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 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.

The PLATO mission: Overview and status

2021 ◽  
Author(s):  
Heike Rauer ◽  
Isabella Pagano ◽  
Miguel Mas-Hesse ◽  
Conny Aerts ◽  
Magali Deleuil ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Wide Field ◽  
Operational Conditions ◽  
Ground Segment ◽  
Wide Field Of View ◽  
The Status ◽  
Photometric Monitoring ◽  
Host Stars ◽  
Flight Model ◽  
Made In

<p>PLATO is an ESA mission dedicated to the study of exoplanets and stars, with a planned launch date in 2026. By performing photometric monitoring of about 250 000 bright stars (m<sub>V</sub> < 13), PLATO will be able to discover and characterise hundreds of exoplanets, including small planets orbiting up to the habitable zone of solar-like stars. PLATO’s precision will also allow for a precise characterisation of the host stars through asteroseismology. These objectives require both a wide field of view and high sensitivity, which are achieved with a payload comprising 24 cameras with partially overlapping fields of view. They are complemented by 2 more cameras optimised for brighter stars that will also be used as fine guidance sensor. The PLATO development phase started after the mission adoption in July 2017. The Mission Preliminary Design Review (PDR) was declared successful in October 2020. The implementation and delivery to ESA of the flight model CCDs for all cameras (4 CCDs per camera) has been completed. Currently the Structural Thermal Model (STM) of the payload optical bench is being manufactured, while the STM of a single camera has already been successfully tested. In parallel, a first engineering model of a complete, fully functional camera is being integrated, to verify its performance under operational conditions, and the qualification models of the different payload units are being built.</p> <p>We will present the status of the PLATO payload implementation in the context of the satellite development. In particular, we will describe the payload manufacturing, integration, and tests that will be reviewed at the Critical Milestone in the second half of 2021. We will also summarise the progress made in the science preparation activities, as well as on the ground segment.</p>

scholarly journals A homogeneous spectroscopic analysis of host stars of transiting planets

2009 ◽  
Vol 507 (1) ◽  
pp. 523-530 ◽  
Author(s):  
M. Ammler-von Eiff ◽  
N. C. Santos ◽  
S. G. Sousa ◽  
J. Fernandes ◽  
T. Guillot ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Transiting Planets ◽  
Host Stars

scholarly journals A Rotational Period Study of a Large Sample of Pre-Main Sequence stars in NGC 2264

2004 ◽  
Vol 215 ◽  
pp. 125-126 ◽  
Author(s):  
M. Lamm ◽  
C.A.L. Bailer-Jones ◽  
R. Mundt ◽  
W. Herbst
Keyword(s):  
Main Sequence ◽  
Open Cluster ◽  
Monitoring Program ◽  
Bimodal Distribution ◽  
Main Sequence Stars ◽  
Lower Mass ◽  
Rotation Periods ◽  
Photometric Monitoring ◽  
Pms Stars ◽  
Mass Dependent

We present the results of a photometric monitoring program of pre-main sequence (PMS) stars in the young (2-4 Myr) open cluster NGC 2264 (d=700 pc). We find that the rotation periods are mass dependent and show a bimodal distribution for higher mass stars with M ≳ 0.3 M⊙ and a unimodal distribution for lower mass stars with M ≲ 0.3 M⊙.

scholarly journals Evidence for the Roche Lobe Overflow in VV Cephei

1986 ◽  
Vol 7 ◽  
pp. 211-213 ◽  
Author(s):  
E. F. Guinan ◽  
G. P. McCook ◽  
R. H. Koch ◽  
R. J. Pfeiffer
Keyword(s):  
Binary System ◽  
Red Light ◽  
Monitoring Program ◽  
Close Binary System ◽  
Roche Lobe ◽  
Close Binary ◽  
Intrinsic Variability ◽  
Large Level ◽  
Photometric Monitoring

AbstractThe VV Cep close binary system (O8V + M2 lab; P = 20 3 yrs.) is described from published spectral, radial velocity, photometric, and astrometric results. A long-term photometric monitoring program shows intrinsic variability in a red bandpass. Variability exists on several time scales and the longest of these is attributed to tidal distortion of the cool supergiant by the equally massive hot companion. A theoretical “distortion” light curve, when faced against the observations, indicated the radius of the supergiant to be significantly smaller than the accepted value of ~1600R⊙. This conclusion is examined in the context of a pulse of polarized red light occurring near the time of periastron and interpreted as Roche Lobe overflow of the supergiant envelope. It is shown that the photometric and polarimetrie results may be made accordant, not by appeal to a very large level of scattered red light, but rather by invoking the loss of constraint originally imposed by the Roche Lobe geometry.

