Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userRadial Velocity Follow-up of Planetary Transit Candidate MACHO.120.22303.5389
99
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We present preliminary results on the radial velocity follow-up of a planetary transit candidate (P=2.43d, V=15.4) detected during the MACHO project. The photometry is consistent with a grazing transit of an object with radius >=1.8RJ orbiting a K dwarf star, and is the brightest best candidate detected from MACHO. Results from the 2.2m MPG/ESO telescope and FEROS (R=48,000) in May 2006 display an apparent radial velocity variation with amplitude ~650m/s with the same period as the transit, and a solar-type primary. This is consistent with an orbiting companion of mass ~4MJ. However, further observations display an additional secondary long-period variation with amplitude of several km/s, indicating the presence of a third body. The system is likely a low mass eclipsing binary orbiting the solar-type primary. Further observations are planned to fully characterize the system.
rate research
Read More
We present an extension of the formalism recently proposed by Pepper & Gaudi to evaluate the yield of transit surveys in homogeneous stellar systems, incorporating the impact of correlated noise on transit time-scales on the detectability of transits, and simultaneously incorporating the magnitude limits imposed by the need for radial velocity follow-up of transit candidates. New expressions are derived for the different contributions to the noise budget on transit time-scales and the least-squares detection statistic for box-shaped transits, and their behaviour as a function of stellar mass is re-examined. Correlated noise that is constant with apparent stellar magnitude implies a steep decrease in detection probability at the high mass end which, when considered jointly with the radial velocity requirements, can severely limit the potential of otherwise promising surveys in star clusters. However, we find that small-aperture, wide field surveys may detect hot Neptunes whose radial velocity signal can be measured with present-day instrumentation in very nearby (<100 pc) clusters.
Radial Velocity follow-up is essential to establish or exclude the planetary nature of a transiting companion as well as to accurately determine its mass. Here we present some elements of an efficient Doppler follow-up strategy, based on high-resolution spectroscopy, devoted to the characterization of transiting candidates. Some aspects and results of the radial velocity follow-up of the CoRoT space mission are presented in order to illustrate the strategy used to deal with the zoo of transiting candidates.
The space missions TESS and PLATO plan to double the number of 4000 exoplanets already discovered and will measure the size of thousands of exoplanets around the brightest stars in the sky, allowing ground-based radial velocity spectroscopy follow-up to determine the orbit and mass of the detected planets. The new facility we are developing, MARVEL (Raskin et al. this conference), will enable the ground-based follow-up of large numbers of exoplanet detections, expected from TESS and PLATO, which cannot be carried out only by the current facilities that achieve the necessary radial velocity accuracy of 1 m/s or less. This paper presents the MARVEL observation strategy and performance analysis based on predicted PLATO transit detection yield simulations. The resulting observation scenario baseline will help in the instrument design choices and demonstrate the effectiveness of MARVEL as a TESS and PLATO science enabling facility.
We present precision 4.5 $mu$m Spitzer transit photometry of eight planet candidates discovered by the K2 mission: K2-52 b, K2-53 b, EPIC 205084841.01, K2-289 b, K2-174 b, K2-87 b, K2-90 b, and K2-124 b. The sample includes four sub-Neptunes and two sub-Saturns, with radii between 2.6 and 18 $R_oplus$, and equilibrium temperatures between 440 and 2000 K. In this paper we identify several targets of potential interest for future characterization studies, demonstrate the utility of transit follow-up observations for planet validation and ephemeris refinement, and present new imaging and spectroscopy data. Our simultaneous analysis of the K2 and Spitzer light curves yields improved estimates of the planet radii, and multi-wavelength information which help validate their planetary nature, including the previously un-validated candidate EPIC 205686202.01 (K2-289 b). Our Spitzer observations yield an order of magnitude increase in ephemeris precision, thus paving the way for efficient future study of these interesting systems by reducing the typical transit timing uncertainty in mid-2021 from several hours to a dozen or so minutes. K2-53 b, K2-289 b, K2-174 b, K2-87 b, and K2-90 b are promising radial velocity (RV) targets given the performance of spectrographs available today or in development, and the M3V star K2-124 hosts a temperate sub-Neptune that is potentially a good target for both RV and atmospheric characterization studies.
We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors and their candidate sky locations were observed by the Swift observatory. Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a blind injection challenge. With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
