WASP-49

WASP-49 is a binary star system about 636 light-years (195 parsecs) away in the constellation Lepus. The two stars are separated by 443 AU.^[6] The primary is a G-type main-sequence star, with a surface temperature of 5,600 K (5,330 °C; 9,620 °F). WASP-49 is depleted of heavy elements relative to the Sun. It has a metallicity Fe/H index of –0.23, meaning it has 59% the iron level of the Sun.^[5]

WASP-49

Observation data Epoch J2000      Equinox J2000
Constellation	Lepus
Right ascension	06h 04m 21.47357s[1]
Declination	−16° 57′ 55.1087″[1]
Apparent magnitude (V)	11.35[2]
Characteristics
Spectral type	G6V[3]
Astrometry
Radial velocity (Rv)	41.81±0.38[1] km/s
Proper motion (μ)	RA: 54.671 mas/yr[1] Dec.: -19.055 mas/yr[1]
Parallax (π)	5.1315±0.0158 mas[1]
Distance	636 ± 2 ly (194.9 ± 0.6 pc)
Details
A
Mass	1.003±0.10[3] M☉
Radius	1.038±0.038[3] R☉
Luminosity	0.884[4] L☉
Surface gravity (log g)	4.5±0.1[3] cgs
Temperature	5,600±150[5] K
Metallicity [Fe/H]	−0.230±0.070[5] dex
Rotational velocity (v sin i)	0.90±0.30[5] km/s
Age	11.9+0.8 −3.2[5] Gyr
B
Mass	0.337+0.009 −0.024[6] M☉
Temperature	3454+10 −25[6] K
Other designations
WDS J06044-1658AB, TOI-479, TIC 306362738, WASP-49, TYC 5936-2086-1, 2MASS J06042146-1657550[7]
Database references
SIMBAD	A
	B
Exoplanet Archive	data

Planetary system

In 2012, one exoplanet, designated WASP-49b, was discovered around the primary star by a team led by Monika Lendl.^[8] This is a hot Jupiter with an equilibrium temperature of 1369±39 K.^[8]

In 2017, WASP-49b was found to have an extensive sodium envelope.^[3] A study in 2019 using data from the Hubble Space Telescope in near-UV found clear absorption features caused by metals, including magnesium and iron. The gaseous magnesium and iron is not gravitationally bound to the planet, but could be magnetically confined to it.^[9][10] The sodium layer around WASP-49b could be due to a tidally-heated Io-like exomoon.^[11][12] In October 2024, a 5-year study was published indicating that the sodium envelope most likely comes from a distinct body orbiting WASP-49b rather than the star or the planet, although the exact dynamics of the envelope remains to be settled.^[13][14]

The WASP-49 A planetary system^[5]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.399+0.029 −0.027 MJ	0.0379+0.0010 −0.0011	2.7817387(56)	<0.026	84.89±0.19°	1.115±0.047 RJ