- ID:
- ivo://CDS.VizieR/J/AJ/149/184
- Title:
- Long-term photometry for 4 O-rich PPne
- Short Name:
- J/AJ/149/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new light curves covering 14-19years of observations of four bright proto-planetary nebulae (PPNs), all oxygen-rich and of F spectral type. They each display cyclical light curves with significant variations in amplitude. All four were previously known to vary in light. Our data were combined with published data and searched for periodicity. The results are as follows: IRAS 19475+3119 (HD331319; 41.0days), 17436+5003 (HD161796; 45.2days), 19386+0155 (101.8days), and 18095+2704 (113.3days). The two longer periods are in agreement with previous studies while the two shorter periods each reveal for the first time a dominant period over these long observing intervals. Multiple periods were also found for each object. The secondary periods were all close to the dominant periods, with P_2_/P_1_ ranging from 0.86 to 1.06. The variations in color reveal maximum variations in T_eff_of 400-770K. These variations are due to pulsations in these post-asymptotic giant branch objects. Maximum seasonal light variations are all less than 0.23mag (V), consistent for their temperatures and periods with the results of Hrivnak et al. for 12 C-rich PPNs. For all of these PPNs, there is an inverse relationship between period and temperature; however, there is a suggestion that the period-temperature relationship may be somewhat steeper for the O-rich than for the C-rich PPNs.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/568/A49
- Title:
- Long-term photometry of pre-MS stars
- Short Name:
- J/A+A/568/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To broaden the search and study stars in the early evolutionary phase, we investigated a sample of 17 pre-main sequence objects previously detected as either H{alpha} emission-line pre-main sequence stars or T Tauri variables located in the field of the North America/Pelican Nebula complex. Johnson-Cousins B, V, Rc, Ic magnitudes and mean color indices for the program stars are determined from more than 12400 measurements from archive photographic plates and from CCD data collected at 7 observatories covering the period of almost 60 years from 1954 up to 2013. We complemented previously rare insights on the photometry of the program stars and presented their photometric history, which for almost all program stars is the first long term photometric monitoring on a timescale of 6 decades. Eight program stars are found to be classical T Tauri stars of variability type II, while 6 program stars are weak-line T Tauri stars of variability type I. For the first time, periodicity is found for three stars: V1716 Cyg indicates a 4.15 day period, V2051 Cyg indicates a 384 day period, and V521 Cyg a period of 503 days.
- ID:
- ivo://CDS.VizieR/J/other/JAD/18.5
- Title:
- Long-term photometry of 11 RS CVn stars
- Short Name:
- J/other/JAD/18.5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I present BVRI photometry of short-period (P<1d) eclipsing RS CVn binary star systems collected between 1988 and 2009 at Mount Laguna Observatory. Most of the data are for ER Vul and WY Cnc, with light curves nearly every year during that time period. I also present light curves for at least several years for XY UMa, BH Vir, CG Cyg, RT And, and UV Psc. I have fewer light curves for SV Cam, UV Leo, 1E1919+0427, and GSC 2038-0293. In addition to the eclipsing short-period systems, I also include UBVRI data for two longer period non-eclipsing RS CVn binary systems: UZ Lib and DM UMa, as well as two active chromosphere single stars: FK Com and HD 199178.
- ID:
- ivo://CDS.VizieR/II/170
- Title:
- Long-term photometry of Variables I.
- Short Name:
- II/170
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first catalogue of photometric data in the Stroemgren system obtained during the period October 1982 - September 1986. Full description can be found in ESO report SP 8. Since our goal is not absolute (all-sky) photometry, the observations should be used for differential photometry only. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 5 of paper) ------------------------------------ System y b-y m1 c1 ------------------------------------ 1 0.0109 0.0088 0.0133 0.0136 4 0.0068 0.0057 0.0079 0.0118 5 0.0087 0.0070 0.0114 0.0114 6 0.0090 0.0078 0.0126 0.0132 7 0.0071 0.0033 0.0041 0.0065 ------------------------------------
- ID:
- ivo://CDS.VizieR/II/188
- Title:
- Long-term photometry of Variables II
- Short Name:
- II/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The second catalogue of the LTPV programme contains photometric data obtained during the period October 1986 - September 1990. Full description can be found in ESO reports SP 8 and 12. The data presented here have been upgraded since the printing of catalogue ESO SR 12; a major change is the use of a quite different standard, namely the ESO SAT (Stroemgren Automatic Telescope) instrumental system has been used as standard. The instrumental systems 6 and 8 can be obtained by applying the following color matrices (see ESO SR 12, page 4, Eq. (3)), inverted (b-y , y , m1 , c1): SYSTEM 6 1.0518 0.0000 0.0000 0.0000 0.0094 1.0000 0.0000 0.0000 -0.1238 0.0000 1.1206 0.0000 0.0426 0.0000 0.0000 1.0352 SYSTEM 8 1.0476 0.0000 0.0000 0.0000 0.0384 1.0000 0.0000 0.0000 -0.0877 0.0000 1.0487 0.0000 -0.2657 0.0000 0.0000 0.9732 It also very easy to go back to the same standard as in ESO SR 8 by applying the transformations given in Table 3 of ESO SR 12 (page 3). Note that the faint star C7060 is not identified so far. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 5 of paper) ------------------------------------ System y b-y m1 c1 ------------------------------------ 6 0.0069 0.0058 0.0122 0.0129 7 0.0064 0.0030 0.0039 0.0067 8 0.0068 0.0061 0.0110 0.0097 ------------------------------------
- ID:
- ivo://CDS.VizieR/II/200
- Title:
- Long-term photometry of Variables III
- Short Name:
