HAT-P-28

Star in the constellation Andromeda

HAT-P-28
Observation data Epoch J2000 Equinox J2000
Constellation	Andromeda
Right ascension	00^h 52^m 00.1876^s^[1]
Declination	+34° 43′ 42.205″^[1]
Apparent magnitude (V)	13.03^[2]
Characteristics
Evolutionary stage	main-sequence star
Spectral type	G
Astrometry

Radial velocity (R_v)	48.06^[3] km/s
Proper motion (μ)	RA: 25.615(14) mas/yr^[1] Dec.: 2.712(11) mas/yr^[1]
Parallax (π)	2.4728 ± 0.0156 mas^[1]
Distance	1,319 ± 8 ly (404 ± 3 pc)

Orbit^[4]
Primary	HAT-P-28
Companion	HAT-P-28 B
Semi-major axis (a)	0.994±0.002" (404 AU)
Details^[5]

Mass	1.02±0.05 `M`_☉
Radius	1.10^+0.09 _−0.07 `R`_☉
Luminosity	1.13^+0.23 _−0.16^[2] `L`_☉
Surface gravity (log g)	4.36±0.06^[2] cgs
Temperature	5680±90^[2] K
Metallicity [Fe/H]	0.12±0.08^[2] dex
Rotational velocity (v sin i)	0.2^+0.5 _−0.2^[2] km/s
Age	6.1^+2.6 _−1.9^[2] Gyr

Other designations
HAT-P-28, Gaia DR2 363702817083391232, GSC 02284-00503, 2MASS J00520018+3443422^[3]
Database references
SIMBAD	data

HAT-P-28 is the primary of a binary star system about 1320 light-years away. It is a G-type main-sequence star. The star's age is older than the Sun's at 6.1^+2.6
_−1.9 billion years.^[2] HAT-P-28 is slightly enriched in heavy elements, having a 130% concentration of iron compared to the Sun. Since 2014, the binary star system is suspected to be surrounded by a debris disk with a 6.1″(2500 AU) radius.^[6]

The red dwarf stellar companion was detected in 2015 at a projected separation of 0.972″^[7] and confirmed in 2016 to be either bound or comoving.^[4]

Planetary system

In 2011 a transiting hot Jupiter planet b was detected on a nearly circular orbit. The planetary equilibrium temperature is 1384±52 K.^[2] No orbital decay was detected as in 2018, despite the close proximity of the planet to the host star.^[5]

The HAT-P-28 planetary system^[5]^[2]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.626±0.037 M_J	0.0434±0.0007	3.257215±0.000007	0.051±0.033	88.0±0.9°	1.190^+0.102 _−0.075 R_J

