2025A&A...695A.281B

Query : 2025A&A...695A.281B

2025A&A...695A.281B - Astronomy and Astrophysics, volume 695A281 (2025/3-1)

TOI-2015 b: A sub-Neptune in strong gravitational interaction with an outer non-transiting planet.

BARKAOUI K., KORTH J., GAIDOS E., AGOL E., PARVIAINEN H., POZUELOS F.J., PALLE E., NARITA N., GRIMM S., BRADY M., BEAN J.L., MORELLO G., RACKHAM B.V., BURGASSER A.J., VAN GROOTEL V., ROJAS-AYALA B., SEIFAHRT A., MARFIL E., PASSEGGER V.M., STALPORT M., GILLON M., COLLINS K.A., SHPORER A., GIACALONE S., YALCINKAYA S., DUCROT E., TIMMERMANS M., TRIAUD A.H.M.J., DE WIT J., SOUBKIOU A., WATKINS C.N., AGANZE C., ALONSO R., AMADO P.J., BASANT R., BASTURK O., BENKHALDOUN Z., BURDANOV A., CALATAYUD-BORRAS Y., CHOUQAR J., CONTI D.M., COLLINS K.I., DAVOUDI F., DELREZ L., DRESSING C.D., DE LEON J., DEVORA-PAJARES M., DEMORY B.O., DRANSFIELD G., ESPARZA-BORGES E., FERNANDEZ-RODRIGUEZ G., FUKUDA I., FUKUI A., GALLARDO P.P.M., GARCIA L., GARCIA N.A., GHACHOUI M., GERALDIA-GONZALEZ S., GOMEZ MAQUEO CHEW Y., GONZALEZ-RODRIGUEZ J., GUNTHER M.N., HAYASHI Y., HORNE K., HOOTON M.J., HSU C.C., IKUTA K., ISOGAI K., JEHIN E., JENKINS J.M., KAWAUCHI K., KAGETANI T., KAWAI Y., KASPER D., KIELKOPF J.F., KLAGYIVIK P., LACEDELLI G., LATHAM D.W., LIBOTTE F., LUQUE R., LIVINGSTON J.H., MANCINI L., MASSEY B., MORI M., MUNOZ TORRES S., MURGAS F., NIRAULA P., ORELL-MIQUEL J., RAPETTI D., REBOLO-LOPEZ R., RICKER G., PAPINI R., PEDERSEN P.P., PELAEZ-TORRES A., PEREZ-PRIETO J.A., POULTOURTZIDIS E., RODRIGUEZ P.M., QUELOZ D., SAVEL A.B., SCHANCHE N., SANCHEZ-BENAVENTE M., SIBBALD L., SEFAKO R., SOHY S., SOTA A., SCHWARZ R.P., SEAGER S., SEBASTIAN D., SOUTHWORTH J., STANGRET M., STEFANSSON G., STURMER J., SRDOC G., THOMPSON S.J., TERADA Y., VANDERSPEK R., WANG G., WATANABE N., WILKIN F.P., WINN J., WELLS R.D., ZIEGLER C. and ZUNIGA-FERNANDEZ S.

Abstract (from CDS):

TOI-2015 is a known exoplanetary system around an M4 dwarf star, consisting of a transiting sub-Neptune planet in a 3.35-day orbital period, TOI-2015 b, accompanied by a non-transiting companion, TOI-2015 c. High-precision radial-velocity measurements were taken with the MAROON-X spectrograph, and high-precision photometric data were collected, primarily using the SPECULOOS, MUSCAT, TRAPPIST and LCOGT networks. We collected 63 transit light curves and 49 different transit epochs for TOI-2015 b. We recharacterized the target star by combining optical spectra obtained by the MAROON-X, Shane/KAST and IRTF/SpeX spectrographs, Bayesian model averaging (BMA) and spectral energy distribution (SED) analysis. The TOI-2015 host star is a K = 10.3 mag M4-type dwarf with a subsolar metallicity of [Fe/H] = -0.31 ± 0.16, and an effective temperature of Teff ≈ 3200 K. Our photodynamical analysis of the system strongly favors the 5:3 mean-motion resonance and in this scenario the planet b (TOI-2015 b) has an orbital period of Pb = 3.34 days, a mass of $\[M_{p}=9.02_{-0.36}^{+0.32} M_{\oplus}\]$, and a radius of $\[R_{p}=3.309_{-0.011}^{+0.013} R_{\oplus}\]$, resulting in a density of ρp = 0.25 ± 0.01 ρ⊕ = 1.40 ± 0.06 g cm–3; this is indicative of a Neptune-like composition. Its transits exhibit large (> 1 hr) timing variations characteristic of an outer perturber in the system. We performed a global analysis of the high-resolution radial-velocity measurements, the photometric data, and the TTVs, and inferred that TOI-2015 hosts a second planet, TOI-2015 c, in a non-transiting configuration. Our analysis places it near a 5:3 resonance with an orbital period of Pc = 5.583 days and a mass of $\[M_{p}=8.91_{-0.40}^{+0.38} M_{\oplus}\]$. The dynamical configuration of TOI-2015 b and TOI-2015 c can be used to constrain the system's planetary formation and migration history. Based on the mass-radius composition models, TOI-2015 b is a water-rich or rocky planet with a hydrogen-helium envelope. Moreover, TOI-2015 b has a high transmission-spectroscopic metric (TSM=149), making it a favorable target for future transmission spectroscopic observations with the JWST to constrain the atmospheric composition of the planet. Such observations would also help to break the degeneracies in theoretical models of the planet's interior structure.

Abstract Copyright: © The Authors 2025

Journal keyword(s): planets and satellites: detection - planets and satellites: formation - stars: individual: TOI-2015

VizieR on-line data: <Available at CDS (J/A+A/695/A281): lc.dat>

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 Ross 47 BY* 05 42 09.2676872099 +12 29 21.604835564 14.264 13.130 11.509 10.298 8.709 M4V 304 0
2 HD 104385 ** 12 01 12.79905 -40 33 09.6308   10.368 9.799 9.834   G2/3V 10 0
3 BD+25 2534 HS* 12 37 23.5161671712 +25 03 59.867922240 9.117 10.26 10.59 10.642 10.809 sdB1(k) 268 0
4 UCAC4 587-051670 PM* 15 28 30.6419042911 +27 21 13.077429289   14.191 13.576 13.410   ~ 2 0
5 UCAC4 587-051671 * 15 28 31.4793074007 +27 21 03.954132974           ~ 2 0
6 TOI-2015 PM* 15 28 31.9021082967 +27 21 38.873849132   17.134   15.161   M4 12 0
7 TOI-2015b Pl 15 28 31.9021082967 +27 21 38.873849132           ~ 5 0
8 TOI-2015c Pl 15 28 31.9021082967 +27 21 38.873849132           ~ 1 0
9 * tau08 Ser ** 15 44 42.1322923968 +17 15 51.199107660   6.140 6.136     A0V 52 0
10 NAME Barnard's star BY* 17 57 48.4984700685 +04 41 36.113879676 12.497 11.24 9.511 8.298 6.741 M4V 907 2
11 TRAPPIST-1 LM* 23 06 29.3684948589 -05 02 29.037301866     18.798 16.466 14.024 M7.5e 1306 0

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