HD 40307

HD 40307

Location of HD 40307 in the night sky. The star is marked within the red diamond below the word "Pictor".
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Pictor
Right ascension	05h 54m 04.2409s[1]
Declination	−60° 01′ 24.498″[1]
Apparent magnitude (V)	7.17[1]
Characteristics
Spectral type	K2.5V[1]
B−V color index	0.93[1]
Astrometry
Radial velocity (Rv)	+30.4 ± 0.2[1] km/s
Proper motion (μ)	RA: −51.76 [1] mas/yr Dec.: −60.44 [1] mas/yr
Parallax (π)	77.3261 ± 0.0170[2] mas
Distance	42.179 ± 0.009 ly (12.932 ± 0.003 pc)
Absolute magnitude (MV)	6.57±0.01[3]
Details
Mass	0.75+0.03 −0.04[4] M☉
Radius	0.716 ± 0.010[5] R☉
Luminosity (bolometric)	0.23[6] L☉
Luminosity (visual, LV)	0.20[note 1] L☉
Surface gravity (log g)	4.47 ± 0.16[6] cgs
Temperature	4977 ± 59[6] K
Metallicity [Fe/H]	−0.31 ± 0.03[6] dex
Rotation	31.8±6.7 d[7]
Rotational velocity (v sin i)	3[4] km/s
Age	1.2 (≥ 0.2)[4] Gyr
Other designations
CD−60 1303, CPD−60 508, GC 7474, GJ 2046, HIP 27887, PPM 355061, SAO 249388, 2MASS J05540421-6001245.[1]
Database references
SIMBAD	data
Exoplanet Archive	data
ARICNS	data
Extrasolar Planets Encyclopaedia	data

HD 40307 is an orange (K-type) main-sequence star located approximately 42 light-years away in the constellation of Pictor (the Easel), taking its primary name from its Henry Draper Catalogue designation. It is calculated to be slightly less massive than the Sun. HD 40307 was observed during or before 1900 as part of the Cape Photographic Durchmusterung.^[8] The star has six known planets, three discovered in 2008^[1][9] and three more in 2012. One of them, HD 40307 g, is a potential super-Earth in the habitable zone, with an orbital period of about 200 days. This object might be capable of supporting liquid water on its surface, although much more information must be acquired before its habitability can be assessed.^{[10][11][12][13]}

No stellar companions to HD 40307 were detected as in 2018.^[14]

History and nomenclature[]

The designation HD 40307 is from the Henry Draper Catalogue, which is based on spectral classifications made between 1911 and 1915 by Annie Jump Cannon and her co-workers, and was published between 1918 and 1924.^[15][16]

Characteristics[]

As a K-type star, HD 40307 emits orange-tinted light.^[1] It has only about three-quarters of the Sun's radius and mass.^[4] Its temperature is measured at slightly under 5000 K. This is relatively high for a K-type star, approaching the temperatures normally found in G-type stars such as the Sun.^[17]

The astronomers who discovered the planets orbiting HD 40307 suggested that the metallicities of stars determine whether or not the planetary bodies that orbit them will be terrestrial, like Earth, or gaseous, like Jupiter and Saturn.^[6]

Distance and visibility[]

Despite its relative proximity to the Sun at 42 light-years, HD 40307 is not visible to the naked eye, given its apparent magnitude of 7.17.^[18] It came within 6.4 light-years of the Sun about 413,000 years ago.^[19]

Planetary system[]