Astronomy:Rho Indi
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Indus |
| Right ascension | 22h 54m 39.482s[1] |
| Declination | –70° 04′ 25.35″[1] |
| Apparent magnitude (V) | +6.05[2] |
| Characteristics | |
| Spectral type | G1 V Fe+0.3[3] |
| U−B color index | +0.22[4] |
| B−V color index | +0.66[4] |
| Astrometry | |
| Radial velocity (Rv) | −2.29±0.12[1] km/s |
| Proper motion (μ) | RA: −43.140[1] mas/yr Dec.: +72.728[1] mas/yr |
| Parallax (π) | 37.4641 ± 0.0253[1] mas |
| Distance | 87.06 ± 0.06 ly (26.69 ± 0.02 pc) |
| Absolute magnitude (MV) | +3.90[5] |
| Details[6] | |
| Mass | 1.317±0.083 M☉ |
| Radius | 1.456±0.024 R☉ |
| Luminosity | 2.24 L☉ |
| Surface gravity (log g) | 4.23 cgs |
| Temperature | 5,849 K |
| Metallicity [Fe/H] | 0.18 dex |
| Rotation | 26.7 d[7] |
| Rotational velocity (v sin i) | 3.1 km/s |
| Age | 4.6+1.0 −0.4 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
ρ Indi, Latinised as Rho Indi (also HR 8701 or HD 216437), is a yellow-hued star in the constellation Indus. With an apparent visual magnitude of +6.05[2] it is, barely, a naked eye star, not visible in the northern hemisphere outside the tropics. Based upon an annual parallax shift of 37.46 mas, it is located 87 light-years (27 parsecs) from the Sun. The star is moving closer to the Sun with a radial velocity of −2 km/s.[1]
Properties
The stellar classification of Rho Indi is G1 V Fe+0.3,[3] which indicates it is a G-type main-sequence star with a mild overabundance of iron in its outer atmosphere. However, Houk and Cowley (1975) classified it as G2.5 IV,[8] suggesting it is instead a somewhat more evolved subgiant star. It has an estimated 1.32 times the mass of the Sun and 1.46 times the Sun's radius. The star is radiating about 2.24 times the Sun's luminosity from its photosphere at an effective temperature of 5,849 K. It is around 4.6 billion years old and is spinning with a leisurely projected rotational velocity of 3.1 km/s.[6]
Planetary system
On September 17, 2002, this star was found to have a planetary companion, designated Rho Indi b.[9] The discovery was made by measuring variations in the host star's radial velocity, thereby indicating the presence of a perturbing object. Based upon the data, the object is orbiting the host star with a period of about 3.7 years at an eccentricity of 0.32. The semimajor axis for this orbit is around 2.5 times the distance from the Earth to the Sun. Since the inclination of the orbit to the line-of-sight was initially unknown, only a lower bound on the planet's mass could be determined. It has at least 2.3 times Jupiter's mass.[9] In 2023, the inclination and true mass of Rho Indi b were determined via astrometry.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 3.88±0.73 MJ | 2.501+0.036 −0.037 |
3.658±0.034 | 0.318±0.028 | 35.0+10.0 −6.1 or 145.0+6.1 −10.0° |
— |
See also
- Tau1 Gruis, a star with a separate exoplanet discovery by the same team
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237. Bibcode: 2002yCat.2237....0D.
- ↑ 3.0 3.1 Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M.
- ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 6.0 6.1 Valenti, Jeff A.; Fischer, Debra A. (2005). "Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs". The Astrophysical Journal Supplement Series 159 (1): 141–166. doi:10.1086/430500. Bibcode: 2005ApJS..159..141V.
- ↑ Mayor, M. et al. (2004). "The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE". Astronomy and Astrophysics 415 (1): 391–402. doi:10.1051/0004-6361:20034250. Bibcode: 2004A&A...415..391M.
- ↑ Houk, N.; Cowley, A. P. (1975). Michigan catalogue of two-dimensional spectral types for the HD stars. 1. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode: 1975mcts.book.....H.
- ↑ 9.0 9.1 Jones, Hugh R. A. et al. (2002). "Extrasolar planets around HD 196050, HD 216437 and HD 160691". Monthly Notices of the Royal Astronomical Society 337 (4): 1170–1178. doi:10.1046/j.1365-8711.2002.05787.x. Bibcode: 2002MNRAS.337.1170J.
- ↑ 10.0 10.1 Xiao, Guang-Yao et al. (May 2023). "The Masses of a Sample of Radial-Velocity Exoplanets with Astrometric Measurements". Research in Astronomy and Astrophysics 23 (5): 055022. doi:10.1088/1674-4527/accb7e. Bibcode: 2023RAA....23e5022X.
Coordinates: 
22h 54m 39.4833s, −70° 04′ 25.352″
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