|
|
Dong, J. Y., Huang, C. X., Dawson, R. I., Foreman-Mackey, D., Collins, K. A., Quinn, S. N., et al. (2021). Warm Jupiters in TESS Full-frame Images: A Catalog and Observed Eccentricity Distribution for Year 1. Astrophys. J. Suppl. Ser., 255(1), 6.
Abstract: Warm Jupiters-defined here as planets larger than 6 Earth radii with orbital periods of 8-200 days-are a key missing piece in our understanding of how planetary systems form and evolve. It is currently debated whether Warm Jupiters form in situ, undergo disk or high-eccentricity tidal migration, or have a mixture of origin channels. These different classes of origin channels lead to different expectations for Warm Jupiters' properties, which are currently difficult to evaluate due to the small sample size. We take advantage of the Transiting Exoplanet Survey Satellite (TESS) survey and systematically search for Warm Jupiter candidates around main-sequence host stars brighter than the TESS-band magnitude of 12 in the full-frame images in Year 1 of the TESS Prime Mission data. We introduce a catalog of 55 Warm Jupiter candidates, including 19 candidates that were not originally released as TESS objects of interest by the TESS team. We fit their TESS light curves, characterize their eccentricities and transit-timing variations, and prioritize a list for ground-based follow-up and TESS Extended Mission observations. Using hierarchical Bayesian modeling, we find the preliminary eccentricity distributions of our Warm-Jupiter-candidate catalog using a beta distribution, a Rayleigh distribution, and a two-component Gaussian distribution as the functional forms of the eccentricity distribution. Additional follow-up observations will be required to clean the sample of false positives for a full statistical study, derive the orbital solutions to break the eccentricity degeneracy, and provide mass measurements.
|
|
|
|
Heitzmann, A., Zhou, G., Quinn, S. N., Huang, C. X., Dong, J. Y., Bouma, L. G., et al. (2023). TOI-4562b: A Highly Eccentric Temperate Jupiter Analog Orbiting a Young Field Star. Astron. J., 165(3), 121.
Abstract: We report the discovery of TOI-4562b (TIC-349576261), a Jovian planet orbiting a young F7V-type star, younger than the Praesepe/Hyades clusters (< 700 Myr). This planet stands out because of its unusually long orbital period for transiting planets with known masses (Porb = 225.11781(- 0.00022) (+0.00025 )days) and because it has a substantial eccentricity (e = 0.76(- 0.02) (+0.02)). The location of TOI-4562 near the southern continuous viewing zone of TESS allowed observations throughout 25 sectors, enabling an unambiguous period measurement from TESS alone. Alongside the four available TESS transits, we performed follow-up photometry using the South African Astronomical Observatory node of the Las Cumbres Observatory and spectroscopy with the CHIRON spectrograph on the 1.5 m SMARTS telescope. We measure a radius of 1.118 (+0.013) (-0.014) R(J )and a mass of 2.30(-0.47)(+0.48)M(J) for TOI-4562b. The radius of the planet is consistent with contraction models describing the early evolution of the size of giant planets. We detect tentative transit timing variations at the similar to 20 minutes level from five transit events, favoring the presence of a companion that could explain the dynamical history of this system if confirmed by future follow-up observations. With its current orbital configuration, tidal timescales are too long for TOI-4562b to become a hot Jupiter via high eccentricity migration though it is not excluded that interactions with the possible companion could modify TOI4562b's eccentricity and trigger circularization. The characterization of more such young systems is essential to set constraints on models describing giant-planet evolution.
|
|
|
|
Hobson, M. J., Trifonov, T., Henning, T., Jordan, A., Rojas, F., Espinoza, N., et al. (2023). Alert Results TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica 41 of 41 TOI-199 b: A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica. Astron. J., 166(5), 201.
Abstract: 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.
|
|
|
|
Jenkins, J. S., Diaz, M. R., Kurtovic, N. T., Espinoza, N., Vines, J. I., Rojas, P. A. P., et al. (2020). An ultrahot Neptune in the Neptune desert. Nat. Astron., 4(12), 1148–1157.
