Review of Planetary Systems Around Three Stars

This article focuses on the review of three planetary systems located around the stars HD 99492, HD 147379, and HD 190007. In this work, we aimed to update our knowledge of these systems using data collected by the HARPS-N telescope. The review highlights the discoveries made and the significance of the data obtained through extensive observations.

#Observations and Data Collection

The HARPS-N telescope is located in the Northern hemisphere and is used for observing various stars to detect planetary systems. Between January 2014 and June 2022, we collected data from HD 99492, while HD 147379 was observed from February 2013 to August 2020. HD 190007 was monitored between July 2015 and May 2019. Our observations involved multiple measurements to ensure the accuracy of the data.

The observations yielded Radial Velocity (RV) measurements which are crucial for detecting the presence of planets. Alongside the RV data, we gathered other indicators to analyze the activity of the stars, including the S-index and the full width at half maximum (FWHM) of cross-correlation functions.

#Analysis of HD 99492

#Properties of HD 99492

HD 99492 is a K-type star in a binary system with another star named HD 99491. The two stars are separated by a distance of about 513.9 astronomical units. We detected a new planet, HD 99492 c, which has an Orbital Period of 95.2 days and a minimum mass of 17.9 Earth masses. HD 99492 b also has updated parameters.

#Stellar Activity and Data Processing

To refine our results, we applied advanced data analysis tools to account for any noise or fluctuations in the measurements. We employed a systematic approach to model the data and identify potential planetary signals while accounting for the noise introduced by stellar activity.

#Planetary Detection

The analysis revealed a clear signal associated with HD 99492 c. The measurements indicated a strong correlation between the S-index and radial velocity, further supporting the planetary hypothesis. The observational techniques employed helped to distinguish between stellar noise and actual planetary signals.

#Analysis of HD 147379

#Properties of HD 147379

HD 147379 is an M-type star known to host a planet, HD 147379 b, with a confirmed orbital period of 86.5 days. The planet is located in the habitable zone of its star, making this system particularly interesting for further study.

#Stellar Activity

Similar to HD 99492, we needed to account for the stellar activity of HD 147379. Our analysis showed a correlation between the star's activity indicators and the radial velocity measurements. This correlation suggested that the measurements taken were influenced by the star's rotation and magnetic activity.

#Planetary Search

Using our refined data from HARPS-N, we conducted a search for additional planets in the HD 147379 system. The analysis confirmed the presence of HD 147379 b but did not reveal any additional planetary candidates. The refined parameters showed that HD 147379 b has a minimum mass of around 21.6 Earth masses.

#Analysis of HD 190007

#Properties of HD 190007

HD 190007 is a K-type star observed for its potential planetary companion. Previous studies suggested a candidate planet, which we aimed to confirm with our observations.

#Stellar Rotation and Activity

As with the other stars, we observed the stellar activity of HD 190007, which showed periodic variations in the measurements collected. The results suggested a correlation with the star's rotation period.

#Planetary Confirmation

Our analysis supported the presence of a planet around HD 190007, which has an orbital period of 11.7 days and a minimum mass of 15.5 Earth masses. The refined data improved the understanding of the planet's characteristics, and we found no significant evidence of additional planetary companions in this system.

#Data Analysis Techniques

#Overview of Methods

The data analysis involved advanced techniques designed to mitigate noise from stellar activity and instrument systematics. We used a combination of statistical models to extract meaningful signals from the collected data while correcting for any unwanted influences.

#YARARA and SPLEAF Models

The YARARA model was employed to clean the spectra obtained from HARPS-N by correcting for instrumental effects. This step provided a clearer view of the data, enabling better detection of planetary signals.

The SPLEAF model was used to address the correlated noise caused by stellar activity. By simultaneously analyzing the RV measurements and activity indicators, we enhanced the accuracy of our planetary models.

#Monte Carlo Markov Chain Method

To explore the parameter space of our models, we utilized a Monte Carlo Markov Chain algorithm. This approach allowed us to estimate the posterior distributions of the planet parameters and assess the significance of the detected signals.

#Transit Searches

#Photometric Data Analysis

In addition to the radial velocity measurements, we analyzed the photometric data obtained from the Transiting Exoplanet Survey Satellite (TESS). This search aimed to identify potential transits that would indicate the presence of planets crossing the face of their stars.

#Results of Transit Searches

Despite extensive analysis of the TESS data, we did not find any convincing transit signals for the planets in these systems. The depth and timing of expected transits were not evident in the light curves analyzed.

#Discussion of Findings

#Planetary Systems Established

Our analysis reinforces the presence of two known planetary systems around HD 99492 and HD 147379, along with the confirmation of a planet around HD 190007. The improved parameters for each planet help broaden our understanding of their characteristics and positions in relation to their host stars.

#Importance of Long-Term Observations

This work emphasizes the value of long-term observation campaigns, as the data collected over several years allowed for a more accurate characterization of the stars and their planets. The use of advanced techniques to analyze the data demonstrated the benefits of meticulous data handling in astrophysics.

#Conclusion

The study of planetary systems around HD 99492, HD 147379, and HD 190007 has provided new insights into the dynamics of these intriguing systems. Despite the challenges posed by stellar activity, our advanced observational methods have yielded significant results, including the confirmation of new planets and the refinement of known parameters. Future studies will continue to build on these findings, furthering our exploration of exoplanets and their characteristics within the vast universe.