HD 125595 is a star with a close Neptunian[6] companion in the southern constellation of Centaurus. With an apparent visual magnitude of 9.03,[2] this star is too faint to be viewed with the naked eye. It is located at a distance of 92 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +4.5 km/s.[1] The star has a high proper motion, traversing the celestial sphere and an angular rate of 0.57 arcsecond yr−1.[7]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 14h 21m 23.186s[1] |
| Declination | −40° 23′ 38.22″[1] |
| Apparent magnitude (V) | 9.03[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | K4V(k)[3] |
| Apparent magnitude (B) | 10.137[2] |
| Apparent magnitude (J) | 7.097±0.021[2] |
| Apparent magnitude (H) | 6.608±0.026[2] |
| Apparent magnitude (K) | 6.447±0.023[2] |
| B−V color index | 1.107±0.006[2] |
| Astrometry | |
| Radial velocity (Rv) | +4.48±0.45[1] km/s |
| Proper motion (μ) | RA: −561.636[1] mas/yr Dec.: −68.516[1] mas/yr |
| Parallax (π) | 35.4337 ± 0.0762 mas[1] |
| Distance | 92.0 ± 0.2 ly (28.22 ± 0.06 pc) |
| Absolute magnitude (MV) | 6.80[2] |
| Details | |
| Mass | 0.77[4] M☉ |
| Radius | 0.73+0.02 −0.03[1] R☉ |
| Luminosity | 0.241[1] L☉ |
| Surface gravity (log g) | 4.58[4] cgs |
| Temperature | 4,672[4] K |
| Metallicity [Fe/H] | 0.13[4] dex |
| Rotation | 37.2±2.0 d[5] |
| Rotational velocity (v sin i) | 1.50[6] km/s |
| Age | 8.17[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
This is an ordinary K-type main-sequence star with a stellar classification of K4V(k),[3] which indicates it is a small star that is generating energy at its core through hydrogen fusion. It is about eight[4] billion years old and is spinning with a projected rotational velocity of 1.5 km/s,[6] giving it a 37 day rotation period.[5] The star shows a moderate level of chromospherically activity due to star spots or plagues.[6] It is smaller, cooler, dimmer, and less massive than the Sun, but shows a higher atmospheric metallicity.[4]
Planetary system
editIn 2018 an exoplanet companion was announced by the HARPS program, using the radial velocity method. It is a Neptune-mass object orbiting 0.081 AU (12.1 Gm) from the host star with a period of 9.7 days.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 0.042±0.004 MJ | 0.0809±0.0014 | 9.6737±0.0039 | 0.0 | — | — |
See also
editReferences
edit- ^ a b c d e f g h i Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e f g h Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
- ^ a b 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. (2006-07-01). "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. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. ISSN 0004-6256. S2CID 119476992.
- ^ a b c d e f g Luck, R. Earle (March 2018). "Abundances in the Local Region. III. Southern F, G, and K Dwarfs". The Astronomical Journal. 155 (3): 31. Bibcode:2018AJ....155..111L. doi:10.3847/1538-3881/aaa9b5. S2CID 125765376. 111.
- ^ a b Suárez Mascareño, A.; et al. (September 2015). "Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators". Monthly Notices of the Royal Astronomical Society. 452 (3): 2745–2756. arXiv:1506.08039. Bibcode:2015MNRAS.452.2745S. doi:10.1093/mnras/stv1441. S2CID 119181646.
- ^ a b c d e f Ségransan, D.; et al. (2011). "The HARPS search for southern extra-solar planets. XXIX. Four new planets in orbit around the moderately active dwarfs HD 63765, HD 104067, HD 125595, and HIP 70849". Astronomy and Astrophysics. 535. A54. arXiv:1107.0339. Bibcode:2011A&A...535A..54S. doi:10.1051/0004-6361/200913580. S2CID 119197766.
- ^ Bakos, Gáspár Á.; et al. (July 2002). "Revised Coordinates and Proper Motions of the Stars in the Luyten Half-Second Catalog". The Astrophysical Journal Supplement Series. 141 (1): 187–193. arXiv:astro-ph/0202164. Bibcode:2002ApJS..141..187B. doi:10.1086/340115. S2CID 36667868.