Abstract: About 1 out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultrashort-period planet(1,2). All of the previously known ultrashort-period planets are either hot Jupiters, with sizes above 10 Earth radii (R-circle plus), or apparently rocky planets smaller than 2 R-circle plus. Such lack of planets of intermediate size (the `hot Neptune desert') has been interpreted as the inability of low-mass planets to retain any hydrogen/ helium (H/He) envelope in the face of strong stellar irradiation. Here we report the discovery of an ultrashort-period planet with a radius of 4.6 R-circle plus and a mass of 29 M-circle plus, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite(3) revealed transits of the bright Sun-like star LTT 9779 every 0.79 days. The planet's mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0(-2.9)(+2.7) % of the total mass. With an equilibrium temperature around 2,000 K, it is unclear how this `ultrahot Neptune' managed to retain such an envelope. Follow-up observations of the planet's atmosphere to better understand its origin and physical nature will be facilitated by the star's brightness (V-mag = 9.8).
|
|
|
|
Jones, M. I., Reinarz, Y., Brahm, R.., Tala Pinto, M., Eberhardt, J., Rojas, F., et al. (2024). A long-period transiting substellar companion in the super-Jupiters to brown dwarfs mass regime and a prototypical warm-Jupiter detected by TESS. Astron. Astrophys., 683, A192.
Abstract: 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.
|
|
|
|
Sha, L. Z., Vanderburg, A. M., Huang, C. X., Armstrong, D. J., Brahm, R., Giacalone, S., et al. (2023). TESS spots a mini-neptune interior to a hot saturn in the TOI-2000 system. Mon. Not. Roy. Astron. Soc., 524(1), 1113–1138.
Abstract: Hot jupiters (P < 10 d, M > 60 M.) are almost always found alone around their stars, but four out of hundreds known have inner companion planets. These rare companions allow us to constrain the hot jupiter's formation history by ruling out high-eccentricity tidal migration. Less is known about inner companions to hot Saturn-mass planets. We report here the discovery of the TOI-2000 system, which features a hot Saturn-mass planet with a smaller inner companion. The mini-neptune TOI-2000 b (2.70 +/- 0.15 R-circle plus, 11.0 +/- 2.4 M.) is in a 3.10-d orbit, and the hot saturn TOI-2000 c (8.14(+0.31) (-0.30) R-circle plus, 81.7(-4.6)(+4.7) M.) is in a 9.13-d orbit. Both planets transit their host star TOI-2000 (TIC 371188886, V = 10.98, TESS magnitude = 10.36), a metal-rich ([Fe/H] = 0.439 (+0.041)(-0.043)) G dwarf 173 pc away. TESS observed the two planets in sectors 9-11 and 36-38, and we followed up with groundbased photometry, spectroscopy, and speckle imaging. Radial velocities from CHIRON, FEROS, and HARPS allowed us to confirm both planets by direct mass measurement. In addition, we demonstrate constraining planetary and stellar parameters with MIST stellar evolutionary tracks through Hamiltonian Monte Carlo under the PYMC framework, achieving higher sampling efficiency and shorter run time compared to traditional Markov chain Monte Carlo. Having the brightest host star in the V band among similar systems, TOI-2000 b and c are superb candidates for atmospheric characterization by the JWST, which can potentially distinguish whether they formed together or TOI-2000 c swept along material during migration to form TOI-2000 b.
|
|
|
|
Trifonov, T., Brahm, R., Espinoza, N., Henning, T., Jordan, A., Nesvorny, D., et al. (2021). A Pair of Warm Giant Planets near the 2:1 Mean Motion Resonance around the K-dwarf Star TOI-2202*. Astron. J., 162(6), 283.
Abstract: TOI-2202 b is a transiting warm Jovian-mass planet with an orbital period of P = 11.91 days identified from the Full Frame Images data of five different sectors of the TESS mission. Ten TESS transits of TOI-2202 b combined with three follow-up light curves obtained with the CHAT robotic telescope show strong transit timing variations (TTVs) with an amplitude of about 1.2 hr. Radial velocity follow-up with FEROS, HARPS, and PFS confirms the planetary nature of the transiting candidate (a (b) = 0.096 +/- 0.001 au, m (b) = 0.98 +/- 0.06 M (Jup)), and a dynamical analysis of RVs, transit data, and TTVs points to an outer Saturn-mass companion (a (c) = 0.155 +/- 0.002 au, m (c) = 0.37 +/- 0.10 M (Jup)) near the 2:1 mean motion resonance. Our stellar modeling indicates that TOI-2202 is an early K-type star with a mass of 0.82 M (circle dot), a radius of 0.79 R (circle dot), and solar-like metallicity. The TOI-2202 system is very interesting because of the two warm Jovian-mass planets near the 2:1 mean motion resonance, which is a rare configuration, and their formation and dynamical evolution are still not well understood.
|
|
