Astronomy:HR 858
 Position of HR 858 in Fornax | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Fornax |
| Right ascension | 02h 51m 56.246s[1] |
| Declination | −30° 48′ 52.26″[1] |
| Apparent magnitude (V) | 6.382[2] |
| Characteristics | |
| Evolutionary stage | F6V[3] + M[4] |
| Spectral type | Main sequence |
| B−V color index | +0.484[5] |
| Astrometry | |
| Radial velocity (Rv) | +10.07±0.13[1] km/s |
| Proper motion (μ) | RA: 123.229±0.070[1] mas/yr Dec.: 105.788±0.151[1] mas/yr |
| Parallax (π) | 31.2565 ± 0.0700[1] mas |
| Distance | 104.3 ± 0.2 ly (31.99 ± 0.07 pc) |
| Absolute magnitude (MV) | +3.82[5] |
| Details[4] | |
| A | |
| Mass | 1.145+0.074 −0.080 M☉ |
| Radius | 1.310+0.0240 −022 R☉ |
| Luminosity | 2.348+0.069 −0.071 L☉ |
| Surface gravity (log g) | 4.19±0.10 cgs |
| Temperature | 6,201±50 K |
| Metallicity [Fe/H] | −0.14±0.08 dex |
| Rotational velocity (v sin i) | 8.3±0.5 km/s |
| Age | 2.28±1.30[6] Gyr |
| B | |
| Radius | 0.17±0.04 R☉ |
| Temperature | 2,800±300 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
HR 858 is a star with a planetary system located 104[1] light years from the Sun in the southern constellation of Fornax. It has a yellow-white hue and is visible to the naked eye but is a challenge to see with an apparent visual magnitude of 6.4.[2] The star is drifting further away with a radial velocity of 10 km/s.[1] It has an absolute magnitude of +3.82.[5]
This object is a slightly-evolved F-type main-sequence star with a stellar classification of F6V,[3] which indicates it is generating energy through core hydrogen fusion. It is roughly two[6] billion years old and is spinning with a projected rotational velocity of 8.3 km/s. The star has 1.1 times the mass of the Sun and 1.3 times the Sun's radius. It is radiating 2.3 times the luminosity of the Sun from its photosphere at an effective temperature of 6,201 K.[4]
There is a faint co-moving stellar companion, designated component B, at an angular separation of 8.4″. This corresponds to a projected separation of 270 astronomical unit|AU. It is most likely a red dwarf star.[4]
Planetary system
In May 2019, it was announced to have at least 3 exoplanets as observed by transit method of the Transiting Exoplanet Survey Satellite. All three are orbiting close to the host star and appear to be super-Earths, about twice the size of the Earth. Components 'b' and 'c' may be in a 3:5 mean motion resonance.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | — | 0.0480+0.0010 −0.0011 |
3.58599±0.00015 | < 0.30 | — | 2.085+0.068 −0.064 R⊕ |
| c | — | 0.0674+0.0014 −0.0016 |
5.97293+0.00060 −0.00053 |
< 0.19 | — | 1.939+0.069 −0.069 R⊕ |
| d | — | 0.1027+0.0022 −0.0025 |
11.2300+0.0011 −0.0010 |
< 0.28 | — | 2.164+0.086 −0.083 R⊕ |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. 5064574720469473792 Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 Høg, E. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. doi:10.1888/0333750888/2862. Bibcode: 2000A&A...355L..27H.
- ↑ 3.0 3.1 Gray, R. O. et al. (July 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 4.2 4.3 4.4 4.5 Vanderburg, Andrew et al. (2019). "TESS Spots a Compact System of Super-Earths around the Naked-Eye Star HR 858". The Astrophysical Journal 881 (1): L19. doi:10.3847/2041-8213/ab322d. Bibcode: 2019ApJ...881L..19V.
- ↑ 5.0 5.1 5.2 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 Pace, G. (March 2013). "Chromospheric activity as age indicator. An L-shaped chromospheric-activity versus age diagram". Astronomy & Astrophysics 551: 4. doi:10.1051/0004-6361/201220364. L8. Bibcode: 2013A&A...551L...8P.
- ↑ "HR 858". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HR+858.
External links
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