HD 192310

Last updated
HD 192310
Capricornus constellation map.svg
Red circle.svg
Location of HD 192310 (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Capricornus
Right ascension 20h 15m 17.39138s [1]
Declination −27° 01 58.7116 [1]
Apparent magnitude  (V)5.73 [2]
Characteristics
Spectral type K2+ V [3]
U−B color index 0.64 [2]
B−V color index 0.88 [2]
Variable type Suspected [4]
Astrometry
Radial velocity (Rv)−54.41±0.13 [1]  km/s
Proper motion (μ)RA: 1242.763  mas/yr [1]
Dec.: 181.175  mas/yr [1]
Parallax (π)113.4872 ± 0.0516  mas [1]
Distance 28.74 ± 0.01  ly
(8.812 ± 0.004  pc)
Absolute magnitude  (MV)6.0 [5]
Details
Mass 0.78 ± 0.04 [6]   M
Radius 0.79–0.85 [7]   R
Luminosity 0.385 ± 0.007 [8]   L
Surface gravity (log g)4.38 ± 0.19 [9]   cgs
Temperature 5069 ± 49 [9]   K
Metallicity [Fe/H]-0.01 ± 0.05 [9]   dex
Rotation 47.7 ± 4.9 days [8]
Rotational velocity (v sin i)<3 [8]  km/s
Age 7.5–8.9 [5]   Gyr
Other designations
5 G. Capricorni, CD-27°14659, GCTP  4804.00, Gl  785, HD  192310, HIP  99825, HR  7722, LHS  488, LTT  8009, NSV 12933, SAO  189065
Database references
SIMBAD data
ARICNS data

HD 192310 (also known as 5 G. Capricorni or Gliese 785) is a star in the southern constellation of Capricornus. It is located in the solar neighborhood at a distance of 28.7 light-years (8.8 parsecs ), and is within the range of luminosity needed to be viewed from the Earth with the unaided eye. (According to the Bortle scale, it can be viewed from dark suburban skies.) HD 192310 is suspected of being a variable star, but this is unconfirmed.

Contents

Description

This is a K-type main sequence star with a stellar classification of K2+ V. [3] HD 192310 has about 78% of the Sun's mass [6] and, depending on the estimation method, 79% to 85% of the radius of the Sun. [7] The effective temperature of the photosphere is about 5069 K, giving it the orange-hued glow of a K-type star. [10] It is older than the Sun, with age estimates in the range 7.5–8.9 billion years. [5] The proportion of elements other than hydrogen and helium, known as the metallicity, is similar to that of the Sun. [9] It is spinning slowly, completing a rotation roughly every 48 days. [8]

The space velocity components of this star are (U, V, W) = (–69, –13, –14) km/s. It is following an orbit through the Milky Way galaxy that has an orbital eccentricity of 0.18 at a mean galactocentric distance of 8.1  kpc. [11] The star will achieve perihelion in around 82,200 years when it comes within 20.18 ly (6.188 pc) of the Sun. [12]

Planetary system

The system has a Neptune-mass planet "b", discovered in 2010. [13] A second planet "c" was found in this system in 2011 by the HARPS GTO program, along with the now-doubtful HD 85512 b and the planets of 82 G. Eridani. The uncertainty in the mass of the second planet was much higher than for the first because of the lack of coverage around the full orbit. Both planets may be similar in composition to Neptune. They are orbiting along the inner and outer edges of the habitable zone for this star. [8] [14]

A study in 2023 updated the parameters of these two planets, and identified a number of additional radial velocity signals. While most of these signals were attributed to stellar activity, one was considered a planet candidate. If real, this third planet would be a super-Earth orbiting closer to the star than the two known planets. [15] :31 However, another 2023 study did not find this candidate signal and also attributed it to stellar activity. [16] :10

The HD 192310 planetary system [16]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b ≥16.1±0.7  M🜨 0.32±0.0174.25±0.040.11±0.02
c ≥15.9±0.9  M🜨 1.21±0.02534.9+5.9
−5.1
0.06+0.05
−0.04

See also

Related Research Articles

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<span class="mw-page-title-main">HD 47536</span> Star in the constellation Canis Major

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References

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