HD 15082

HD 15082 (also known as WASP-33) is a star located 397 light years away^[3] in the northern constellation of Andromeda.^[12] The star is a Delta Scuti variable^[13] and a planetary transit variable. A hot Jupiter type extrasolar planet, named WASP-33b or HD 15082b, orbits this star with an orbital period of 1.22 days. It is the first Delta Scuti variable known to host a planet.^[14]

HD 15082

A light curve for V807 Andromedae (HD 15082), plotted from TESS data.[1] The deep minima are caused by the planet transits.
Observation data Epoch J2000      Equinox J2000
Constellation	Andromeda[2]
Right ascension	02h 26m 51.0583s[3]
Declination	+37° 33′ 01.736″[3]
Apparent magnitude (V)	8.3[4]
Characteristics
Evolutionary stage	main sequence[3]
Spectral type	A5m[5] (kA5hA8mF4)‍[6]
B−V color index	0.27[7]
Variable type	δ Sct[4]+planetary transit
Astrometry
Radial velocity (Rv)	−9.20±2.8[8] km/s
Proper motion (μ)	RA: −0.977(35) mas/yr[3] Dec.: −8.895(34) mas/yr[3]
Parallax (π)	8.2238±0.0327 mas[3]
Distance	397 ± 2 ly (121.6 ± 0.5 pc)
Absolute magnitude (MV)	+2.85[2]
Details
Mass	1.55±0.04[9] M☉
Radius	1.51[10] R☉
Luminosity	6.6[3] L☉
Surface gravity (log g)	4.3±0.2[4] cgs
Temperature	7,400±200[4] K
Metallicity [Fe/H]	0.1±0.2[9] dex
Rotational velocity (v sin i)	86[4] km/s
Age	100[11] Myr
Other designations
V807 And, BD+36 489, HD 15082, HIP 11397, SAO 55561, WASP-33, 2MASS J02265106+3733017, Gaia DR2 328636019723252096
Database references
SIMBAD	data

Properties

HD 15082 is an Am star, which makes its stellar classification challenging to discern. The hydrogen lines and effective temperature of the star are similar to spectral type A8, however the calcium II K line resembles that of an A5 star, and the metallic lines are more similar to an F4 star. The spectral type is written kA5hA8mF4.^[9] The star is about 100^[11] million years old and is spinning with a projected rotational velocity of 86 km/s.^[4] It has 1.55^[9] times the mass of the Sun and 1.51 times the Sun's radius.^[10]

The intrinsic variability of HD 15082 was discovered in 2011 by Enrique Herrero et al.^[4] Delta Scuti variables usually exhibit many pulsation modes, and HD 15082 is no exception, with 8 measured high frequency p-modes.^[13] Another proposed non-radial mode, which could be induced by tidal interactions with the planet, would make this star also a Gamma Doradus variable.^[9] This star has the GCVS variable star designation V807 Andromedae. ^[15]

Planetary system

In 2006, the SuperWASP project announced the discovery of an extrasolar planet, designated WASP-33b, orbiting the star. The discovery was made by detecting the transit of the planet as it passes in front of its star, an event which occurs every 1.22 days.^[16]

The HD 15082 planetary system^{[9][17][note 1]}

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	< 4.59 MJ	0.02558 (± 0.00023)	1.21987089 ± 1.5×10−07	0	87.67°	1.438 RJ

Notes

1. Parameters from the photometric + radial velocity solution in table 3 of Cameron et al. (2010). Different analysis methods result in slightly different parameters, see Cameron et al. (2010) for details.