- II/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the third catalogue of photometric data in the Stroemgren system obtained during the period October 1990-January 1992 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. All data have been obtained with the Danish 50-cm telescope. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 4 of paper) ------------------------------ y b-y m1 c1 ------------------------------ 0.005 0.002 0.004 0.006 ------------------------------
- ID:
- ivo://CDS.VizieR/II/202
- Title:
- Long-term photometry of Variables IV
- Short Name:
- II/202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the fourth catalogue of photometric data in the Stroemgren system obtained during the period June 18, 1992 - August 23, 1994 in the framework of the Long-Term Photometry of Variables (LTPV) program at the European Southern Observatory. Since our goal is not absolute (all-sky) photometry, the observations should be used for differential photometry only. The mean values of the r.m.s. deviations of the differential measurements of comparison stars are around (from Table 3 of paper) ------------------------------ y b-y m1 c1 ------------------------------ 0.005 0.002 0.004 0.007 ------------------------------
- ID:
- ivo://CDS.VizieR/J/AJ/146/78
- Title:
- Long-term Swift monitoring of WPVS 007
- Short Name:
- J/AJ/146/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS1) galaxy WPVS007. The galaxy was monitored with Swift between 2005 October and 2013 July, after it had previously undergone a dramatic drop in its X-ray flux. For the first time, we are able to repeatedly detect this NLS1 in X-rays again. This increased number of detections in the last couple of years may suggest that the strong absorber that has been found in this active galactic nucleus (AGN) is starting to become leaky and may eventually disappear. The X-ray spectra obtained for WPVS007 are all consistent with a partial covering absorber model. A spectrum based on the data during the extreme low X-ray flux states shows that the absorption column density is of the order of 4x10^23^/cm2 with a covering fraction of 95%. WPVS007 also displays one of the strongest UV variabilities seen in NLS1s. The UV continuum variability anti-correlates with the optical/UV slope {alpha}_UV_, which suggests that the variability may be primarily due to reddening. The UV variability timescales are consistent with moving dust "clouds" located beyond the dust sublimation radius of R_sub_{approx}20lt-days. We present for the first time near-infrared JHK data of WPVS007, which reveal a rich emission-line spectrum. Recent optical spectroscopy does not indicate significant variability in the broad permitted and FeII emission lines, implying that the ionizing continuum seen by those gas clouds has not significantly changed over the last decades. All X-ray and UV observations are consistent with a scenario in which an evolving broad absorption line (BAL) flow obscures the continuum emission. As such, WPVS007 is an important target for our understanding of BAL flows in low-mass AGNs.
- ID:
- ivo://CDS.VizieR/J/other/PASA/32.11
- Title:
- Long-term UBVRI photometry of GM Cep
- Short Name:
- J/other/PASA/32.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results from UBVRI photometric observations of the pre-main sequence star GM Cephei obtained in the period April 2011 - August 2014 are reported in the paper. Presented data are a continuation of our photometric monitoring of the star started in 2008. GM Cep is located in the field of the young open cluster Trumpler 37 and over the past years it has been an object of intense photometric and spectral studies. The star shows a strong photometric variability interpreted as a possible outburst from EXor type in previous studies. Our photometric data for a period of over six years show a large amplitude variability ({Delta}V~2.3mag) and several deep minimums in brightness are observed. The analysis of the collected multicolor photometric data show the typical of UX Ori variables a colour reversal during the minimums in brightness. The observed decreases in brightness have a different shape, and evidences of periodicity are not detected. At the same time, high amplitude rapid variations in brightness typical for the classical T Tauri stars also present on the light curve of GM Cep. The spectrum of GM Cep shows the typical of classical T Tauri stars wide H alpha emission line and absorption lines of some metals. We calculate the outer radius of the H{alpha} emitting region as 10.4+/-0.5R_{sun}_ and the accretion rate as 1.8x10^-7^M_{sun}_/yr.
- ID:
- ivo://CDS.VizieR/J/ApJS/241/33
- Title:
- Long-term variability in the radio-quiet AGN Ark120
- Short Name:
- J/ApJS/241/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the long-term variability in the optical monitoring database of Ark 120, a nearby radio-quiet active galactic nucleus (AGN) at a distance of 143Mpc (z=0.03271). We compiled the historical archival photometric and spectroscopic data since 1974 and conducted a new two-year monitoring campaign in 2015-2017, resulting in a total temporal baseline over four decades. The long-term variations in the optical continuum exhibit a wave-like pattern and the H{beta} integrated flux series varies with a similar behavior. The broad H{beta} profiles have asymmetric double peaks, which change strongly with time and tend to merge into a single peak during some epochs. The period in the optical continuum determined from various period-search methods is about 20yr, and the estimated false alarm probability with null hypothesis simulations is about 1x10^-3^. The overall variations of the broad H{beta} profiles also follow the same period. However, the present database only covers two cycles of the suggested period, which strongly encourages continued monitoring to track more cycles and confirm the periodicity. Nevertheless, in light of the possible periodicity and the complicated H{beta} profile, Ark 120 is one candidate of the nearest radio-quiet AGNs with possible periodic variability, and it is thereby a potential candidate host for a sub-parsec supermassive black hole binary.
