Browsing by Author "Jones, Matias I."

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    A long-period transiting substellar companion in the super-Jupiters to brown dwarfs mass regime and a prototypical warm-Jupiter detected by TESS
    (2024) Jones, Matias I.; Reinarz, Yared; Brahm, Rafael; Tala Pinto, Marcelo; Eberhardt, Jan; Rojas, Felipe; Triaud, Amaury H. M. J.; Gupta, Arvind F.; Ziegler, Carl; Hobson, Melissa J.; Jordan, Andres; Henning, Thomas; Trifonov, Trifon; Schlecker, Martin; Espinoza, Nestor; Torres-Miranda, Pascal; Sarkis, Paula; Ulmer-Moll, Solene; Lendl, Monika; Uzundag, Murat; Moyano, Maximiliano; Hesse, Katharine; Caldwell, Douglas A.; Shporer, Avi; Lund, Michael B.; Jenkins, Jon M.; Seager, Sara; Winn, Joshua N.; Ricker, George R.; Burke, Christopher J.; Figueira, Pedro; Psaridi, Angelica; Al Moulla, Khaled; Mounzer, Dany; Standing, Matthew R.; Martin, David V.; Dransfield, Georgina; Baycroft, Thomas; Dragomir, Diana; Boyle, Gavin; Suc, Vincent; Mann, Andrew W.; Timmermans, Mathilde; Ducrot, Elsa; Hooton, Matthew J.; Zuniga-Fernandez, Sebastian; Sebastian, Daniel; Gillon, Michael; Queloz, Didier; Carson, Joe; Lissauer, Jack J.
    We report on the confirmation and follow-up characterization of two long-period transiting substellar companions on low-eccentricity orbits around TIC 4672985 and TOI-2529, whose transit events were detected by the TESS space mission. Ground-based photometric and spectroscopic follow-up from different facilities, confirmed the substellar nature of TIC 4672985 b, a massive gas giant in the transition between the super-Jupiters and brown dwarfs mass regime. From the joint analysis we derived the following orbital parameters: P = 69.0480(-0.0005)(+0.0004) d, M-p = 12.74(-1.01)(+1.01) M-J, R-p = 1.026(-0.067)(+0.065) R-J and e = 0.018(-0.004)(+0.004). In addition, the RV time series revealed a significant trend at the similar to 350 m s(-1) yr(-1) level, which is indicative of the presence of a massive outer companion in the system. TIC 4672985 b is a unique example of a transiting substellar companion with a mass above the deuterium-burning limit, located beyond 0.1 AU and in a nearly circular orbit. These planetary properties are difficult to reproduce from canonical planet formation and evolution models. For TOI-2529 b, we obtained the following orbital parameters: P = 64.5949(-0.0003)(+0.0003) d, M-p = 2.340(-0.195)(+0.197) M-J, R-p = 1.030(-0.050)(+0.050) R-J and e = 0.021(-0.015)(+0.024), making this object a new example of a growing population of transiting warm giant planets.
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    Evidence of extra mixing in field giants as traced by the lithium and carbon isotope ratio
    (2023) Aguilera-Gomez, Claudia; Jones, Matias I.; Chaname, Julio
    Context. Although not predicted by standard stellar evolution, the surface abundance of light elements, such as lithium (Li), carbon, and nitrogen, changes during the red giant branch (RGB) as a result of extra mixing. This is usually associated with thermohaline mixing acting after the RGB bump. Peculiar Li-enriched RGB stars might also be related to either enhanced mixing or pollution from external sources.Aims. We measure the Li abundance and carbon isotopic ratio C-12/C-13 in a sample of 166 field red giants with -0.3 <= [Fe/H] <= 0.2, targeted by the EXPRESS radial velocity program to analyze the effects of extra mixing.Methods. We measured the abundances with spectral synthesis using high-quality spectra. Multiple-epoch observations needed for exoplanet detection were used to decrease the effects of telluric contamination in C-12/C-13 measurements.Results. Due to the prevalence of upper limits, the Li abundance pattern is complicated to interpret, but the comparison between RGB and core He-burning giants shows effects of mixing consistent with thermohaline. The most Li-enriched giant in the sample, classified as a RGB star close to the RGB bump, has low C-12/C-13. Given that the C-12/C-13 should not be affected by planet engulfment, this does not seem to be the source of the high Li. There is a decreasing correlation between mass and C-12/C-13 in the RGB and an increasing correlation in the horizontal branch, which, once again, is consistent with thermohaline mixing. Our data also show a correlation between C-12/C-13 and [Fe/H]. There is no evident impact of binarity either on Li or on C-12/C-13.Conclusions. Our sample shows behavior consistent with additional mixing acting after the RGB bump. The C-12/C-13 adds new clues which can be used to describe extra mixing, and it could well be the best tool to study mixing in giants. Additional measurements of C-12/C-13 in field stars would greatly improve our ability to compare data with models and understand mixing mechanisms.
