scholarly journals Observations of the transiting planet TrES-2 with the AIU Jena telescope in Großschwabhausen

2008 ◽  
Vol 4 (S253) ◽  
pp. 436-439 ◽  
Author(s):  
S. Raetz ◽  
M. Mugrauer ◽  
T. O. B. Schmidt ◽  
T. Roell ◽  
T. Eisenbeiss ◽  
...  
Keyword(s):  
High Precision ◽  
Orbital Period ◽  
Ccd Camera ◽  
Light Curves ◽  
Orbital Parameters ◽  
Transiting Planets ◽  
Photometric Monitoring ◽  
Cassegrain Telescope ◽  
Parent Star ◽  
Planetary Transits

AbstractWe have started high precision photometric monitoring observations at the AIU Jena observatory in Großschwabhausen near Jena in fall 2006. We used a 25.4cm Cassegrain telescope equipped with a CCD-camera mounted piggyback on a 90cm telescope. To test the attainable photometric precision, we observed stars with known transiting planets. We could recover all planetary transits observed by us.We observed the parent star of the transiting planet TrES-2 over a longer period in Großschwabhausen. Between March and November 2007 seven different transits and almost a complete orbital period were analyzed. Overall, in 31 nights of observation 3423 exposures (in total 57.05h of observation) of the TrES-2 parent star were taken. Here, we present our methods and the resulting light curves. Using our observations we could improve the orbital parameters of the system.

scholarly journals What Photometric Space Telescopes Can Tell Us About Extrasolar Giant Planets

2004 ◽  
Vol 202 ◽  
pp. 468-470
Author(s):  
S. Seager ◽  
Lam Hui
Keyword(s):  
Giant Planets ◽  
Light Curves ◽  
Planetary Rings ◽  
Space Telescopes ◽  
Transiting Planets ◽  
Reflected Light ◽  
Parent Star

Within the next few years three microsatellites with part-per-million photometric capability (MOST, MONS, COROT) will be launched. These space telescopes, which were designed for asteroseismology, as well as other proposed or planned space telescopes to detect Earth-like transiting planets (Kepler and Eddington), will be able to observe the reflected light curves of the close-in extrasolar giant planets (CEGPs). The CEGPs are 0.05 AU from their parent star and are potentially bright in reflected light. For a transiting planet (at any orbital distance) moons and planetary rings may be detected.

scholarly journals An extreme amplitude, massive heartbeat system in the LMC characterized using ASAS-SN and TESS

2019 ◽  
Vol 489 (4) ◽  
pp. 4705-4711 ◽  
Author(s):  
T Jayasinghe ◽  
K Z Stanek ◽  
C S Kochanek ◽  
Todd A Thompson ◽  
B J Shappee ◽  
...  
Keyword(s):  
Analytical Model ◽  
Frequency Analysis ◽  
Orbital Period ◽  
Variable Star ◽  
Light Curves ◽  
Type Star ◽  
Orbital Parameters

ABSTRACT Using ASAS-SN data, we find that the bright ($V\sim 13.5$ mag) variable star MACHO 80.7443.1718 (ASASSN-V J052624.38–684705.6) is the most extreme heartbeat star yet discovered. This massive binary, consisting of at least one early B-type star, has an orbital period of $P_{\rm ASAS-SN}=32.83627\pm 0.00846\, {\rm d},$ and is located towards the LH58 OB complex in the LMC. Both the ASAS-SN and TESS light curves show extreme brightness variations of ${\sim }40{{\ \rm per\ cent}}$ at periastron and variations of $ \sim 10{{\ \rm per\ cent}}$ due to tidally excited oscillations outside periastron. We fit an analytical model of the variability caused by the tidal distortions at pericentre to find orbital parameters of $\omega =-61.4^\circ$, $i=44.8^\circ$, and $e=0.566$. We also present a frequency analysis to identify the pulsation frequencies corresponding to the tidally excited oscillations.

