All articles starting with H
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HD 93963 A
HD 93963 A (TOI-1797), a G0 V star 82.3 pc away in a visual binary with the M5 dwarf HD 93963 B, hosts two TESS/CHEOPS transiting planets: a 1.04-day super-Earth and a 3.65-day sub-Neptune.
HD 94028
HD 94028 is a metal-poor, high proper motion star in the Galactic halo whose supersolar arsenic-to-germanium ratio cannot be reproduced by standard s- and r-process nucleosynthesis alone.
HD 9446
HD 9446 is a G5V star 50.35 parsecs away with two confirmed gas giants, HD 9446 b (0.7 Jupiter masses, 30-day period) and HD 9446 c (1.82 Jupiter masses, 193-day period), found by SOPHIE radial velocities in 2009.
HD 94890
HD 94890 (Iota Antliae, HIP 53502) is a K0 giant star 61.7 parsecs away with two confirmed Jupiter-mass planets, HD 94890 b and c, found by CORALIE radial velocities and announced in 2025.
HD 95086
HD 95086 is a 17-million-year-old A8V star about 86 parsecs away with the directly imaged 5-Jupiter-mass planet HD 95086 b orbiting near 56 au between two debris belts, a young Solar System analog.
HD 95089
HD 95089 is a K-type subgiant star about 137 parsecs away hosting two radial-velocity gas giants: HD 95089 b (1.26 Jupiter masses, 464.4-day orbit, discovered 2009) and HD 95089 c (about 3.45 Jupiter masses, 1785-day orbit, discovered 2016).
HD 95735
HD 95735, better known as Lalande 21185, is a red dwarf star in Ursa Major about 8.3 light-years away, the fourth closest main-sequence star system.
HD 96548
HD 96548, also cataloged as WR 40 and V385 Carinae, is a WN8h Wolf–Rayet star in Carina, the brightest of its class, surrounded by nebula RCW 58.
HD 96700
HD 96700 is a slightly metal-poor G-type main-sequence star about 83 light-years from the Sun in Hydra, hosting three super-Earth and sub-Neptune planets detected by radial velocity and announced in 2021.
HD 97048
HD 97048 is a young Herbig Ae/Be star in the Chamaeleon I dark cloud, surrounded by a flared protoplanetary disk with a planet detected by disk gas kinematics.
HD 98800
HD 98800, also cataloged as TWA 4 and TV Crateris, is a young quadruple system of four K-type stars in Crater hosting the first known polar protoplanetary disk.
HD 99109
HD 99109 (Shama) is a K-type star about 179 light-years away in Leo hosting HD 99109 b, a 0.44-Jupiter-mass gas giant in a 439.3-day, 1.11 AU radial-velocity orbit, announced in 2005.
HD 99492
HD 99492 (83 Leonis B), K2V star 18.2 pc away in a wide binary with HD 99491, hosts two Neptune-like planets: HD 99492 b (17-day period, ~25.5 Earth masses, found 2005) and HD 99492 c (95-day period, 17.9 Earth masses, confirmed 2023).
HD 99706
HD 99706 is a K-type subgiant star about 478 light-years from Earth in Canes Venatici that hosts two gas giants found by radial velocity, discovered in 2011 and 2016.
HD domain
HD domain (histidine–aspartate domain, IPR003607): a metal-dependent phosphohydrolase protein domain in bacteria, archaea, and eukaryotes, with hydrolase, oxygenase, and lyase classes and over 318,000 members.
HD DVD
HD DVD, also called High-Definition DVD, was a high-capacity optical disc format developed by Toshiba and NEC that lost the format war to Sony's Blu-ray Disc in 2008.
HD HYUNDAI
HD Hyundai is the holding company of South Korea's largest shipbuilding group, renamed from Hyundai Heavy Industries Holdings in 2022 and led by Kisun Chung.
HD Hyundai Electric
HD Hyundai Electric is a South Korean manufacturer of power equipment, including transformers and switchgear, founded in 1977 within Hyundai Heavy Industries and holding about 25 percent of the North American power transformer market.
HD Hyundai Heavy Industries
HD Hyundai Heavy Industries (HD현대중공업) is a South Korean shipbuilding and heavy-industry company in Ulsan, founded in 1972 and ranked the world's top shipyard since 1983.
HD Radio
HD Radio, also known as NRSC-5, is a digital radio broadcasting system that transmits digital audio alongside analog AM and FM stations, endorsed by the FCC in 2002.
HD-2D
HD-2D (HD2D) is Square Enix's trademarked art style blending 2D pixel art sprites with 3D environments, coined for Octopath Traveler (2018) by Acquire, and used in Triangle Strategy, Live A Live, the Dragon Quest HD-2D remakes, and Octopath Traveler II.
HD-related protein
HD-related protein: member of the histidine-aspartate (HD)-domain metalloprotein superfamily (HD-GYP, HDOD, HDIG variants), sharing one scaffold but catalyzing hydrolysis, oxygenation, or lyase reactions; many members remain hypothetical.
HD1
HD1 is a proposed high-redshift galaxy candidate at z = 13.27, identified in 2022, which would place it about 330 million years after the Big Bang.
HDAC1
HDAC1 (histone deacetylase 1, UniProt Q13547) is a 482-aa class I zinc-dependent human deacetylase in NuRD, SIN3, CoREST, and MiDAC complexes; it represses p21/p27/p57, controls DNA repair, is embryonically essential, overexpressed in many cancers, and targeted by approved HDAC inhibitors.
HDAC2
HDAC2 (histone deacetylase 2, gene ID 3066, 6q21) is a human class I zinc-dependent histone deacetylase acting in NuRD, Sin3A, CoREST, and MiDAC repressor complexes; 85% identical to HDAC1, overexpressed in cancers, implicated in memory impairment, and targeted by HDAC1/2-selective inhibitors.
HDAC3
HDAC3 (histone deacetylase 3, gene ID 8841) is a class I zinc-dependent deacetylase whose enzymatic activity is licensed by NCoR/SMRT corepressor complexes; it regulates metabolism, circadian rhythms, inflammation, and is a drug target.
HDAC4
HDAC4 (histone deacetylase 4) is a class IIa human enzyme on chromosome 2 that shuttles between nucleus and cytoplasm, represses MEF2 and Runx2 transcription, and is required for normal development.
HDAC5
HDAC5 (histone deacetylase 5, NY-CO-9) is a class IIa human deacetylase on chromosome 17q21.31, largely scaffold-like without HDAC3, regulated by phosphorylation-dependent nuclear shuttling, implicated in heart, neurons, and cancer.
HDAC6
HDAC6 (histone deacetylase 6, EC 3.5.1.98) is the predominantly cytoplasmic class IIB HDAC with two catalytic domains and a ubiquitin-binding BUZ domain; it deacetylates α-tubulin, HSP90, and cortactin, and is targeted by inhibitors such as ricolinostat in cancer, CMT, and HFpEF trials.
HDAC9
HDAC9 (histone deacetylase 9) is a human class IIa HDAC gene at 7p21.1 encoding a 1,069-aa MEF2-interacting transcriptional repressor with very weak catalytic activity; a GWAS stroke risk locus linked to large-vessel ischemic stroke and cancer.