TEPCat: KELT-9

This page summarises the information held within TEPCat for the transiting planetary system KELT-9. Please see here for descriptions of the quantities given below.

Discovery and basic observable quantities:
Quantity	Value	Unit
Reference of discovery paper	2017Natur.546..514G
Date of discovery paper	2017 / 6 / 6	y / m / d
Data/telescope used for discovery	KELT
Right ascension	20 31 26.35	h m s
Declination	+39 56 19.8	d m s
Right ascension (decimal)	307.85979	degrees
Declination (decimal)	39.93883	degrees
V-band apparent magnitude	7.56	mag
K-band apparent magnitude	7.48	mag
Transit duration	0.16552 ( 3.9725 )	day hour
Transit depth	0.68	%
Time of mid-transit	2458162.09128 ± 0.00009	HJD or BJD
Orbital period	1.48111916 ± 0.00000013	days
Reference for orbital ephemeris	2023A+A...669A.124H

Physical properties from the most recent detailed study:
Quantity	Value	Unit
Stellar effective temperature	9329 ± 118	K
Stellar metal abundance ([Fe/H] or [M/H])	+0.14 ± 0.30	dex
Stellar mass	2.26 ± 0.03	Msun
Stellar radius	2.28 ± 0.03	Rsun
Stellar logarithmic surface gravity	4.037 +0.038 −0.040	c.g.s.
Stellar mean density	0.164 ± 0.018 ( 0.231 ± 0.025 )	ρsun g cm^-3
Orbital eccentricity	0.0 +0.035 −0.0
Orbital semimajor axis	0.03368 ± 0.00078	AU
Planetary mass	2.22 ± 0.58 ( 705 ± 184 )	Mjup Mearth
Planetary radius	1.82 ± 0.03 ( 20.40 ± 0.34 )	Rjup Rearth
Planetary surface gravity	19.0 +2.5 −2.4 3.28 +0.05 −0.06	m/s2 log(cgs)
Planetary mean density	0.370 +0.054 −0.050 ( 0.491 +0.072 −0.066 )	ρjup g cm^-3
Planetary equilibrium temperature	3921 +182 −174	K
Reference of detailed study	arXiv:2601.20849

Entries in the catalogue of orbital obliquity measurements:
Reference	λ (degrees)
Gaudi et al. (2017)	−84.8 ± 1.4
Borsa et al. (2019)	−85.78 ± 0.46
Wyttenbach et al. (2020)	−85.01 ± 0.23
Ahlers et al. (2020)	−88 ± 15
Stephen et al. (2022)	−84.8 ± 0.3

Page generated on 2026/01/29 John Southworth (Keele University, UK)