arXiv subjects

G. Conzo

Publications and source records attributed to G. Conzo.

7 recordsLinked to original sources

arXiv2026

Detection and characterization of the temperate super-earth Gliese 48 b

Gliese 48 is an M3.5V red dwarf exhibiting significant magnetic activity and a stellar rotation period of 51.5 d. In this work, we present a systematic re-analysis of radial velocities (RV) from CARMENES and decade-long HIRES observations, integrated with TESS space-based photometry. We identify a planet of undetermined composition, Gliese 48 b, with an orbital period $P = 39.6299 \pm 0.29$ d and a minimum mass $M \sin i = 8.11 \pm 1.63 M_{\oplus}$. The planetary nature of the signal is confirmed by its temporal coherence over a 15-year baseline and its achromaticity between visible and near-infrared channels. TESS photometry from Sectors 18, 19, 24, and 25 (218.6 d total baseline, 66,983 cadences) reveals no transit at $P = 39.63$ d (FAP $> 10\%$, BLS). An injection-and-recovery test demonstrates that a 1287 ppm transit signal corresponding to a minimum-radius $1.69 R_{\oplus}$ planet would have been detected with Signal-to-Pink-Noise Ratio SPNR $> 7$, ruling out a transiting geometry with high confidence. The orbital inclination is constrained to $i < 89.3^{\circ}$. With an incident stellar flux $S_{\rm eff} \approx 0.889 S_{\oplus}$ and bolometric luminosity $L_* = 0.0273 \pm 0.0023 L_{\odot}$, Gliese 48 b lies near the inner edge of the Conservative Habitable Zone and within the Optimistic HZ, making it one of the most astrobiologically compelling temperate Super-Earths orbiting an M-dwarf.

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arXiv2025

ExoClock Project IV: A homogeneous catalogue of 620 updated exoplanet ephemerides

The ExoClock project is an open platform aiming to monitor exoplanets by integrating observations from space and ground based telescopes. This study presents an updated catalogue of 620 exoplanet ephemerides, integrating 30000 measurements from ground-based telescopes (the ExoClock network), literature, and space telescopes (Kepler, K2 and TESS). The updated catalogue includes 277 planets from TESS which require special observing strategies due to their shallow transits or bright host stars. This study demonstrates that data from larger telescopes and the employment of new methodologies such as synchronous observations with small telescopes, are capable of monitoring special cases of planets. The new ephemerides show that 45% of the planets required an update while the results show an improvement of one order of magnitude in prediction uncertainty. The collective analysis also enabled the identification of new planets showing TTVs, highlighting the importance of extensive observing coverage. Developed in the context of the ESA's Ariel space mission, with the goal of delivering a catalogue with reliable ephemerides to increase the mission efficiency, ExoClock's scope and service have grown well beyond the remit of Ariel. The ExoClock project has been operating in the framework of open science, and all tools and products are accessible to everyone within academia and beyond, to support efficient scheduling of future exoplanet observations, especially from larger telescopes where the pressure for time allocation efficiency is higher (Ariel, JWST, VLT, ELT, Subaru etc). The inclusion of diverse audiences in the process and the collaborative mode not only foster democratisation of science but also enhance the quality of the results.

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arXiv2025

Characterization of the Visual Binary TOI-6883AB and its dynamical implications for the planetary companion TOI-6883Ab

We demonstrate that TOI-6883 is a physically bound visual binary system composed of two solar-type stars, TOI-6883A (TIC 393818343) and TOI-6883B (TIC 393818340), initially regarded as a single star hosting the exoplanet TOI-6883b. Gaia DR3 astrometry shows that both stars have nearly identical parallaxes 10.6 mas, consistent proper motions, and a projected separation of 616 AU, confirming their binary nature. Using astrometric and photometric data, we estimate the stellar masses, physical separation, and an orbital period of 15,000 years. The system is energetically bound. We revise the planet designation to TOI-6883Ab to reflect stellar multiplicity. We evaluate the impact of the binary companion on planetary stability and find the planet's orbit to be long-term stable, although Kozai-Lidov perturbations remain possible. Further astrometric and photometric follow-up will be essential to better constrain the binary orbit and assess potential dynamical influences on the planetary architecture.

