Table 3 presents the emission line spectrum of V380 Ori in the optical region observed at OHP in January 1995 with a mean resolution of 10000. For the line blends the wavelength and flux (not reddening corrected) of each contributor are given. For the P-Cygni profiles the equivalent widths of the absorption component are also reported. We estimate an error of less than 10% for the strongest lines, 10% to 40% for the weakest lines.
We present a detailed study of McNeil's nebula (V1647 Ori) in its ongoing outburst phase starting from 2008 September to 2013 March. Our 124 nights of photometric observations were carried out in optical V, R, I, and near-infrared J, H, K bands, and 59 nights of medium-resolution spectroscopic observations were done in the 5200-9000{AA} wavelength range. All observations were carried out with the 2m Himalayan Chandra Telescope and 2m IUCAA Girawali Telescope. Our observations show that over the past four and a half years, V1647 Ori and region C near the Herbig-Haro object HH 22A have been undergoing a slow dimming at a rate of ~0.04mag/yr and ~0.05mag/yr, respectively, in R band, which is six times slower than the rate during a similar stage of V1647 Ori in the 2003 outburst. We detected change in flux distribution over the reflection nebula, implying changes in circumstellar matter distribution between the 2003 and 2008 outbursts. Apart from steady wind of velocity ~350km/s, we detected two episodic magnetic reconnection driven winds. Forbidden [OI]{lambda}6300 and [FeII]{lambda}7155 lines were also detected, implying shock regions probably from jets. We tried to explain the outburst timescales of V1647 Ori using the standard models of the FUors kind of outburst and found that pure thermal instability models like Bell and Lin cannot explain the variations in timescales. In the framework of various instability models we conclude that one possible reason for the sudden ending of the 2003 outburst in 2005 November was a low-density region or gap in the inner region (~1AU) of the disk.
The accretion history of low-mass young stars is not smooth but shows spikes of accretion that can last from months and years to decades and centuries. Observations of young stars in outbursts can help us understand the temporal evolution of accreting stars and the interplay between the accretion disk and the stellar magnetosphere. The young late-type star V1118 Orionis was in outburst from 2005 to 2006. We followed the outburst with optical and near-infrared photometry. The X-ray emission was further probed with observations taken with XMM-Newton and Chandra during and after the outburst. In addition, we obtained mid-infrared photometry and spectroscopy with Spitzer at the peak of the outburst and in the post-outburst phase. The spectral energy distribution of V1118 Ori varied significantly over the course of the outburst. The optical flux showed the largest variations, most likely caused by enhanced emission by a hot spot. The hot spot dominated the optical and near-infrared emission at the peak of the outburst, while the disk emission dominated in the mid-infrared. The emission silicate feature in V1118 Ori is flat and does not vary in shape, but was slightly brighter at the peak of the outburst compared to the post-outburst spectrum. The X-ray flux correlated with the optical and infrared fluxes, indicating that accretion affected the magnetically active corona and the stellar magnetosphere. The thermal structure of the corona was variable with some indication of a cooling of the coronal temperature in the early phase of the outburst with a gradual return to normal values. Color-color diagrams in the optical and infrared showed variations during the outburst, with no obvious signature of reddening caused by circumstellar matter. Using Monte-Carlo realizations of star+disk+hotspot models to fit the spectral energy distributions in "quiescence" and at the peak of the outburst, we determined that the mass accretion rate varied from about 2.5x10^-7^M_{sun}_/yr to 1.0x10^-6^M_{sun}_/yr; in addition, the fractional area of the hotspot increased significantly. The multi-wavelength study of the V1118 Ori outburst helped us to understand the variations in spectral energy distributions and demonstrated the interplay between the disk and the stellar magnetosphere in a young, strongly accreting star.
