المؤلفون: Kanodia, Shubham, Cañas, Caleb I., Mahadevan, Suvrath, Ford, Eric B., Helled, Ravit, Anderson, Dana E., Boss, Alan, Cochran, William D., Delamer, Megan, Han, Te, Libby-Roberts, Jessica E., Lin, Andrea S. J., Müller, Simon, Robertson, Paul, Stefánsson, Guðmundur, Teske, Johanna

مصطلحات موضوعية: Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics

الوصف: Recent discoveries of transiting giant exoplanets around M-dwarf stars (GEMS), aided by the all-sky coverage of TESS, are starting to stretch theories of planet formation through the core-accretion scenario. Recent upper limits on their occurrence suggest that they decrease with lower stellar masses, with fewer GEMS around lower-mass stars compared to solar-type. In this paper, we discuss existing GEMS both through confirmed planets, as well as protoplanetary disk observations, and a combination of tests to reconcile these with theoretical predictions. We then introduce the \textit{Searching for GEMS} survey, where we utilize multi-dimensional nonparameteric statistics to simulate hypothetical survey scenarios to predict the required sample size of transiting GEMS with mass measurements to robustly compare their bulk-density with canonical hot-Jupiters orbiting FGK stars. Our Monte-Carlo simulations predict that a robust comparison requires about 40 transiting GEMS (compared to the existing sample of $\sim$ 15) with 5-$\sigma$ mass measurements. Furthermore, we discuss the limitations of existing occurrence estimates for GEMS, and provide a brief description of our planned systematic search to improve the occurrence rate estimates for GEMS.
Comment: 16 pages + references, including 7 figures. Accepted in AAS Journals

URL الوصول: http://arxiv.org/abs/2402.04946

المؤلفون: Jones, Sinclaire E., Stefansson, Gudmundur, Masuda, Kento, Libby-Roberts, Jessica E., Gardner, Cristilyn N., Holcomb, Rae, Beard, Corey, Robertson, Paul, Cañas, Caleb I., Mahadevan, Suvrath, Kanodia, Shubham, Lin, Andrea S. J., Kobulnicky, Henry A., Parker, Brock A., Bender, Chad F., Cochran, William D., Diddams, Scott A., Fernandes, Rachel B., Gupta, Arvind F., Halverson, Samuel, Hawley, Suzanne L., Hearty, Fred R., Hebb, Leslie, Kowalski, Adam, Lubin, Jack, Monson, Andrew, Ninan, Joe P., Ramsey, Lawrence, Roy, Arpita, Schwab, Christian, Terrien, Ryan C., Wisniewski, John

مصطلحات موضوعية: Astrophysics - Earth and Planetary Astrophysics

الوصف: We report the discovery of a close-in ($P_{\mathrm{orb}} = 3.349\:\mathrm{days}$) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby ($d=47.3\:\mathrm{pc}$) active M4 star, TOI-2015. We characterize the planet's properties using TESS photometry, precise near-infrared radial velocities (RV) with the Habitable-zone Planet Finder (HP) Spectrograph, ground-based photometry, and high-contrast imaging. A joint photometry and RV fit yields a radius $R_p~=~3.37_{-0.20}^{+0.15} \:\mathrm{R_\oplus}$, mass $m_p~=~16.4_{-4.1}^{+4.1}\:\mathrm{M_\oplus}$, and density $\rho_p~=~2.32_{-0.37}^{+0.38} \:\mathrm{g cm^{-3}}$ for TOI-2015b, suggesting a likely volatile-rich planet. The young, active host star has a rotation period of $P_{\mathrm{rot}}~=~8.7 \pm~0.9~\mathrm{days}$ and associated rotation-based age estimate of $1.1~\pm~0.1\:\mathrm{Gyr}$. Though no other transiting planets are seen in the TESS data, the system shows clear TTVs of super period $P_{\mathrm{sup}}~\approx~430\:\mathrm{days}$ and amplitude $\sim$$100\:\mathrm{minutes}$. After considering multiple likely period ratio models, we show an outer planet candidate near a 2:1 resonance can explain the observed TTVs while offering a dynamically stable solution. However, other possible two-planet solutions -- including 3:2 and 4:3 resonance -- cannot be conclusively excluded without further observations. Assuming a 2:1 resonance in the joint TTV-RV modeling suggests a mass of $m_b~=~13.3_{-4.5}^{+4.7}\:\mathrm{M_\oplus}$ for TOI-2015b and $m_c~=~6.8_{-2.3}^{+3.5}\:\mathrm{M_\oplus}$ for the outer candidate. Additional transit and RV observations will be beneficial to explicitly identify the resonance and further characterize the properties of the system.
Comment: 29 pages, 15 figures, 6 tables. Accepted for publication in The Astronomical Journal

