TESS Reveals HD 118203 b to be a Transiting Planet

• Published in: The Astronomical journal Vol. 159; no. 6; pp. 243 - 254
• Main Authors: Pepper, Joshua, Kane, Stephen R., Rodriguez, Joseph E., Hinkel, Natalie R., Eastman, Jason D., Daylan, Tansu, Mocnik, Teo, Dalba, Paul A., Gaudi, B. Scott, Fetherolf, Tara, Stassun, Keivan G., Campante, Tiago L., Vanderburg, Andrew, Huber, Daniel, Bossini, Diego, Crossfield, Ian, Howell, Steve B., Stephens, Andrew W., Furlan, E., Ricker, George R., Vanderspek, Roland, Latham, David W., Seager, S., Winn, Joshua N., Jenkins, Jon M., Twicken, Joseph D., Rose, Mark, Smith, Jeffrey C., Glidden, Ana, Levine, Alan M., Rinehart, Stephen, Collins, Karen A., Mann, Andrew W., Burt, Jennifer A., James, David J., Siverd, Robert J., Günther, Maximilian N.
• Format: Journal Article
• Language: English
• Published: Madison The American Astronomical Society 01.06.2020; IOP Publishing
• Subjects: Astronomy; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Exoplanet astronomy; Exoplanet systems; Extrasolar planets; Gas giant planets; GRAVITATION; MASS; Orbits; PHOTOMETRY; Planet detection; PLANETS; RADIAL VELOCITY; STARS; Stellar evolution; Stellar seismology; Transit; Transit photometry
• ISSN: 0004-6256; 1538-3881; 1538-3881
• DOI: 10.3847/1538-3881/ab84f2

The exoplanet HD 118203 b, orbiting a bright (V = 8.05) host star, was discovered using the radial velocity method by da Silva et al., but was not previously known to transit. Transiting Exoplanet Survey Satellite (TESS) photometry has revealed that this planet transits its host star. Nine planetary transits were observed by TESS, allowing us to measure the radius of the planet to be , and to calculate the planet mass to be . The host star is slightly evolved with an effective temperature of K and a surface gravity of . With an orbital period of days and an eccentricity of 0.314 0.017, the planet occupies a transitional regime between circularized hot Jupiters and more dynamically active planets at longer orbital periods. The host star is among the 10 brightest known to have transiting giant planets, providing opportunities for both planetary atmospheric and asteroseismic studies.