ATREIDES - I. Embarking on a trek across the exo-Neptunian landscape with the TOI-421 system

Home

All issues

Volume 701 (September 2025)

A&A, 701 (2025) A190

Full HTML

Press Release

Open Access

Table 1

Properties of the TOI-421 system.

Parameter	Symbol	Value	Unit	Origin
Stellar parameters
Spectral type		G9 V		Carleo et al. (2020)
Temperature	T_eff	5291±64	K	Krenn et al. (2024)
Surface gravity	logg	4.48±0.03		Krenn et al. (2024)
Radius	R_⋆	0.866±0.006	R_⊙	Krenn et al. (2024)
Mass	M_⋆	0.833 $\overset{+ 0.048}{_{- 0.054}}$ $\stackrel{+0.048}{_{-0.054}}$	M_⊙	Krenn et al. (2024)
Spin inclination	$i_{⋆}^{N}$ $i_{\star \rm}^\mathrm{N}$	$46.9 \overset{+ 4.2}{_{- 4.5}}$ $46.9$\stackrel{+4.2}{_{-4.5}}$$	deg	This work
	$i_{⋆}^{S}$ $i_{\star \rm}^\mathrm{S}$	133.1 $\overset{+ 4.5}{_{- 4.2}}$ $\stackrel{+4.5}{_{-4.2}}$	deg	This work
Equatorial period	P_eq	19.8±0.8	d	This work
Projected velocity	v_eq sin i_⋆	1.60±0.09	km s^-1	This work
Age	τ	${10.9}_{- 5.2}^{+ 2.9}$ $10.9$^{+2.9}_{-5.2}$$	Gyr	Krenn et al. (2024)
Limb-darkening coefficients	u₁	0.48±0.02		Krenn et al. (2024)
	u₂	0.18±0.02		Krenn et al. (2024)

Planet b parameters

Orbital period	P	5.197576±0.000005	d	Krenn et al. (2024)
Transit epoch	T₀	2459189.7341±0.0005	BJD_TDB	Krenn et al. (2024)
Eccentricity	e	0.13±0.05		Krenn et al. (2024)
Argument of periastron	ω	140±30	deg	Krenn et al. (2024)
Stellar reflex velocity	K	2.83±0.18	m s^-1	Krenn et al. (2024)
Planet mass	M_p	6.7±0.6	M_⊕	Krenn et al. (2024)
Scaled separation Orbital inclination	a/R_⋆ i	13.76 $_{- 0.22}^{+ 0.23}$ $_{-0.22}^{+0.23}$ 85.67 $_{- 0.21}^{+ 0.30}$ $^{+0.30}_{-0.21}$	deg	Krenn et al. (2024) Krenn et al. (2024)
Impact parameter	b	0.942±0..011		Krenn et al. (2024)
Transit duration	T₁₄	1.090±0.034	h	Krenn et al. (2024)
Planet-to-star radius ratio	R_p/R_⋆	0.0279±0.0008		Krenn et al. (2024)
Planet radius	R_p	2.64±0.08	R_⊕	Krenn et al. (2024)
Projected spin–orbit angle	λ_b	-35 $\overset{+ 26}{_{- 23}}$ $\stackrel{+26}{_{-23}}$	deg	This work
3D spin–orbit angle	ψ_b^N	54 $\overset{+ 12}{_{- 16}}$ $\stackrel{+12}{_{-16}}$	deg	This work
	$ψ_{b}^{S}$ $\psi^{\rm S}_\mathrm{b}$	$61 \overset{+ 11}{_{- 14}}$ $61$\stackrel{+11}{_{-14}}$$	deg
	ψ_b	$57 \overset{+ 11}{_{- 15}}$ $57$\stackrel{+11}{_{-15}}$$	deg

Planet c parameters

Orbital period	P	16.067541±0.000004	d	Krenn et al. (2024)
Transit epoch	T₀	2459195.30741±0.00018	BJD_TDB	Krenn et al. (2024)
Eccentricity	e	0.19±0.04		Krenn et al. (2024)
Argument of periastron	ω	102±14	deg	Krenn et al. (2024)
Stellar reflex velocity	K	4.1±0.3	m s^-1	Krenn et al. (2024)
Planet mass	M_p	14.1±1.4	M_⊕	Krenn et al. (2024)
Scaled separation	a/R_⋆	29.0546178±0.40		Krenn et al. (2024)
Orbital inclination	i	88.30±0.05	deg	Krenn et al. (2024)
Impact parameter	b	0.70±0.03		Krenn et al. (2024)
Transit duration	T₁₄	2.755±0.022	h	Krenn et al. (2024)
Planet-to-star radius ratio	R_p/R_⋆	0.0540±0.0006		Krenn et al. (2024)
Planet radius	R_p	5.09±0.07	R_⊕	Krenn et al. (2024)
Projected spin–orbit angle	λ_c	14.0±1.8	deg	This work
3D spin–orbit angle	$ψ_{c}^{N}$ $\psi^{\rm N}_\mathrm{c}$	44.5 $\overset{+ 4.8}{_{- 4.4}}$ $\stackrel{+4.8}{_{-4.4}}$	deg	This work
	$ψ_{c}^{S}$ $\psi^{\rm S}_\mathrm{c}$	$45.3 \overset{+ 4.7}{_{- 4.4}}$ $45.3$\stackrel{+4.7}{_{-4.4}}$$	deg
	ψ_c	44.9 $\overset{+ 4.4}{_{- 4.1}}$ $\stackrel{+4.4}{_{-4.1}}$	deg

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.