URL الوصول: http://arxiv.org/abs/2310.11775

المؤلفون: Grant, David, Lewis, Nikole K., Wakeford, Hannah R., Batalha, Natasha E., Glidden, Ana, Goyal, Jayesh, Mullens, Elijah, MacDonald, Ryan J., May, Erin M., Seager, Sara, Stevenson, Kevin B., Valenti, Jeff A., Visscher, Channon, Alderson, Lili, Allen, Natalie H., Cañas, Caleb I., Colón, Knicole, Clampin, Mark, Espinoza, Néstor, Gressier, Amélie, Huang, Jingcheng, Lin, Zifan, Long, Douglas, Louie, Dana R., Peña-Guerrero, Maria, Ranjan, Sukrit, Sotzen, Kristin S., Valentine, Daniel, Anderson, Jay, Balmer, William O., Bellini, Andrea, Hoch, Kielan K. W., Kammerer, Jens, Libralato, Mattia, Mountain, C. Matt, Perrin, Marshall D., Pueyo, Laurent, Rickman, Emily, Rebollido, Isabel, Sohn, Sangmo Tony, van der Marel, Roeland P., Watkins, Laura L.

مصطلحات موضوعية: Astrophysics - Earth and Planetary Astrophysics

الوصف: Clouds are prevalent in many of the exoplanet atmospheres that have been observed to date. For transiting exoplanets, we know if clouds are present because they mute spectral features and cause wavelength-dependent scattering. While the exact composition of these clouds is largely unknown, this information is vital to understanding the chemistry and energy budget of planetary atmospheres. In this work, we observe one transit of the hot Jupiter WASP-17b with JWST's MIRI LRS and generate a transmission spectrum from 5-12 $\rm{\mu}$m. These wavelengths allow us to probe absorption due to the vibrational modes of various predicted cloud species. Our transmission spectrum shows additional opacity centered at 8.6 $\rm{\mu}$m, and detailed atmospheric modeling and retrievals identify this feature as SiO$_2$(s) (quartz) clouds. The SiO$_2$(s) clouds model is preferred at 3.5-4.2$\sigma$ versus a cloud-free model and at 2.6$\sigma$ versus a generic aerosol prescription. We find the SiO$_2$(s) clouds are comprised of small ${\sim}0.01$ $\rm{\mu}$m particles, which extend to high altitudes in the atmosphere. The atmosphere also shows a depletion of H$_2$O, a finding consistent with the formation of high-temperature aerosols from oxygen-rich species. This work is part of a series of studies by our JWST Telescope Scientist Team (JWST-TST), in which we will use Guaranteed Time Observations to perform Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy (DREAMS).
Comment: 19 pages, 7 figures, accepted for publication in ApJL

URL الوصول: http://arxiv.org/abs/2310.08637

المؤلفون: Fitzmaurice, Evan, Stefánsson, Gudmundur, Kavanagh, Robert D., Mahadevan, Suvrath, Cañas, Caleb I., Winn, Joshua N., Robertson, Paul, Ninan, Joe P., Albrecht, Simon, Callingham, J. R., Cochran, William D., Delamer, Megan, Kanodia, Shubham, Lin, Andrea S. J., Marcussen, Marcus L., Pope, Benjamin J. S., Ramsey, Lawrence W., Roy, Arpita, Vedantham, Harish, Wright, Jason T.