Influence of Planets on the Magnetic Activity of Sun-Like Stars

2018 ◽  
Vol 13 (S340) ◽  
pp. 242-243
Author(s):  
Shashanka R. Gurumath ◽  
K. M. Hiremath ◽  
V. Ramasubramanian
Keyword(s):  
Physical Properties ◽  
Power Law ◽  
Magnetic Activity ◽  
The Sun ◽  
Stellar Activity ◽  
Index Data ◽  
Planetary Mass ◽  
Power Law Decay ◽  
Host Stars

AbstractBy considering the physical properties of Sun-like G stars and their exoplanets, present study examines whether presence of planets near the host stars enhances their stellar activity. In order to attain this goal, chromospheric RHK index data-a proxy for the magnetic activity-for the stars with and without planets is considered. With the reasonable constraints on the exoplanetary data, we obtained a power law decay relationship between the magnetic activity of host stars and their ages, for stars with and without planets. Both these results strongly suggest that there is no difference in magnetic activity of the sun-like stars with and without presence of planets. In order to confirm this result, further we also examine an association between the host stars RHK index that have exoplanets and their respective exoplanetary masses. We find that magnitude of RHK (hence magnetic activity) of the host stars is independent of presence of planetary mass in its vicinity.

scholarly journals The PLATO space mission: studying planetary transits and stellar oscillations simultaneously

2008 ◽  
Vol 4 (S253) ◽  
pp. 564-566
Author(s):  
Malcolm Fridlund
Keyword(s):  
Thermal Environment ◽  
Space Mission ◽  
High Time Resolution ◽  
Stellar Oscillations ◽  
Cosmic Vision ◽  
Exoplanetary Systems ◽  
Seismic Oscillations ◽  
Host Stars ◽  
Very High ◽  
Planetary Transits

AbstractPLATO (PLAnetary Transits and Oscilliations of stars) is a proposed mission of the European Space Agency's Science programme Cosmic Vision 2015–2025, currently under industrial study, and with a planned launch by the end of 2017. Its task is to better understand the properties of exoplanetary systems. As such it will detect and characterise exoplanets using their transit signature in front of a large sample of bright stars and simultaneously measuring the seismic oscillations of the parent star of these exoplanets. The mission will be orbiting the Sun-Earth L2 point, which provides a stable thermal environment and maximum uninterrupted observing efficiency. The payload consists of a number (> 28) of individual catadioptric telescopes, covering > 550 sq. degrees. Since the goal is to search for terrestrial exoplanets within the habitable zone of their host stars, and carry out asteroseismological observations of the host stars, very high photometric precision, high time resolution, and high duty-cycle visible photometry is required. Ground-based observations are needed to complement the observations made by PLATO to allow for further exoplanetary characterization. This paper consists of a summary of the preliminary results achieved by the ESA internal pre-assessment study.

scholarly journals Statistical patterns in ground-based transit surveys

2010 ◽  
Vol 6 (S276) ◽  
pp. 129-134
Author(s):  
Andrew Collier Cameron
Keyword(s):  
Environmental Factors ◽  
Mass Range ◽  
Selection Effects ◽  
Dramatic Effect ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
Planetary Mass ◽  
Catastrophic Loss ◽  
Orbital Periods ◽  
Survey Strategy