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arXiv2024

TIC 393818343 c: Discovery and characterization of a Neptune-like planet in the Delphinus constellation

We report on the statistical confirmation of a second planet inside the TIC 393818343 system. The first planet TIC 393818343 b has been confirmed and classified as a Warm Jupiter planet with a period of P = (16.24921 +- 0.00003) days. The second planet in the system has an orbital period of P = (7.8458 +- 0.0023) days and orbits 2.05 times closer to its host star. The second planet was initially spotted by the Las Cumbres Observatory (LCOGT) and amateur astronomers. This Super-Neptunian exoplanet marks TIC 393818343 as a multi-planetary system.

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arXiv2023

Candidate triple-star system with ellipsoidal components detected in Vulpecula through TESS photometry

MaGiV-1 is a candidate triple ellipsoidal star system in Vulpecula at coordinates RA(J2000) 19:52:19.13 DEC(J2000) +23:29:59.7 classified as ELL+ELL, number 2344411 in AAVSO VSX database. Through photometry from the TESS Space Telescope, two significant periods describing the orbital times of the components were identified using the Fourier transform. The analysis led to determining P(A-BC) = 4.269d the orbital period of A-BC pair, the primary component with the secondary component described by another pair, and P(BC) = 0.610d the orbital period of B-C pair, the inner ellipsoidal system. However, it cannot be completely ruled out that the shorter period can be explained by pulsations of one of the two components (e.g. by the GDOR type).

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arXiv2022

ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations

The ExoClock project has been created with the aim of increasing the efficiency of the Ariel mission. It will achieve this by continuously monitoring and updating the ephemerides of Ariel candidates over an extended period, in order to produce a consistent catalogue of reliable and precise ephemerides. This work presents a homogenous catalogue of updated ephemerides for 450 planets, generated by the integration of $\sim$18000 data points from multiple sources. These sources include observations from ground-based telescopes (ExoClock network and ETD), mid-time values from the literature and light-curves from space telescopes (Kepler/K2 and TESS). With all the above, we manage to collect observations for half of the post-discovery years (median), with data that have a median uncertainty less than one minute. In comparison with literature, the ephemerides generated by the project are more precise and less biased. More than 40\% of the initial literature ephemerides had to be updated to reach the goals of the project, as they were either of low precision or drifting. Moreover, the integrated approach of the project enables both the monitoring of the majority of the Ariel candidates (95\%), and also the identification of missing data. The dedicated ExoClock network effectively supports this task by contributing additional observations when a gap in the data is identified. These results highlight the need for continuous monitoring to increase the observing coverage of the candidate planets. Finally, the extended observing coverage of planets allows us to detect trends (TTVs - Transit Timing Variations) for a sample of 19 planets. All products, data, and codes used in this work are open and accessible to the wider scientific community.

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arXiv2022

New Semiregular Variable Star Near The Wizard Nebula -- Evolution of the Red Giant MACOMP_V1

The red giant MaCoMP_V1 in Cepheus at coordinates RA (J2000) 22:49:05:49 and DEC (J2000) +57:52:41:6 is a semiregular variable star classified as SRS, number 2225960 in the AAVSO VSX database. Using the Fourier transform, the period P = 24.751(0.062)d was evaluated and, with the support of the ASAS-SN and ZTF surveys, a well-defined light curve was made. The analysis resulted in the fundamental physical parameters of MaCoMP_V1, such as the mass M = 4.97(0.38)M(Sun) and radius R = 40.5(6.7)R(Sun), with consistent values suggesting the characteristics of a semiregular red giant. In addition, the effective temperature Teff = 4500(135)K from the Gaia catalog and the stellar evolution based on the Schoenberg-Chandraskehar limit was estimated.

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