مصطلحات موضوعية: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics

الوصف: We characterize the LHS 1610 system, a nearby ($d=9.7$ pc) M5 dwarf hosting a brown dwarf in a $10.6$ day, eccentric ($e \sim 0.37$) orbit. A joint fit of the available Gaia two-body solution, discovery radial velocities (RVs) from TRES, and new RVs obtained with the Habitable-zone Planet Finder, yields an orbital inclination of $117.2\pm0.9^\circ$ and a mass constraint of $50.9\pm0.9$ M$_J$. This gives LHS 1610 b the second most precise mass of brown dwarfs orbiting M stars within 25pc. We highlight a discrepancy between the Gaia two-body solution eccentricity ($e=0.52 \pm 0.03$) and that from the RVs ($e=0.3702\pm0.0003$), which requires the astrometric time-series release (Gaia DR4) for further diagnostics. With a flare rate of $0.28\pm 0.07$ flares/day from TESS photometry, and a rotation period of $84 \pm 8$ days, LHS 1610 joins other mid M stars -- including Proxima Centauri and YZ Ceti -- as nearby mid M dwarfs with flare rates on the higher end for their long rotation periods. These stars are promising candidates for searching for sub-Alfv\'enic star-companion interactions, raising the question whether LHS 1610 b could be driving the flares on its host star. However, the available TESS photometry is insufficient to confirm or rule out any orbital phase-dependence of the flares. We show that the LHS 1610 system, as a nearby mid M star with a large, short-period companion, is a promising target to look for evidence of star-companion interactions or aural emission from the brown dwarf at radio wavelengths.
Comment: 24 pages, 7 figures, 3 tables. Submitted to AAS Journals on Oct 11, 2023

URL الوصول: http://arxiv.org/abs/2310.07827

المؤلفون: Schutte, Maria C., Hebb, Leslie, Wisniewski, John P., Canas, Caleb I., Libby-Roberts, Jessica E., Lin, Andrea S. J., Robertson, Paul, Stefansson, Gudmundur

مصطلحات موضوعية: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics

الوصف: Using simultaneous multi-filter observations during the transit of an exoplanet around a K dwarf star, we determine the temperature of a starspot through modeling the radius and position with wavelength-dependent spot contrasts. We model the spot using the starspot modeling program STarSPot (STSP), which uses the transiting companion as a knife-edge probe of the stellar surface. The contrast of the spot, i.e. the ratio of the integrated flux of a darker spot region to the star's photosphere, is calculated for a range of filters and spot temperatures. We demonstrate this technique using simulated data of HAT-P-11, a K dwarf (T = 4780 K) with well-modeled starspot properties for which we obtained simultaneous multi-filter transits using LCO's MuSCAT3 instrument on the 2-meter telescope at Haleakala Observatory which allows for simultaneous, multi-filter, diffuser assisted high-precision photometry. We determine the average (i.e. a combination of penumbra and umbra) spot temperature for HAT-P-11's spot complexes is 4500 K $\pm$ 100 K using this technique. We also find for our set of filters that comparing the SDSS g' and i' filters maximizes the signal difference caused by a large spot in the transit. Thus, this technique allows for the determination of the average spot temperature using only one spot occultation in transit and can provide simultaneous information on the spot temperature and spot properties.
Comment: 14 pages, 9 figures, accepted to AJ

URL الوصول: http://arxiv.org/abs/2307.16015

المؤلفون: Delamer, Megan, Kanodia, Shubham, Cañas, Caleb I., Müller, Simon, Helled, Ravit, Lin, Andrea S. J., Libby-Roberts, Jessica E., Gupta, Arvind F., Mahadevan, Suvrath, Teske, Johanna, Butler, R. Paul, Yee, Samuel W., Crane, Jeffrey D., Shectman, Stephen, Osip, David, Beletsky, Yuri, Monson, Andrew, Alvarado-Montes, Jaime A., Bender, Chad F., Dong, Jiayin, Han, Te, Ninan, Joe P., Robertson, Paul, Roy, Arpita, Schwab, Christian, Stefánsson, Guðmundur, Wright, Jason T.

مصطلحات موضوعية: Astrophysics - Earth and Planetary Astrophysics

الوصف: We confirm TOI-4201 b as a transiting Jovian mass planet orbiting an early M dwarf discovered by the Transiting Exoplanet Survey Satellite. Using ground based photometry and precise radial velocities from NEID and the Planet Finder Spectrograph, we measure a planet mass of 2.59$^{+0.07}_{-0.06}$ M$_{J}$, making this one of the most massive planets transiting an M-dwarf. The planet is $\sim$0.4\% the mass of its 0.63 M$_{\odot}$ host and may have a heavy element mass comparable to the total dust mass contained in a typical Class II disk. TOI-4201 b stretches our understanding of core-accretion during the protoplanetary phase, and the disk mass budget, necessitating giant planet formation to either take place much earlier in the disk lifetime, or perhaps through alternative mechanisms like gravitational instability.
Comment: To be submitted to AAS journals on 14th July 2023

URL الوصول: http://arxiv.org/abs/2307.06880

المؤلفون: Powers, Luke C., Libby-Roberts, Jessica, Lin, Andrea S. J., Cañas, Caleb I., Kanodia, Shubham, Mahadevan, Suvrath, Ninan, Joe P., Stefánsson, Guðmundur, Gupta, Arvind F., Jones, Sinclaire, Kobulnicky, Henry A., Monson, Andrew, Parker, Brock A., Swaby, Tera N., Bender, Chad F., Cochran, William D., Hebb, Leslie, Metcalf, Andrew J., Robertson, Paul, Schwab, Christian, Wisniewski, John, Wright, Jason T.