scholarly journals TTVs study in southern stars

2011 ◽  
Vol 7 (S286) ◽  
pp. 441-444
Author(s):  
Romina Petrucci ◽  
Emiliano Jofré ◽  
Martín Schwartz ◽  
Andrea Buccino ◽  
Pablo Mauas
Keyword(s):  
Monitoring Program ◽  
San Juan ◽  
Transiting Planets ◽  
Planetary Mass ◽  
Photometric Monitoring ◽  
Host Stars ◽  
Good Agreement ◽  
Planetary Transits

AbstractIn this contribution we present 4 complete planetary transits observed with the 40-cm telescope “Horacio Ghielmetti” located in San Juan(Argentina). These objects correspond to a continuous photometric monitoring program of Southern planet host-stars that we are carrying out since mid-2011. The goal of this project is to detect additional planetary mass objects around stars with known transiting-planets through Transit Timing Variations (TTVs). For all 4 transits the depth and duration are in good agreement with the values published in the discovery papers.

scholarly journals Activity induced variation in spin-orbit angles as derived from Rossiter–McLaughlin measurements

2018 ◽  
Vol 619 ◽  
pp. A150 ◽  
Author(s):  
M. Oshagh ◽  
A. H. M. J. Triaud ◽  
A. Burdanov ◽  
P. Figueira ◽  
A. Reiners ◽  
...  
Keyword(s):  
High Precision ◽  
Active Regions ◽  
Magnetic Activity ◽  
Light Curves ◽  
Spin Orbit ◽  
Stellar Activity ◽  
Transiting Planets ◽  
Exoplanetary Systems ◽  
Active Stars ◽  
Induced Variation

One of the most powerful methods used to estimate sky-projected spin-orbit angles of exoplanetary systems is through a spectroscopic transit observation known as the RossiterMcLaughlin (RM) effect. So far mostly single RM observations have been used to estimate the spin-orbit angle, and thus there have been no studies regarding the variation of estimated spin-orbit angle from transit to transit. Stellar activity can alter the shape of photometric transit light curves and in a similar way they can deform the RM signal. In this paper we present several RM observations, obtained using the HARPS spectrograph, of known transiting planets that all transit extremely active stars, and by analyzing them individually we assess the variation in the estimated spin-orbit angle. Our results reveal that the estimated spin-orbit angle can vary significantly (up to ~42°) from transit to transit, due to variation in the configuration of stellar active regions over different nights. This finding is almost two times larger than the expected variation predicted from simulations. We could not identify any meaningful correlation between the variation of estimated spin-orbit angles and the stellar magnetic activity indicators. We also investigated two possible approaches to mitigate the stellar activity influence on RM observations. The first strategy was based on obtaining several RM observations and folding them to reduce the stellar activity noise. Our results demonstrated that this is a feasible and robust way to overcome this issue. The second approach is based on acquiring simultaneous high-precision short-cadence photometric transit light curves using TRAPPIST/SPECULOOS telescopes, which provide more information about the stellar active region’s properties and allow a better RM modeling.

scholarly journals HATS-34b and HATS-46b: Re-characterisation Using TESS and Gaia

2020 ◽  
Author(s):  
Emma M Louden ◽  
Joel D Hartman
Keyword(s):  
Observational Data ◽  
High Precision ◽  
Light Curves ◽  
Star Mass ◽  
Transiting Planets ◽  
Precision And Accuracy ◽  
Host Stars

