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Mercury-manganese star

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Type of star with a prominent spectral line due to absorption from ionized mercury

Amercury-manganese star (alsoHgMn star) is a type ofchemically peculiar star with a prominentspectral line at 398.4nm, due to absorption from ionizedmercury.^[1] These stars are ofspectral type B8, B9, or A0, corresponding to surface temperatures between about 10,000 and 15,000 K, with two distinctive characteristics:

An atmospheric excess of elements likephosphorus,manganese,gallium,strontium,yttrium,zirconium,platinum andmercury.
A lack of a strong dipolemagnetic field.

Their rotation is relatively slow, and as a consequence theiratmosphere is relatively calm. It is thought, but has not been proven, that some types ofatoms sink under the force ofgravity, while others are lifted towards the exterior of the star byradiation pressure, making a heterogeneous atmosphere.^[2]

List

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The following table includes the brightest stars in this group.

Name^[3]	Bayer orFlamsteed designation	Spectral type^[3]	Apparent visual magnitude^[3]
Alpheratz	α Andromedae	B8IVmnp	2.06
Gienah Corvi	γ Corvi A	B8III	2.59
Maia	20 Tauri	B8III	3.87
	χ Lupi	B9IV	3.96
Muliphein^[4]	γ Canis Majoris	B8II	4.10
	φ Herculis^[5]	B9mnp	4.23
	π¹ Bootis	B9p	4.91
	HIP 79098^[6]	B9IVn	5.88
	ι Coronae Borealis	A0p	4.98
	κ Cancri A	B8IIImnp	5.24
	14 Sagittae^[5]	B9p	5.89
Dabih Minor^[7]	β Capricorni B	B9.5III/IV	6.10
	HD 30963	B9 III	7.23
Nath	β Tauri	B7III	1.65
	λ¹ Sculptoris A^[8]	B9.5V	6.61
	53 Aurigae A	B9 Mn	5.74

References

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^Mercury-manganese star Archived 2014-02-19 at theWayback Machine.The Internet Encyclopedia of Science, David Darling. Accessed on line August 14, 2008.
^Michaud, Georges (May 1970)."Diffusion Processes in Peculiar A Stars".Astrophysical Journal.160:641–658.Bibcode:1970ApJ...160..641M.doi:10.1086/150459.
^^a ^b ^cNames, spectral types and apparent magnitudes taken fromSIMBAD, except as noted.
^Muliphein Archived 2008-05-17 at theWayback Machine,Stars, Jim Kaler. Accessed on line August 14, 2008.
^^a ^bAdelman, S. J. (December 1988), "Elemental Abundance Analyses with Coadded DAO Spectrograms - Part Five - the Mercury-Manganese Stars Phi-Herculis 28-HERCULIS and HR:7664",Monthly Notices of the Royal Astronomical Society,235 (3): 763,Bibcode:1988MNRAS.235..763A,doi:10.1093/mnras/235.3.763.
^Paunzen, E.; Wraight, K. T.; Fossati, L.; Netopil, M.; White, G. J.; Bewsher, D. (2013), "A photometric study of chemically peculiar stars with the STEREO satellites - II. Non-magnetic chemically peculiar stars",Monthly Notices of the Royal Astronomical Society,429 (1): 119,arXiv:1211.1535,Bibcode:2013MNRAS.429..119P,doi:10.1093/mnras/sts318
^Dabih Archived 2006-08-24 at theWayback Machine,Stars, Jim Kaler. Accessed on line August 14, 2008.
^Monier, Richard; Niemczura, Ewa (2022-05-17)."A newly discovered southern HgMn star: HD 4065A".Research Notes of the AAS.6 (5): 99.Bibcode:2022RNAAS...6...99M.doi:10.3847/2515-5172/ac6f62.ISSN 2515-5172.S2CID 248883987.

Stars

List

Formation

Evolution

Classification

Early Late Main sequence O B A F G K M Subdwarf O B WR OB Subgiant Giant Blue Red Yellow Bright giant Supergiant Blue Red Yellow Hypergiant Yellow Carbon S CN CH White dwarf Chemically peculiar Am Ap/Bp CEMP HgMn He-weak Barium Lambda Boötis Lead Technetium Be Shell B[e] Helium Extreme Blue straggler
Remnants	Compact star Parker's star White dwarf Helium planet Neutron Radio-quiet Pulsar Binary X-ray Magnetar Stellar black hole X-ray binary Burster SGR
Hypothetical	Blue dwarf Black dwarf Exotic Boson Electroweak Strange Preon Planck Dark Dark-energy Quark Q Black hole star Black Hawking Quasi-star Gravastar Thorne–Żytkow object Iron Blitzar White hole

Nucleosynthesis

Structure

Properties

Star systems

Earth-centric
observations

Lists

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