93 research outputs found
V2494 cyg: A unique FU ori type object in the cygnus OB7 complex
A photometric and spectral study of the variable star V2494 Cyg in the L 1003 dark cloud is presented. The brightness of the star, formerly known as HH 381 IRS, increased by 2.5 mag in R (probably in the 1980s) and since then has remained nearly constant. Since the brightness increase, V2494 Cyg has illuminated a bipolar cometary nebula. The stellar spectrum has several features typical of the FU Ori (FUor) type, plus it exhibits very strong Ha and forbidden emissionlines with high-velocity components. These emission lines originate in the Herbig-Haro (HH) jet near the star. The kinematic age of the jet is consistent with it forming at the time of the outburst leading to the luminosity increase. V2494 Cyg also produces a rather extended outflow; it is the first known FUor with both an observed outburst and a parsec-sized HH flow. The nebula, illuminated by V2494 Cyg, possesses similar morphological and spectral characteristics to Hubble's variable nebula (R Monocerotis/NGC 2261). © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
Kinematics and the origin of the internal structures in HL Tau jet (HH 151)
Knotty structures of Herbig-Haro jets are common phenomena, and knowing the
origin of these structures is essential for understanding the processes of jet
formation. Basically, there are two theoretical approaches: different types of
instabilities in stationary flow, and velocity variations in the flow. We
investigate the structures with different radial velocities in the knots of the
HL Tau jet as well as its unusual behaviour starting from 20 arcsec from the
source. Collation of radial velocity data with proper motion measurements of
emission structures in the jet of HL Tau makes it possible to understand the
origin of these structures and decide on the mechanism for the formation of the
knotty structures in Herbig-Haro flows. We present observations obtained with a
6 m telescope (Russia) using the SCORPIO camera with scanning Fabry-Perot
interferometer. Two epochs of the observations of the HL/XZ Tau region in
Halpha emission (2001 and 2007) allowed us to measure proper motions for high
and low radial velocity structures. The structures with low and high radial
velocities in the HL Tau jet show the same proper motion. The point where the
HL Tau jet bents to the north (it coincides with the trailing edge of so-called
knot A) is stationary, i.e. does not have any perceptible proper motion and is
visible in Halpha emission only. We conclude that the high- and low- velocity
structures in the HL Tau jet represent bow-shocks and Mach disks in the
internal working surfaces of episodic outflows. The bend of the jet and the
brightness increase starting some distance from the source coincides with the
observed stationary deflecting shock. The increase of relative surface
brightness of bow-shocks could be the result of the abrupt change of the
physical conditions of the ambient medium as well as the interaction of a
highly collimated flow and the side wind from XZ Tau.Comment: To be published in Astronomy and Astrophysic
New powerful outburst of the unusual young star V1318 Cyg S (LkH{\alpha} 225)
Young double star V1318 Cyg, which is associated with a small isolated
star-forming region around HAeBe star BD+40o4124, has very unusual photometric
and spectral behavior. We present results of photometric and spectroscopic
observations in the optical range. We carried out BVRI CCD photometric
observations of V1318 Cyg from 2015 Sept. to 2017 July. For the same period we
acquired medium- and low-resolution spectra. Observations were performed with
the 2.6 m telescope. We analyze the historical light curve for V1318 Cyg and
demonstrate that the southern component, V1318 Cyg S, after being rather bright
in the 1970s (V14 mag) started to lower its brightness and in 1990
became practically invisible in the optical. After its reappearance in the
second half of the 1990s the star started to become very slowly brighter.
Between 2006 and 2010 V1318 Cyg S started brightening more quickly, and in 2015
had become brighter by more than five magnitudes in visible light. Since this
time V1318 Cyg S has remained at this maximum. Its spectrum shows little
variability and consists of a mixture of emission and absorption lines, which
has allowed for estimates of its spectral type as early Ae, with obvious
evidence of matter outflow. We derive its current A(V) 7.2 and L = 750
L(sun) thus confirming that V1318 Cyg S should belong to the Herbig Ae stars,
making it, along with BD+40o4124 and V1686 Cyg, the third luminous young star
in the group. It is very probable that we observe V1318 Cyg S near the pole and
that the inclination of its dense and slow ( 100 km/s) outflow is low.