References

^ ^a ^b ^c ^d 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.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Buchhave, L. A.; Bakos, G. Á.; Hartman, J. D.; Torres, G.; Latham, D. W.; Andersen, J.; Kovács, G.; Noyes, R. W.; Shporer, A.; Esquerdo, G. A.; Fischer, D. A.; Johnson, J. A.; Marcy, G. W.; Howard, A. W.; Béky, B.; Sasselov, D. D.; Fűrész, G.; Quinn, S. N.; Stefanik, R. P.; Szklenár, T.; Berlind, P.; Calkins, M. L.; Lázár, J.; Papp, I.; Sári, P. (2011), "HAT-P-28b AND HAT-P-29b: TWO SUB-JUPITER MASS TRANSITING PLANETS", The Astrophysical Journal, 733 (2): 116, arXiv:1103.1813, Bibcode:2011ApJ...733..116B, doi:10.1088/0004-637X/733/2/116, S2CID 119293967
^ ^a ^b "HAT-P-28". SIMBAD. Centre de données astronomiques de Strasbourg.
^ ^a ^b Ngo, Henry; Knutson, Heather A.; Hinkley, Sasha; Bryan, Marta; Crepp, Justin R.; Batygin, Konstantin; Crossfield, Ian; Hansen, Brad; Howard, Andrew W.; Johnson, John A.; Mawet, Dimitri; Morton, Timothy D.; Muirhead, Philip S.; Wang, Ji (2016), "FRIENDS OF HOT JUPITERS. IV. STELLAR COMPANIONS BEYOND 50 au MIGHT FACILITATE GIANT PLANET FORMATION, BUT MOST ARE UNLIKELY TO CAUSE KOZAI–LIDOV MIGRATION", The Astrophysical Journal, 827 (1): 8, arXiv:1606.07102, Bibcode:2016ApJ...827....8N, doi:10.3847/0004-637X/827/1/8, S2CID 41083068
^ ^a ^b ^c Penev, Kaloyan; Bouma, L. G.; Winn, Joshua N.; Hartman, Joel D. (2018), "Empirical Tidal Dissipation in Exoplanet Hosts from Tidal Spin-up", The Astronomical Journal, 155 (4): 165, arXiv:1802.05269, Bibcode:2018AJ....155..165P, doi:10.3847/1538-3881/aaaf71, PMC 6510550, PMID 31080254, S2CID 64370118
^ Merín, Bruno; Ardila, David R.; Ribas, Álvaro; Bouy, Hervé; Bryden, Geoffrey; Stapelfeldt, Karl; Padgett, Deborah (2014), "Herschel/PACS photometry of transiting-planet host stars with candidate warm debris disks", Astronomy & Astrophysics, 569: A89, arXiv:1409.0572, Bibcode:2014A&A...569A..89M, doi:10.1051/0004-6361/201322956, S2CID 10038821
^ Wöllert, Maria; Brandner, Wolfgang (2015), "A Lucky Imaging search for stellar sources near 74 transit hosts", Astronomy & Astrophysics, 579: A129, arXiv:1506.05456, Bibcode:2015A&A...579A.129W, doi:10.1051/0004-6361/201526525, S2CID 118903879

Constellation of Andromeda

Stars

Bayer	α (Alpheratz) β (Mirach) γ (Almach) δ ε ζ η θ ι κ λ μ ν ξ (Adhil) ο π ρ σ τ υ (Titawin) φ χ ψ ω A b c υ Per (Nembus)
Flamsteed	2 3 4 5 6 7 8 9 10 11 12 13 14 (Veritate) 15 18 22 23 26 28 32 36 39 41 44 45 47 55 56 58 59 63 64 65 66 6 Per
Variable	R T U W Z RT RV RX SU SW TU TW WZ XZ AB AC AD AE AF AR BM BX CC CG CN DS DX EG ET EU FF GP GQ GX GR GY HH HN IW KK KX KZ LL LN LP LQ OP OS OU PX PY QO QR QV QX V385 V428 V439 V455 V529 V807
HR	1 40 56 78 104 122 134 178 275 282 283 289 379 410 483 687 746 748 8884 8925 8950 8962 8973 9011 9074 9075 9105
HD	16175 (Buna) 222155
Other	3XMM J004232.1+411314 ADS 48 HAT-P-6 (Sterrennacht) HAT-P-16 HAT-P-19 HAT-P-28 M31-RV KELT-1 NGC 44 NGC 82 NGC 84 NGC 91 NGC 162 NGC 464 Qatar-3 Qatar-4 PA-99-N2 WASP-1 WISE 0146+4234 WISE J0005+3737 WISE J004945.61+215120.0

Exoplanets	14 Andromedae b κ Andromedae b υ Andromedae b c d Gliese 15 Ab c HD 13931 b HD 16175 b HAT-P-6b HAT-P-32b WASP-1b WASP-33b Qatar-4b Qatar-5b

Star
clusters

NGC	206 272 752 956 7686
Other	Mayall II RBC EXT8

Nebulae

NGC	7662

Galaxies

Messier	32 110
NGC	5 11 13 19 20 21 27 39 43 48 49 51 67 68 69 70 71 72 74 76 79 80 81 83 85 86 90 93 94 96 97 108 109 112 140 149 160 169 181 183 184 214 218 226 228 229 233 243 252 258 260 262 280 304 317 389 393 404 425 431 477 512 513 523 528 529 531 536 542 605 620 668 679 687 700 703 704 705 708 709 710 712 714 717 721 732 753 759 801 812 834 891 906 910 911 912 913 920 937 980 995 996 999 1000 7640 7836
Numbered	I II III IV V VIII IX X XI XVIII XIX XXI
Other	3C 66A 3C 66B Andromeda Galaxy Arp 273 Donatiello I