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Related papers: Long-Term Light Curve of Highly-Variable Protostel…

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We present ten years of new photometric monitoring of the light variability of five evolved stars with strong mid-infrared emission from surrounding dust. Three are known carbon-rich proto-planetary nebulae (PPNe) with F$-$G spectral types;…

Solar and Stellar Astrophysics · Physics 2020-01-08 Bruce J. Hrivnak , Gary Henson , Todd C. Hillwig , Wenxian Lu , Brian W. Murphy , Ronald H. Kaitchuck

Discovery of periodic maser emission was an unexpected result from monitoring observations of methanol transitions in high-mass young stellar objects. We report on the detection of five new periodic sources from a monitoring program with…

Solar and Stellar Astrophysics · Physics 2020-01-08 Mateusz Olech , Marian Szymczak , Paweł Wolak , Rafał Sarniak , Anna Bartkiewicz

Magnetic chemically peculiar (mCP) stars are strongly magnetic upper main-sequence stars that exhibit light rotational variability due to an uneven surface distribution of certain peculiar elements, which may appear in phase at certain…

3C 454.3 is frequently observed in flaring state. The long term light curve of this source has been analysed with 9 year (August 2008 - July 2017) data from Fermi LAT detector. We have identified five flares and one quiescent state. The…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Avik Kumar Das , Raj Prince , Nayantara Gupta

Results of the long-term monitoring observations of the 6.7 GHz Class II methanol masers associated with the four high-mass star-forming regions by Hitachi 32-m radio telescope are presented. We detected periodic flux variability in…

Astrophysics of Galaxies · Physics 2024-02-28 Yoshihiro Tanabe , Yoshinori Yonekura

Variability is a defining characteristic of young low-mass stars that are still accreting material from their primordial protoplanetary disk. Here we present the largest \textit{HST} variability study of Classical T Tauri stars (CTTS) to…

Solar and Stellar Astrophysics · Physics 2019-04-10 Connor Robinson , Catherine Espaillat

We present new results on the classical T Tauri star RU Lupi based on three observing runs collecting high-resolution spectra, complementary NIR spectra, multicolour photometric data, and X-ray observations. The photospheric absorption…

Solar and Stellar Astrophysics · Physics 2015-06-17 Gösta F. Gahm , Henricus C. Stempels , Frederick M. Walter , Peter P. Petrov , Gregory J. Herczeg

We present the first spectrum of a highly veiled, strongly accreting protostar which shows photospheric absorption features and demonstrates the stellar nature of its central core. We find the spectrum of the luminous (L_bol = 10 L_sun)…

Astrophysics · Physics 2009-11-07 Thomas P. Greene , Charles J. Lada

Using the Boolardy Engineering Test Array of the Australian Square Kilometre Array Pathfinder (ASKAP BETA), we have carried out the first $z = 0 - 1$ survey for HI and OH absorption towards the gravitationally lensed quasars PKSB1830$-$211…

We carried out a new and sensitive search for long-period variability in the prototype of the Mira class of long-period pulsating variables, o Ceti (Mira A), the closest and brightest Mira variable. We conducted this search using an…

Solar and Stellar Astrophysics · Physics 2011-02-11 Matthew R. Templeton , Margarita Karovska

We have built the historical light curve of the luminous variable GR 290 back to 1901, from old observations of the star found in several archival plates of M 33. These old recordings together with published and new data show that for at…

Three fields located close to the center of the globular cluster Omega Cen were surveyed in a search for variable stars. We present V-band light curves for 32 periodic variables. This sample includes 10 SX Phe stars, 19 eclipsing binaries,…

Astrophysics · Physics 2009-10-28 J. Kaluzny , M. Kubiak , M. Szymanski , A. Udalski , W. Krzeminski , M. Mateo , K. Stanek

The high-frequency peaked BL Lac object 1ES 0229+200 (z = 0.14) was first detected in very high energy (VHE, E > 100 GeV) $\gamma$-rays by the H.E.S.S. (High Energy Stereoscopic System) collaboration in 2006. No flux variability was…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Gabriele Cologna , Mahmoud Mohamed , Stefan J. Wagner , Alicja Wierzcholska , Carlo Romoli , Omar Kurtanidze

We analyse public domain time-series photometric observations of 30 known and candidate binary post-AGB stars for measuring pulsation and orbital periods. We derive periodicities for 17 stars for the first time in the literature. Besides…

Astrophysics · Physics 2008-11-26 L. L. Kiss , A. Derekas , Gy. M. Szabo , T. R. Bedding , L. Szabados

We report the discovery of 6.7 GHz methanol maser periodic flares in four massive star forming regions and the updated light curve for the known periodic source G22.357+0.066. The observations were carried out with the Torun 32 m radio…

Astrophysics of Galaxies · Physics 2015-06-23 M. Szymczak , P. Wolak , A. Bartkiewicz

We summarize Hubble Space Telescope (HST) UV observations of the weak-lined T Tauri star (wTTS) PDS 70 obtained with the Space Telescope Imaging Spectrograph (STIS). These observations provide the first far-UV (FUV) and near-UV (NUV)…

Solar and Stellar Astrophysics · Physics 2022-10-26 Stephen L. Skinner , Marc Audard

We study the optical light curves - primarily probing the variable emission from the accretion disk - of ~ 900 extreme variability quasars (EVQs, with maximum flux variations more than 1 mag) over an observed-frame baseline of ~ 16 years…

Astrophysics of Galaxies · Physics 2020-04-14 Yuanze Luo , Yue Shen , Qian Yang

Light curves of the accreting white dwarf pulsator GW Librae spanning a 7.5 month period in 2017 were obtained as part of the Next Generation Transit Survey. This data set comprises 787 hours of photometry from 148 clear nights, allowing…

We have carried out a detailed observational study of the light, color, and velocity variations of two bright, carbon-rich proto-planetary nebulae, IRAS 22223+4327 and 22272+5435. The light curves are based upon our observations from 1994…

Solar and Stellar Astrophysics · Physics 2015-06-17 Bruce J. Hrivnak , Wenxian Lu , Julius Sperauskas , Hans Van Winckel , David Bohlender , Laimons Zacs