AbstractAs the number of known transiting planets from ground-based surveys passes the 100 mark, it is becoming possible to perform meaningful statistical analyses on their physical properties. Caution is needed in their interpretation, because subtle differences in survey strategy can lead to surprising selection effects affecting the distributions of planetary orbital periods and radii, and of host-star metallicity. Despite these difficulties, the planetary mass-radius relation appears to conform more or less to theoretical expectations in the mass range from Saturns to super-Jupiters. The inflated radii of many hot Jupiters indicate that environmental factors can have a dramatic effect on planetary structure, and may even lead to catastrophic loss of the planetary envelope under extreme irradiation. High-precision radial velocities and secondary-eclipse timing are yielding eccentricity measurements of exquisite precision. They show some hot Jupiters to be in almost perfectly circular orbits, while others remain slightly but significantly eccentric.

scholarly journals A planetary system with two transiting mini-Neptunes near the radius valley transition around the bright M dwarf TOI-776

2021 ◽  
Vol 645 ◽  
pp. A41
Author(s):  
R. Luque ◽  
L. M. Serrano ◽  
K. Molaverdikhani ◽  
M. C. Nixon ◽  
J. H. Livingston ◽  
...  
Keyword(s):  
Outer Planet ◽  
Low Mass Stars ◽  
Formation Pathway ◽  
Transiting Planets ◽  
Additional Signal ◽  
Wide Range ◽  
Mass Fractions ◽  
Thermally Driven ◽  
Low Mass ◽  
Photometric Monitoring

We report the discovery and characterization of two transiting planets around the bright M1 V star LP 961-53 (TOI-776, J = 8.5 mag, M = 0.54 ± 0.03 M ⊙) detected during Sector 10 observations of the Transiting Exoplanet Survey Satellite (TESS). Combining the TESS photometry with HARPS radial velocities, as well as ground-based follow-up transit observations from the MEarth and LCOGT telescopes, for the inner planet, TOI-776 b, we measured a period of P b = 8.25 d, a radius of R b = 1.85 ± 0.13 R ⊕, and a mass of M b = 4.0 ± 0.9 M ⊕; and for the outer planet, TOI-776 c, a period of P c = 15.66 d, a radius of R c = 2.02 ± 0.14 R ⊕, and a mass of M c = 5.3 ± 1.8 M ⊕. The Doppler data shows one additional signal, with a period of ~34 d, associated with the rotational period of the star. The analysis of fifteen years of ground-based photometric monitoring data and the inspection of different spectral line indicators confirm this assumption. The bulk densities of TOI-776 b and c allow for a wide range of possible interior and atmospheric compositions. However, both planets have retained a significant atmosphere, with slightly different envelope mass fractions. Thanks to their location near the radius gap for M dwarfs, we can start to explore the mechanism(s) responsible for the radius valley emergence around low-mass stars as compared to solar-like stars. While a larger sample of well-characterized planets in this parameter space is still needed to draw firm conclusions, we tentatively estimate that the stellar mass below which thermally-driven mass loss is no longer the main formation pathway for sculpting the radius valley is between 0.63 and 0.54 M ⊙. Due to the brightness of the star, the TOI-776 system is also an excellent target for the James Webb Space Telescope, providing a remarkable laboratory in which to break the degeneracy in planetary interior models and to test formation and evolution theories of small planets around low-mass stars.

scholarly journals TEM identification of Pseudo-nitzschia species from Lisbon Bay (NE Atlantic)

2009 ◽  
Vol 15 (S3) ◽  
pp. 9-10
Author(s):  
A. Amorim ◽  
V. Veloso ◽  
B. Frazão ◽  
A. P. Alves de Matos
Keyword(s):  
Monitoring Program ◽  
Biological Species ◽  
Marine Diatom ◽  
Biological Species Concept ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Amnesic Syndrome ◽  
Diatom Genus ◽  
Identification Of Species ◽  
Good Agreement

AbstractSeveral species of the chain-forming marine diatom genus Pseudo-nitzschia produce domoic acid (DA), a neuroexcitant amino acid, responsible for a human amnesic syndrome after consumption of toxified shellfish (ASP). Since 1995, the Portuguese monitoring program has regularly detected the presence of DA in shellfish. So far only P. australis has been implicated, and references therein. Identification of the causative species of Pseudo-nitzchia in natural samples is hampered by difficulties in identification at the light microscope level. Recent studies have shown that ultrastructural details of the wall, observed by transmission electron microscopy, allow the identification of species in good agreement with the phylogenetic and biological species concept.

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