المصدر: The Astronomical Journal, Volume 166, Number 2, Year 2023

مصطلحات موضوعية: Astrophysics - Earth and Planetary Astrophysics

الوصف: Using both ground-based transit photometry and high-precision radial velocity (RV) spectroscopy, we confirm the planetary nature of TOI-3785 b. This transiting Neptune orbits an M2-Dwarf star with a period of ~4.67 days, a planetary radius of 5.14 +/- 0.16 Earth Radii, a mass of 14.95 +4.10, -3.92 Earth Masses, and a density of 0.61 +0.18, -0.17 g/cm^3. TOI-3785 b belongs to a rare population of Neptunes (4 Earth Radii < Rp < 7 Earth Radii) orbiting cooler, smaller M-dwarf host stars, of which only ~10 have been confirmed. By increasing the number of confirmed planets, TOI-3785 b offers an opportunity to compare similar planets across varying planetary and stellar parameter spaces. Moreover, with a high transmission spectroscopy metric (TSM) of ~150 combined with a relatively cool equilibrium temperature of 582 +/- 16 K and an inactive host star, TOI-3785 b is one of the more promising low-density M-dwarf Neptune targets for atmospheric follow-up. Future investigation into atmospheric mass loss rates of TOI-3785 b may yield new insights into the atmospheric evolution of these low-mass gas planets around M-dwarfs.
Comment: 22 pages, 6 figures, 6 tables, Published to AJ. arXiv admin note: text overlap with arXiv:2301.10837

URL الوصول: http://arxiv.org/abs/2304.04730

المؤلفون: Lambert, Mika, Bender, Chad F., Kanodia, Shubham, Cañas, Caleb I., Monson, Andrew, Stefánsson, Guðmundur, Cochran, William D., Everett, Mark E., Gupta, Arvind F., Hearty, Fred, Kobulnicky, Henry A., Libby-Roberts, Jessica E., Lin, Andrea S. J., Mahadevan, Suvrath, Ninan, Joe P., Parker, Brock A., Robertson, Paul, Schwab, Christian, Terrien, Ryan C.

مصطلحات موضوعية: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics

الوصف: The TESS mission detected a companion orbiting TIC 71268730, categorized it as a planet candidate, and designated the system TOI-5375. Our follow-up analysis using radial velocity data from the Habitable-zone Planet Finder (HPF), photometric data from Red Buttes Observatory (RBO), and speckle imaging with NN-EXPLORE Exoplanet Stellar Speckle Imager (NESSI) determined that the companion is a very low mass star (VLMS) near the hydrogen-burning mass limit with a mass of 0.080$\pm{0.002} M_{\Sun}$ ($83.81\pm{2.10} M_{J}$), a radius of 0.1114$^{+0.0048}_{-0.0050} R_{\Sun}$ (1.0841$^{0.0467}_{0.0487} R_{J}$), and brightness temperature of $2600\pm{70}$ K. This object orbits with a period of 1.721553$\pm{0.000001}$ days around an early M dwarf star ($0.62\pm{0.016}M_{\Sun}$). TESS photometry shows regular variations in the host star's TESS light curve, which we interpreted as activity-induced variation of $\sim$2\%, and used this variability to measure the host star's stellar rotation period of 1.9716$^{+0.0080}_{-0.0083}$ days. The TOI-5375 system provides tight constraints on stellar models of low-mass stars at the hydrogen-burning limit and adds to the population in this important region.
Comment: 15 pages, 8 figures, Accepted to the Astronomical Journal

