obtained for the season 2005 dataset and discuss the differences.

Distribution and Abundance of Odonata Species Across Massachusetts: Results of a Long-term Monitoring Program

2016 ◽  
Vol 23 (4) ◽  
pp. 501-524 ◽  
Author(s):  
Robert Buchsbaum ◽  
Christopher W. Leahy ◽  
Taber Allison
Keyword(s):  
Monitoring Program ◽  
Long Term Monitoring ◽  
Term Monitoring
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