Qatar-4

Qatar-4

Observation data Epoch J2000.0        Equinox J2000.0
Constellation	Andromeda [1]
Right ascension	00h 19m 26.22s [2]
Declination	+44° 01′ 39.5″ [2]
Apparent magnitude  (V)	13.60 [3]
Characteristics
Evolutionary stage	main sequence [2]
Spectral type	K1V [3]
Variable type	planetary transit
Astrometry
Proper motion (μ)	RA: 0.923±0.011 mas/yr [2] Dec.: −8.921±0.009 mas/yr [2]
Parallax (π)	3.0567±0.0158  mas [2]
Distance	1,067 ± 6  ly (327 ± 2  pc)
Details
Mass	0.856+0.029 −0.030 [4]   M☉
Radius	0.800+0.015 −0.014 [4]   R☉
Luminosity	0.481 [3]   L☉
Surface gravity (log g)	4.565+0.018 −0.020 [4]   cgs
Temperature	5174+33 −35 [4]   K
Metallicity [Fe/H]	0.095+0.076 −0.088 [4]   dex
Rotational velocity (v sin i)	7.1±0.5 [3]  km/s
Age	170±0.1 [3]   Myr
Other designations
Gaia DR3 385697172809355392, Qatar 4, UCAC3 269-3518
Database references
SIMBAD	data
Exoplanet Archive	data

Qatar-4 is a faint K-dwarf star that hosts a planet in the constellation Andromeda. With an apparent magnitude of 13.60, it is impossible to detect with the naked eye, but can be detected with a powerful telescope. Qatar-4 is currently located 1,083 light years away based on parallax.

Properties

This star is a relatively young star with an age of only 170 million years. At this age, it is still on the main sequence. Qatar-4 has 89.6% the mass of the Sun, and 84.9% the latter's radius. Despite all of this, it only has 48.1% of the Sun's luminosity, which corresponds to an effective temperature of 5,120  K . Qatar-4 has a similar metallicity to the Sun, and rotates at a rate of 7.1 km/s.

Planetary system

In 2016, the Qatar Exoplanet Survey discovered a planet around this star.

The Qatar-4 planetary system ^[4]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	5.26+0.22 −0.21  MJ	0.02861	1.80536494±9−7	0.046+0.064 −0.034	87.5±1.6 °	1.083+0.022 −0.021  RJ

Qatar-4b

Discovery [3]
Discovered by	Alsubai et al. 2019
Detection method	Transit
Orbital characteristics
Semi-major axis	0.02803 ± 0.00048 au [3]
Eccentricity	0 [3]
Orbital period (sidereal)	1.8053564 d [3]
Inclination	87.5 ± 1.6° [3]
Semi-amplitude	957±16 m/s [3]
Physical characteristics
Mean radius	1.135 ± 0.11 RJ [3]
Mass	5.36 ± 0.20 MJ [3]
Mean density	4.50 ± 1.00 g cm−3 [3]
Temperature	1385 ± 50 K [3]

Qatar-4b

Qatar-4b is a Super-Jupiter orbiting the star Qatar-4 every 1.8 days. It was discovered in 2016 by the Qatar Exoplanet Survey (QES).

This planet has a very short orbit, with only 1.8 days for it to complete an orbit around Qatar-4. The period corresponds with a separation of around 0.03  AU , which is almost 20 times closer than Mercury is to the Sun. Despite that, it has a perfectly round orbit. Since the host is an active star, Qatar-4 may be destroyed by tidal waves from the star. ^[5]

Qatar-4b has over 5 times the mass of Jupiter. Despite this, it has a radius that is only 13.5% larger than the latter's. This planet has an effective temperature of 1,385 K, which classifies as a hot Jupiter, and is denser than Jupiter, with about 4 times the density.

See also

• Qatar-1
• Qatar-2
• Qatar-3
• Qatar-5

References

1. Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi: 10.1086/132034 . Constellation record for this object at VizieR.
2. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
3. Alsubai, Khalid; Mislis, Dimitris; Tsvetanov, Zlatan I.; Latham, David W.; Bieryla, Allyson; Buchhave, Lars A.; Esquerdo, Gilbert A.; Bramich, D. M.; Pyrzas, Stylianos; Vilchez, Nicolas P. E.; Mancini, Luigi (2017-04-01). "Qatar Exoplanet Survey : Qatar-3b, Qatar-4b, and Qatar-5b". The Astronomical Journal. 153 (4): 200. arXiv: 1606.06882 . Bibcode:2017AJ....153..200A. doi: 10.3847/1538-3881/aa6340 . ISSN   0004-6256. S2CID   119214858.
4. Wang, Xian-Yu; Wang, Yong-Hao; Wang, Songhu; Wu, Zhen-Yu; Rice, Malena; Zhou, Xu; Hinse, Tobias C.; Liu, Hui-Gen; Ma, Bo; Peng, Xiyan; Zhang, Hui; Yu, Cong; Zhou, Ji-Lin; Laughlin, Gregory (2021), "Transiting Exoplanet Monitoring Project (TEMP). VI. The Homogeneous Refinement of System Parameters for 39 Transiting Hot Jupiters with 127 New Light Curves", The Astrophysical Journal Supplement Series, 255 (1): 15, arXiv: 2105.14851 , Bibcode:2021ApJS..255...15W, doi: 10.3847/1538-4365/ac0835 , S2CID   235253975
5. Hamer, Jacob H.; Schlaufman, Kevin C. (2019-11-01). "Hot Jupiters Are Destroyed by Tides While Their Host Stars Are on the Main Sequence". The Astronomical Journal. 158 (5): 190. arXiv: 1908.06998 . Bibcode:2019AJ....158..190H. doi: 10.3847/1538-3881/ab3c56 . ISSN   0004-6256. S2CID   201103951.