URL الوصول: http://arxiv.org/abs/2303.16193

المؤلفون: Cañas, Caleb I., Kanodia, Shubham, Libby-Roberts, Jessica, Lin, Andrea S. J., Schutte, Maria, Powers, Luke, Jones, Sinclaire, Monson, Andrew, Wang, Songhu, Stefánsson, Guðmundur, Cochran, William D., Robertson, Paul, Mahadevan, Suvrath, Kowalski, Adam F., Wisniewski, John, Parker, Brock A., Larsen, Alexander, Chapman, Franklin A. L., Kobulnicky, Henry A., Gupta, Arvind F., Everett, Mark E., Penprase, Bryan Edward, Zeimann, Gregory, Beard, Corey, Bender, Chad F., Colón, Knicole D., Diddams, Scott A., Fredrick, Connor, Halverson, Samuel, Ninan, Joe P., Ramsey, Lawrence W., Roy, Arpita, Schwab, Christian

المصدر: AJ, 166, 30 (2023)

مصطلحات موضوعية: Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics

الوصف: We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs with stellar companions at wide separations. TOI-3984 A ($J=11.93$) is an M4 dwarf hosting a short-period ($4.353326 \pm 0.000005$ days) gas giant ($M_p=0.14\pm0.03~\mathrm{M_{J}}$ and $R_p=0.71\pm0.02~\mathrm{R_{J}}$) with a wide separation white dwarf companion. TOI-5293 A ($J=12.47$) is an M3 dwarf hosting a short-period ($2.930289 \pm 0.000004$ days) gas giant ($M_p=0.54\pm0.07~\mathrm{M_{J}}$ and $R_p=1.06\pm0.04~\mathrm{R_{J}}$) with a wide separation M dwarf companion. We characterize both systems using a combination of ground-based and space-based photometry, speckle imaging, and high-precision radial velocities from the Habitable-zone Planet Finder and NEID spectrographs. TOI-3984 A b ($T_{eq}=563\pm15$ K and $\mathrm{TSM}=138_{-27}^{+29}$) and TOI-5293 A b ($T_{eq}=675_{-30}^{+42}$ K and $\mathrm{TSM}=92\pm14$) are two of the coolest gas giants among the population of hot Jupiter-sized gas planets orbiting M dwarfs and are favorable targets for atmospheric characterization of temperate gas giants and three-dimensional obliquity measurements to probe system architecture and migration scenarios.
Comment: Published in AJ, 46 pages, 16 figures, 6 tables, updated to reflect published version. arXiv admin note: substantial text overlap with arXiv:2201.09963

URL الوصول: http://arxiv.org/abs/2302.07714

المؤلفون: Cañas, Caleb I., Bender, Chad F., Mahadevan, Suvrath, Bizyaev, Dmitry, De Lee, Nathan, Fleming, Scott W., Hearty, Fred, Majewski, Steven R., Nitschelm, Christian, Schneider, Donald P., Serna, Javier, Stassun, Keivan G., Stefánsson, Guðmundur, Stringfellow, Guy S., Wilson, John C.

المصدر: ApJS (2023), 265, 50

مصطلحات موضوعية: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics

الوصف: We report the characterization of 28 low-mass ($0.02\mathrm{~M_\odot}\le\mathrm{~M_{2}}\le0.25\mathrm{~M_\odot}$) companions to $\textit{Kepler}$ objects of interest (KOIs), eight of which were previously designated confirmed planets. These objects were detected as transiting companions to Sun-like stars (G and F dwarfs) by the $\textit{Kepler}$ mission and are confirmed as single-lined spectroscopic binaries in the current work using the northern multiplexed Apache Point Observatory Galactic Evolution Experiment near-infrared spectrograph (APOGEE-N) as part of the third and fourth Sloan Digital Sky Surveys. We have observed hundreds of KOIs using APOGEE-N and collected a total of 43,175 spectra with a median of 19 visits and a median baseline of $\sim1.9$ years per target. We jointly model the $\textit{Kepler}$ photometry and APOGEE-N radial velocities to derive fundamental parameters for this subset of 28 transiting companions. The radii for most of these low-mass companions are over-inflated (by $\sim10\%$) when compared to theoretical models. Tidally locked M dwarfs on short period orbits show the largest amount of inflation, but inflation is also evident for companions that are well separated from the host star. We demonstrate that APOGEE-N data provides reliable radial velocities when compared to precise high-resolution spectrographs that enable detailed characterization of individual systems and the inference of orbital elements for faint ($H>12$) KOIs. The data from the entire APOGEE-KOI program is public and presents an opportunity to characterize an extensive subset of the binary population observed by $\textit{Kepler}$.
Comment: 98 pages (include 56 for the figure sets), 10 tables, 7 figures, 2 figure sets, accepted for publication in ApJS

URL الوصول: http://arxiv.org/abs/2302.07713