The unusual variability and other features of V1318 Cyg S make it difficult to
classify this star among known types of eruptive young stars. It could be an
extreme, higher-mass example of an EXor, or an object of intermediate class
between EXors and FUors, like V1647 Ori.Comment: 9 pages, 7 figure
Association Between Therapeutic Interventions and Quality of Life in People With Autism
Research exploring the association of autism interventions with the quality of life (QoL) of adults with autism spectrum disorders was scarce. Although a multitude of interventions are used to target a specific challenge facing the individual with autism, their correlation with achieving a better QoL is largely unknown. We conducted a cross-sectional, correlational survey study to determine the association between seven interventions—behavioral, social, mental health, daily living skills (DLS), vocational, mindfulness, and medications—and the QoL of adults 18 years and older with autism with no intellectual disability (ID) living in Canada. A national sample of 182 autistic adults or proxy reports completed the survey that used the WHOQOL-BREF to measure subjective QoL. Behavioral, mental health, and medications were the most frequently used interventions (67%, 71.4%, and 82.4%, respectively). QoL was lower across all domains of the WHOQOL-BREF compared with the general population. Hierarchical multiple regression analysis showed that characteristics, such as autism severity, being female, and older age negatively predicted QoL across all domains except for the physical domain, whereas being in a relationship positively predicted social QoL explaining 35.2% of the variance. Of the seven interventions used, behavioral therapies and receiving mental health support consistently predicted a better QoL across all domains, except for the environment domain where only mental health support was a significant predictor. Our findings suggest prioritizing provision of behavioral and mental health interventions to adults with autism and inform future research to evaluate their effectiveness in QoL outcomes as an end goal
Discovery Of A Molecular Outflow in the Haro 6-10 Star-Forming Region
We present high sensitivity 12CO and 13CO (1-0) molecular line maps covering
the full extent of the parsec scale Haro~6-10 Herbig-Haro (HH) flow. We report
the discovery of a molecular CO outflow along the axis of parsec-scale HH flow.
Previous molecular studies missed the identification of the outflow probably
due to their smaller mapping area and the confusing spectral features present
towards the object. Our detailed molecular line study of the full 1.6 pc extent
of the optical flow shows evidence for both blueshifted and redshifted gas set
in motion by Haro~6-10 activity. The molecular outflow is centered at
Haro~6-10, with redshifted gas being clumpy and directed towards the northeast,
while blueshifted gas is in the southwest direction. The molecular gas
terminates well within the cloud, short of the most distant HH objects of the
optical flow. Contamination from an unrelated cloud along the same line of
sight prevents a thorough study of the blueshifted outflow lobe and the mass
distribution at the lowest velocities in both lobes. The cloud core in which
Haro~6-10 is embedded is filamentary and flattened in the east-west direction.
The total cloud mass is calculated from 13CO(1-0) to be ~200Msun. The lower
limit of the mass associated with the outflow is ~0.25Msun.Comment: ApJ Accepted; 9 pages, 8 figures. For high resolution ps file use:
http://www.astro.umass.edu/~irena/haro.p
Association Between Therapeutic Interventions and Quality of Life in People with Autism
Research exploring the impact of autism interventions on the quality of life (QoL) of adults with autism is scarce. This correlational, cross-sectional survey study was conducted to determine the association between seven interventions—behavioral, social, mental health, daily living skills, vocational, mindfulness, and medications—and the QoL and mental health of adults 18 years and older with autism with no intellectual disability living in Canada. A national sample of 182 autistic adults completed the survey that used the WHOQOL-BREF and Depression, Anxiety, and Stress Scale to measure subjective QoL and mental health, respectively. Behavioral, mental health, and medications were the mostly used interventions (67%, 71.4%, and 82.4%). QoL was lower across all domains of the WHOQOL-BREF compared to the general population and moderate levels of anxiety and depression were reported. Hierarchical multiple regression analysis showed that characteristics, such as autism severity, being female, and older age negatively predicted QoL across all domains except for the physical domain, whereas being in a relationship positively predicted social QoL explaining 35.2% of the variance. Of the seven interventions used, behavioral therapies and receiving mental health support consistently predicted a better QoL across all domains, except for the environment domain where only mental health support was a significant predictor. Autism severity negatively predicted anxiety and depression while none of the interventions reached statistical significance. These findings suggest prioritizing provision of behavioral and mental health interventions to adults with autism and inform future research to evaluate their effectiveness in QoL outcomes as an end goal
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