TOI-4342
Stellar characteristics
TOI-4342 is an early red dwarf with an effective temperature of 3901±69 K, corresponding to the spectral class M0V. It is a single star with stellar companions ruled out by sky surveys, speckle imaging and the radial velocity method.
Planetary system
The star hosts two planets discovered by the transit method. They were initially observed in TESS data from Sector 13 (June and July 2019) and Sector 27 (July 2020) and were validated with ground based observations with LCO telescope network during 2021, with a study published in 2023. The planets are orbiting close to a 2:1 mean-motion resonance.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 7.83+0.93 −0.88 M🜨 |
0.05251+0.00011 −0.00011 |
5.5382498+0.0000057 −0.0000058 |
~0 | 89.13+0.15 −0.13° |
2.266+0.038 −0.038 R🜨 |
| c | 8.53+0.90 −0.94 M🜨 |
0.08140+0.00017 −0.00017 |
10.688716+0.000015 −0.000015 |
~0 | 89.63+0.12 −0.12° |
2.820+0.024 −0.025 R🜨 |
Both planets are sub-Neptunes, similar in size, expected to have atmospheres with a significant fraction of hydrogen and helium. Based on the calculated insolation, the planets are expected to have equilibrium temperatures of 633.6+6.2
−6.3 K and 508.9+5.0
−5.0 K respectively.
As of January 2025, the planets' masses have not yet been directly measured, though their masses estimated based on the empirical mass–radius relationship were noted in the discovery paper to fall above the limits of detection for the radial velocity method.
Due to orbiting within 5% of the 2:1 mean-motion resonance, the system is expected to show transit-timing variations due to mutual perturbations. Observation of the amplitudes of this perturbation could additionally help constrain planet masses. However, the limited observations available by the time of the discovery paper were only adequate to rule out deviations by more than 5 min from linear ephemerides. The observed low value of perturbation also confirms a low orbital eccentricity for the planets.
See also
- TOI-270 – another M-type main sequence star with two sub-Neptunes
Notes
- ^ Masses are not directly measured, they are estimated from an empirical mass-radius relationship.
References
- ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ Tey, Evan; et al. (March 2023). "TESS Discovery of Twin Planets near 2:1 Resonance around Early M Dwarf TOI 4342". The Astronomical Journal. 165 (3) 93. arXiv:2301.01370. Bibcode:2023AJ....165...93T. doi:10.3847/1538-3881/acaf88. S2CID 255416187.
- ^ Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
- ^ Buder, Sven; Sharma, Sanjib; Kos, Janez; Amarsi, Anish M.; Nordlander, Thomas; Lind, Karin; Martell, Sarah L.; Asplund, Martin; Bland-Hawthorn, Joss; Casey, Andrew R.; De Silva, Gayandhi M. (2021). "The GALAH+ Survey: Third Data Release". Monthly Notices of the Royal Astronomical Society. 506: 150–201. arXiv:2011.02505. Bibcode:2021MNRAS.506..150B. doi:10.1093/mnras/stab1242.
- ^ "TOI-4342". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 September 2023.