Abstract We present a revised characterisation of the previously discovered transiting planet systems HATS-34 and HATS-46. We make use of the newly available space-based light curves from the NASA TESS mission and high-precision parallax and absolute photometry measurements from the ESA Gaia mission to determine the mass and radius of the planets and host stars with dramatically increased precision and accuracy compared to published values, with the uncertainties in some parameters reduced by as much as a factor of seven. Using an isochrone-based fit, for HATS-34 we measure a revised host star mass and radius of $0.952^{+0.040}_{-0.020}\, M_\odot$ and of 0.9381 ± 0.0080 R⊙, respectively, and a revised mass and radius for the transiting planet of 0.951 ± 0.050 MJ, and 1.282 ± 0.064 RJ, respectively. Similarly, for HATS-46 we measure a revised mass and radius for the host star of 0.869 ± 0.023 M⊙, and 0.894 ± 0.010 R⊙, respectively, and a revised mass and radius for the planet of 0.158 ± 0.042 MJ, and 0.951 ± 0.029 RJ, respectively. The uncertainties that we determine on the stellar and planetary masses and radii are also substantially lower than re-determinations that incorporate the Gaia results without performing a full re-analysis of the light curves and other observational data. We argue that, in light of Gaia and TESS, a full re-analysis of previously discovered transiting planets is warranted.

The Eclipsing Binary WX Eridani

1979 ◽  
Vol 46 ◽  
pp. 385
Author(s):  
M.B.K. Sarma ◽  
K.D. Abhankar
Keyword(s):  
Light Curve ◽  
Spectral Type ◽  
Orbital Period ◽  
Primary Component ◽  
Light Curves ◽  
Absorption Feature ◽  
Primary Star ◽  
Eclipsing Binary ◽  
The Times ◽  
Phase Angles

AbstractThe Algol-type eclipsing binary WX Eridani was observed on 21 nights on the 48-inch telescope of the Japal-Rangapur Observatory during 1973-75 in B and V colours. An improved period of P = 0.82327038 days was obtained from the analysis of the times of five primary minima. An absorption feature between phase angles 50-80, 100-130, 230-260 and 280-310 was present in the light curves. The analysis of the light curves indicated the eclipses to be grazing with primary to be transit and secondary, an occultation. Elements derived from the solution of the light curve using Russel-Merrill method are given. From comparison of the fractional radii with Roche lobes, it is concluded that none of the components have filled their respective lobes but the primary star seems to be evolving. The spectral type of the primary component was estimated to be F3 and is found to be pulsating with two periods equal to one-fifth and one-sixth of the orbital period.

scholarly journals MOST Spacebased Photometry of HD 189733: Precise Timing Measurements for Transits Across an Active Star

2008 ◽  
Vol 4 (S253) ◽  
pp. 459-461
Author(s):  
E. Miller-Ricci ◽  
J. F. Rowe ◽  
D. Sasselov ◽  
J. M. Matthews ◽  
R. Kuschnig ◽  
...  
Keyword(s):  
Orbital Period ◽  
Mass Range ◽  
Active Star ◽  
Precise Timing ◽  
Resonant Orbits ◽  
The Earth ◽  
Test Spot ◽  
Transit Times ◽  
Nearly Continuous ◽  
Parent Star

AbstractWe have measured transit times for HD 189733 passing in front of its bright (V = 7.67) chromospherically active and spotted parent star. Nearly continuous broadband photometry of this system was obtained with the MOST (Microvariability & Oscillations of STars) space telesope during 21 days in August 2006, monitoring 10 consecutive transits. We have used these data to search for deviations from a constant orbital period which can indicate the presence of additional planets in the system that are as yet undetected by Doppler searches. We find no variations above the level of ±45 s, ruling out planets in the Earth-to-Neptune mass range in a number of resonant orbits. We find that a number of complications can arise in measuring transit times for a planet transiting an active star with large star spots. However, such transiting systems are also useful in that they can help to constrain and test spot models. This has implications for the large number of transiting systems expected to be discovered by the CoRoT and Kepler missions.