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    Three Long-period Transiting Giant Planets from TESS*
    (2023) Brahm, Rafael; Ulmer-Moll, Solene; Hobson, Melissa J.; Jordan, Andres; Henning, Thomas; Trifonov, Trifon; Jones, Matias I.; Schlecker, Martin; Espinoza, Nestor; Rojas, Felipe I.; Torres, Pascal; Sarkis, Paula; Tala, Marcelo; Eberhardt, Jan; Kossakowski, Diana; Munoz, Diego J.; Hartman, Joel D.; Boyle, Gavin; Suc, Vincent; Bouchy, Francois; Deline, Adrien; Chaverot, Guillaume; Grieves, Nolan; Lendl, Monika; Suarez, Olga; Guillot, Tristan; Triaud, Amaury H. M. J.; Crouzet, Nicolas; Dransfield, Georgina; Cloutier, Ryan; Barkaoui, Khalid; Schwarz, Rick P.; Stockdale, Chris; Harris, Mallory; Mireles, Ismael; Evans, Phil; Mann, Andrew W.; Ziegler, Carl; Dragomir, Diana; Villanueva, Steven; Mordasini, Christoph; Ricker, George; Vanderspek, Roland; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Vezie, Michael; Youngblood, Allison; Daylan, Tansu; Collins, Karen A.; Caldwell, Douglas A.; Ciardi, David R.; Palle, Enric; Murgas, Felipe
    We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single-transit events in the light curves generated from the full-frame images of the Transiting Exoplanet Survey Satellite. Follow-up radial velocity measurements and additional light curves were used to determine the orbital periods and confirm the planetary nature of the candidates. The planets orbit slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has a mass of M ( P ) = 0.30 +/- 0.04 M (J), a radius of R ( P ) = 1.00 +/- 0.02 R (J), and a low-eccentricity orbit (e = 0.15 +/- 0.05) with a period of P = 30.08364 +/- 0.00005 days. TOI 2338b has a mass of M ( P ) = 5.98 +/- 0.20 M (J), a radius of R ( P ) = 1.00 +/- 0.01 R (J), and a highly eccentric orbit (e = 0.676 +/- 0.002) with a period of P = 22.65398 +/- 0.00002 days. Finally, TOI 2589b has a mass of M ( P ) = 3.50 +/- 0.10 M (J), a radius of R ( P ) = 1.08 +/- 0.03 R (J), and an eccentric orbit (e = 0.522 +/- 0.006) with a period of P = 61.6277 +/- 0.0002 days. TOI 4406b and TOI 2338b are enriched in metals compared to their host stars, while the structure of TOI 2589b is consistent with having similar metal enrichment to its host star.
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    TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica
    (2023) Hobson, Melissa J.; Trifonov, Trifon; Henning, Thomas; Jordan, Andres; Rojas, Felipe; Espinoza, Nestor; Brahm, Rafael; Eberhardt, Jan; Jones, Matias I.; Mekarnia, Djamel; Kossakowski, Diana; Schlecker, Martin; Pinto, Marcelo Tala; Torres Miranda, Pascal Jose; Abe, Lyu; Barkaoui, Khalid; Bendjoya, Philippe; Bouchy, Francois; Buttu, Marco; Carleo, Ilaria; Collins, Karen A.; Colon, Knicole D.; Crouzet, Nicolas; Dragomir, Diana; Dransfield, Georgina; Gasparetto, Thomas; Goeke, Robert F.; Guillot, Tristan; Guenther, Maximilian N.; Howard, Saburo; Jenkins, Jon M.; Korth, Judith; Latham, David W.; Lendl, Monika; Lissauer, Jack J.; Mann, Christopher R.; Mireles, Ismael; Ricker, George R.; Saesen, Sophie; Schwarz, Richard P.; Seager, S.; Sefako, Ramotholo; Shporer, Avi; Stockdale, Chris; Suarez, Olga; Tan, Thiam-Guan; J. Triaud, Amaury H. M.; Ulmer-Moll, Solene; Vanderspek, Roland; Winn, Joshua N.; Wohler, Bill; Zhou, George
    We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5 hr long transit, PEST, Hazelwood, and LCO; space photometry from NEOSSat; and radial velocities (RVs) from FEROS, HARPS, CORALIE, and CHIRON. Orbiting a late G-type star, TOI-199 b has a 104.854-0.002+0.001day period, a mass of 0.17 +/- 0.02 M J, and a radius of 0.810 +/- 0.005 R J. It is the first warm exo-Saturn with a precisely determined mass and radius. The TESS and ASTEP transits show strong transit timing variations (TTVs), pointing to the existence of a second planet in the system. The joint analysis of the RVs and TTVs provides a unique solution for the nontransiting companion TOI-199 c, which has a period of 273.69-0.22+0.26days and an estimated mass of 0.28-0.01+0.02MJ . This period places it within the conservative habitable zone.