HD 146389
| Observation data EpochJ2000EquinoxJ2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 16h15m50.36526s[1] |
| Declination | 10° 01′ 57.2844″[1] |
| Apparent magnitude(V) | 9.447±0.024[2] |
| Characteristics | |
| Spectral type | F8[3] |
| B−Vcolor index | 0.476 |
| J−Hcolor index | 0.181 |
| J−Kcolor index | 0.289 |
| Astrometry | |
| Radial velocity(Rv) | −9.06±0.53[1]km/s |
| Proper motion(μ) | RA:−31.073[1]mas/yr Dec.:−39.171[1]mas/yr |
| Parallax(π) | 7.3115 ± 0.0429mas[1] |
| Distance | 446 ± 3ly (136.8 ± 0.8pc) |
| Details | |
| Mass | 1.203±0.036[4]M☉ |
| Radius | 1.331+0.030 −0.025[4]R☉ |
| Luminosity | 2.838±0.024[1]L☉ |
| Surface gravity(logg) | 4.25+0.012 −0.013[2]cgs |
| Temperature | 6,150±80[4]K |
| Metallicity[Fe/H] | 0.06[5]dex |
| Rotational velocity(vsini) | 8.6±0.4[2]km/s |
| Age | 350 Myr[5] 400±500[6]Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 146389(also known asWASP-38), is astarwith a yellow-white hue in the northernconstellationofHercules.The star was given the formal nameIrenaby theInternational Astronomical Unionin January 2020.[8][9]It is invisible to the naked eye with anapparent visual magnitudeof 9.4[2]The star is located at a distance of approximately 446light yearsfrom theSunbased onparallax,but is drifting closer with aradial velocityof −9 km/s.[1]The star is known to host oneexoplanet,designatedWASP-38bor formally named 'Iztok'.
The stellar classification of HD 146389 is F8,[3]which is anF-type starof uncertainluminosity class.The age of the star is uncertain. It shows a low lithium abundance, which suggests an age of more than 5 billion years. However, the rotation rate indicates an age closer to one billion.[2]The study in 2015 utilizingChandra X-ray Observatory,have failed to detect any X-ray emissions from the star during planetary eclipse, which may indicate an unusually low coronal activity or the presence of absorbing gas ring formed by atmosphere escaping planet WASP-38 b.[10]The star is 33% larger and 20% more massive than the Sun.[4]It is radiating nearly three[1]times the luminosity of the Sun at aneffective temperatureof 6,150 K.[4]
Planetary system
[edit]The "hot Jupiter" class planet WASP-38 b, later named 'Iztok', was discovered around HD 146389 in 2010.[2]The planet is losing significant amount of gas, estimated to 0.023 Earth masses per billion years.[3]In 2013, it was found the planetary orbit is surprisingly well aligned with the rotational axis of the parent star, despite the noticeable orbital eccentricity.[11][4]
A 2012 study, utilizing aRossiter–McLaughlin effect,have determined the orbital plane of WASP-38b is poorly constrained but probably aligned with the equatorial plane of the star, misalignment equal to 15+33
−43°.[12]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (Iztok) | 2.691±0.036MJ | 0.07522+0.00074 −0.00075 |
6.871815+0.000045 −0.000042 |
0.0314+0.0046 −0.0041 |
89.69+0.3 −0.25° |
1.094+0.029 −0.028RJ |
References
[edit]- ^abcdefghiBrown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData 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 sourceatVizieR.
- ^abcdefgBarros, S. C. C.; et al. (2011). "WASP-38b: A transiting exoplanet in an eccentric, 6.87d period orbit".Astronomy & Astrophysics.525:A54.arXiv:1010.0849.Bibcode:2011A&A...525A..54B.doi:10.1051/0004-6361/201015800.S2CID5723076.
- ^abcEhrenreich, D.; Désert, J.-M. (2011). "Mass-loss rates for transiting exoplanets".Astronomy & Astrophysics.529:A136.arXiv:1103.0011.Bibcode:2011A&A...529A.136E.doi:10.1051/0004-6361/201016356.S2CID119302960.
- ^abcdefBrown, D. J. A.; et al. (2012). "Analysis of Spin-Orbit Alignment in the Wasp-32, Wasp-38, and Hat-P-27/Wasp-40 Systems".The Astrophysical Journal.760(2): 139.arXiv:1303.5649.Bibcode:2012ApJ...760..139B.doi:10.1088/0004-637X/760/2/139.S2CID54033638.
- ^abDelgado Mena, E.; et al. (April 2015). "Li abundances in F stars: planets, rotation, and Galactic evolution".Astronomy & Astrophysics.576:A69.arXiv:1412.4618.Bibcode:2015A&A...576A..69D.doi:10.1051/0004-6361/201425433.S2CID56051637.A69.
- ^Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars".Astronomy and Astrophysics.575:A18.arXiv:1411.4302.Bibcode:2015A&A...575A..18B.doi:10.1051/0004-6361/201424951.S2CID54555839.
- ^"HD 146389".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved2020-01-18.
- ^"IAU Catalog of Star Names (IAU-CSN)".IAU Division CWorking Group on Star Names(WGSN). January 1, 2021.Retrieved2021-01-18.
- ^"The IAU announces names for WASP exoplanets".WASP Planets.5 January 2020.Retrieved2021-01-18.
- ^Salz, M.; et al. (2015). "High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood".Astronomy & Astrophysics.576:A42.arXiv:1502.00576.Bibcode:2015A&A...576A..42S.doi:10.1051/0004-6361/201425243.S2CID55139248.
- ^Simpson, E. K.; et al. (2011)."The spin-orbit angles of the transiting exoplanets WASP-1b, WASP-24b, WASP-38b and HAT-P-8b from Rossiter-McLaughlinobservations ".Monthly Notices of the Royal Astronomical Society.414(4): 3023–3035.arXiv:1011.5664.Bibcode:2011MNRAS.414.3023S.doi:10.1111/j.1365-2966.2011.18603.x.S2CID46522188.
- ^Albrecht, Simon; et al. (2012), "Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments",The Astrophysical Journal,757(1): 18,arXiv:1206.6105,Bibcode:2012ApJ...757...18A,doi:10.1088/0004-637X/757/1/18,S2CID17174530