scholarly journals A multi-wavelength analysis of the WASP-12 planetary system

2010 ◽  
Vol 6 (S276) ◽  
pp. 163-166 ◽  
Author(s):  
Luca Fossati ◽  
Carole A. Haswell ◽  
Cynthia S. Froning
Keyword(s):  
Magnetic Field ◽  
Atmospheric Pollution ◽  
Planetary System ◽  
Light Curves ◽  
Absorption Lines ◽  
Transiting Planets ◽  
Multi Wavelength ◽  
Global Magnetic Field ◽  
Solar Type ◽  
Solar Type Star

AbstractWASP-12 is a 2 Gyr old solar type star, hosting WASP-12b, one of the most irradiated transiting planets currently known. We observed WASP-12 in the UV with the Cosmic Origins Spectrograph (COS) on HST. The light curves we obtained in the three covered UV wavelength ranges, all of which contain many photospheric absorption lines, imply effective radii of 2.69±0.24 RJ, 2.18±0.18 RJ, and 2.66±0.22 RJ, suggesting that the planet is surrounded by an absorbing cloud which overfills the Roche lobe. We clearly detected enhanced transit depths at the wavelengths of the MgII h&k resonance lines. Spectropolarimetric analysis of the host star was also performed. We found no global magnetic field, but there were hints of atmospheric pollution, which might be connected to the very unusual activity of the host star.

scholarly journals Long-term Photometric Monitoring of FUor and FUor-like Objects

2018 ◽  
pp. 240-248
Author(s):  
E. Semkov ◽  
S. Ibryamov ◽  
S. Peneva ◽  
A. Mutafov
Keyword(s):  
Light Curve ◽  
Significant Role ◽  
Stellar Evolution ◽  
Photographic Plate ◽  
Light Curves ◽  
Curve Shape ◽  
Rate Of Increase ◽  
Fu Ori ◽  
Photometric Monitoring

A phenomenon with a significant role in stellar evolution is the FU Orionis (FUor) type of outburst. The first three (classical) FUors (FU Ori, V1515 Cyg and V1057 Cyg) are well-studied and their light curves are published in the literature. But recently, over a dozen new objects of this type were discovered, whose photometric history we do not know well. Using recent data from photometric monitoring and data from the photographic plate archives we aim to study, the long-term photometric behavior of FUor and FUor-like objects. The construction of the historical light curves of FUors could be very important for determining the beginning of the outburst, the time to reach the maximum light, the rate of increase and decrease in brightness, the pre-outburst variability of the star. So far we have published our results for the light curves of V2493 Cyg, V582 Aur, Parsamian 21 and V1647 Ori. In this paper we present new data that describe more accurate the photometric behavior of these objects. In comparing our results with light curves of the well-studied FUors (FU Ori, V1515 Cyg and V1057 Cyg), we conclude that every object shows different photometric behavior. Each known FUor has a different rate of increase and decrease in brightness and a different light curve shape.

scholarly journals CVs Around the Minimum Orbital Period

2015 ◽  
Vol 2 (1) ◽  
pp. 41-45
Author(s):  
S. Zharikov ◽  
G. Tovmassian
Keyword(s):  
Accretion Disk ◽  
Accretion Disks ◽  
Orbital Period ◽  
Cataclysmic Variables ◽  
Outer Edge ◽  
Light Curves ◽  
Mass Ratio ◽  
Period Limit ◽  
Bounce Back ◽  
The Continuum

We discussed features of Cataclysmic Variables at the period minimum. In general, most of them must be WZ Sge-type objects. Main characteristics of the prototype star (WZ Sge) are discussed. A part of WZ Sge-type objects has evolved past the period limit and formed the bounce back systems. We also explore conditions and structure of accretion disks in such systems. We show that the accretion disk in a system with extreme mass ratio grows in size reaching a 2:1 resonance radius and are relatively cool. They also become largely optically thin in the continuum, contributing to the total flux less than the stellar components of the system. In contrast, the viscosity and the temperature in spiral arms formed at the outer edge of the disk are higher and their contribution in continuum plays an increasingly important role. We model such disks and generate light curves which successfully simulate the observed double-humped light curves in the quiescence.

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