We report on a detailed spectroscopic and photometric study of V1046 Orionis undertaken to resolve uncertainties about the period(s) and causes of the spectroscopic and photometric variations of this helium-strong star. We have detected the lines of the secondary star in an extensive series of photographic and electronic spectra. This eliminates any doubt about the duplicity of this star. The orbital elements we derive from our measures of these spectra confirm the unusually large orbital eccentricity, e=0.433, for the short, P=18.65612d, orbital period. The line profiles, V/R ratio of the double H{alpha} emission, residuals of the primary radial velocities from the orbital velocity curve, brightness and colour of the object, magnetic field, and radio emission of this system all vary with a period of 0.9011836d. We tentatively follow earlier investigators in interpreting this as the rotational period of the primary and summarize the evidence of the phase shifts among the different phenomena, using the accurate value of the 0.9d period, to put tight constraints on any future model of these changes. We postpone our own attempt at a quantitative modelling of the variations with the 0.9d period for a separate study.
V1162 Ori is a delta Scuti star with variable period and amplitude. To analyse data acquired in the years 1998-2000, the data were subdivided in smaller subsets to take the amplitude and period variability into account. Four different ways of subdividing the data discussed in the paper are outlined in this table 2. A database containing the observations of V1162 Ori is in preparation; it will be published in the Journal of Astronomical data (http://www.vub.ac.be/STER/JAD/jad.htm).
Voyager 2 Magnetometer Jupiter Resampled Heliographic (RTN) Coords
1.92 Second Data Collection
Short Name:
vg2_mag_jupiter_
Date:
25 Apr 2025 02:04:00
Publisher:
Planetary Data System
Description:
This collection contains Voyager 2 Jupiter encounter magnetometer
data given in Heliographic coordinates and averaged from the 60 ms
instrument sample rate to a 1.92 second resampled rate. All magnetic
field observations are measured in nanoTesla. All of the magnetic
field data are calibrated.
Voyager 1 Magnetometer Jupiter Resampled Heliographic (RTN) Coords
9.60 Second Data Collection
Short Name:
vg1_mag_jupiter_
Date:
25 Apr 2025 01:59:52
Publisher:
Planetary Data System
Description:
This collection contains calibrated magnetic field data acquired by
the Voyager 1 Low Field Magnetometer (LFM) during the Jupiter
encounter. Coverage begins in the solar wind inbound to Jupiter and
continues past the last outbound bowshock crossing. The data are in
Heliographic (RTN) coordinates and have been averaged from the 1.92
second summary data to a 9.6 second sample rate. All magnetic field
measurements are given in nanoTesla (nT).
Voyager 2 Magnetometer Jupiter Resampled Heliographic (RTN) Coords
48.0 Second Data Collection
Short Name:
vg2_mag_jupiter_
Date:
25 Apr 2025 02:00:47
Publisher:
Planetary Data System
Description:
This collection contains Voyager 2 Jupiter encounter magnetometer
data given in Heliographic coordinates and averaged from the 60 ms
instrument sample rate to a 48 second resampled rate. All magnetic
field observations are measured in nanoTesla. All of the magnetic
field data are calibrated.
Voyager 2 Magnetometer Jupiter Resampled Heliographic (RTN) Coords
9.60 Second Data Collection
Short Name:
vg2_mag_jupiter_
Date:
25 Apr 2025 02:08:00
Publisher:
Planetary Data System
Description:
This collection contains Voyager 2 Jupiter encounter magnetometer
data given in Heliographic coordinates and averaged from the 60 ms
instrument sample rate to a 9.6 second resampled rate. All magnetic
field observations are measured in nanoTesla. All of the magnetic
field data are calibrated.
Voyager 1 Magnetometer Jupiter Resampled Heliographic (RTN) Coords
48.0 Second Data Collection
Short Name:
vg1_mag_jupiter_
Date:
25 Apr 2025 02:05:01
Publisher:
Planetary Data System
Description:
This collection contains calibrated magnetic field data acquired by
the Voyager 1 Low Field Magnetometer (LFM) during the Jupiter
encounter. Coverage begins in the solar wind inbound to Jupiter and
continues past the last outbound bowshock crossing. The data are in
Heliographic (RTN) coordinates and have been averaged from the 9.6
second summary data to a 48 second sample rate. All magnetic field
measurements are given in nanoTesla (nT).
