Omicron Herculis

{{Short description|Variable star in the constellation Hercules}}

{{Starbox begin

| name = o Herculis

}}

{{Starbox image

| image=

{{Location mark

|image=Hercules constellation map.svg|alt=|float=center|width=260

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=o Herculis

|x=328|y=576

}}

|caption=Location of o Herculis (circled)

}}

{{Starbox observe

| epoch = J2000

| ra = {{RA|18|07|32.55073}}

| dec = {{DEC|+28|45|44.9679}}

| appmag_v = 3.83

| constell = Hercules

}}

{{Starbox character

| class = B9.5III

| r-i =

| v-r =

| b-v = −0.02

| u-b = −0.07

| variable = γ Cas

}}

{{Starbox astrometry

| radial_v = −29.5

| prop_mo_ra = −0.02

| prop_mo_dec = +8.55

| parallax = 9.65

| p_error = 0.16

| parallax_footnote =

| absmag_v = −1.24

}}

{{Starbox detail

| source =

| mass = {{Val|3.49|0.04}}

| radius = 6.3

| luminosity = 355

| temperature = 9,484

| metal_fe = −0.06

| gravity = 2.86

| rotational_velocity = 194

| age_gyr =

}}

{{Starbox catalog

| names = o Her, 103 Herculis, BD+28 2925, FK5 681, HD 166014, HIP 88794, HR 6779, SAO 85750

}}

{{Starbox reference

|Simbad=omi+Her

}}

Omicron Herculis, Latinized from o Herculis, is a star in the constellation Hercules. It used to be called Masym ("the wrist"), but this name was transferred to Lambda Herculis.

Properties

Omicron Herculis is a B9.5III star approximately 106 pc from the Earth. It has an apparent magnitude of 3.83. The star radiates with a bluish-white hue, and has a luminosity approximately 355 times as bright as the Sun. Omicron Herculis is 3.49 solar masses. Stellar evolutionary caclulations show that it has just left the main sequence.

Omicron Herculis is an eruptive variable of the Gamma Cassiopeiae class, which are rapidly rotating B-class stars with mass outflow. It has a projected rotational velocity of 194 km/s.

Some sources list Omicron Herculis as being both spectroscopic and an interferometric binary star with a separation of about 60 milliarcseconds, although the companion star has not been confirmed.

Omicron Hercules is notable for residing close to the coordinates of the solar apex, the direction towards which the Sun is moving. This was first noticed by William Herschel in 1783, although in his first calculation he identified this point with Lambda Herculis. It will eventually become the brightest star in the night sky in approximately 3.47 million years from today, at –0.63, slightly less bright than Canopus today.

References

{{reflist|refs=

{{cite web

|title=Omicron Herculis

|first=Jim|last=Kaler

|url=http://stars.astro.illinois.edu/sow/omiher.html

|access-date=2016-05-13}}

{{cite journal|last=Tomkin|first=Jocelyn|date=April 1998|title=Once and Future Celestial Kings|journal=Sky and Telescope|volume=95|issue=4|pages=59–63|bibcode=1998S&T....95d..59T}} – based on computations from HIPPARCOS data. (The calculations exclude stars whose distance or proper motion is uncertain.) [ftp://tlgleonid.asuscomm.com/HITACHI/BOOK_ASTRO/S&T/SkyandTelescope_1998%20-%20astronomy/04/199804059063.pdf PDF]{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}}

{{cite journal |jstor=106492 |last1=Herschel |first1=William |author-link=William Herschel |date=1783 |title=On the Proper Motion of the Sun and Solar System; With an Account of Several Changes That Have Happened among the Fixed Stars since the Time of Mr. Flamstead [sic] |journal=Philosophical Transactions of the Royal Society of London |volume=73 |pages=247–83 |doi=10.1098/rstl.1783.0017 |s2cid=186213288 }}

{{cite journal | title=Surveying the Bright Stars by Optical Interferometry. III. A Magnitude-limited Multiplicity Survey of Classical Be Stars | year=2021 | last1=Hutter | first1=D. J. | last2=Tycner | first2=C. | last3=Zavala | first3=R. T. | last4=Benson | first4=J. A. | last5=Hummel | first5=C. A. | last6=Zirm | first6=H. | journal=The Astrophysical Journal Supplement Series | volume=257 | issue=2 | page=69 | doi=10.3847/1538-4365/ac23cb | arxiv=2109.06839 | bibcode=2021ApJS..257...69H | s2cid=237503492 | doi-access=free }}

{{cite journal |display-authors=1 |last1=Anders |first1=F. |last2=Khalatyan |first2=A. |last3=Chiappini |first3=C. |last4=Queiroz |first4=A. B. |last5=Santiago |first5=B. X. |last6=Jordi |first6=C. |last7=Girardi |first7=L. |last8=Brown |first8=A. G. A. |last9=Matijevič |first9=G. |last10=Monari |first10=G. |last11=Cantat-Gaudin |first11=T. |last12=Weiler |first12=M. |last13=Khan |first13=S. |last14=Miglio |first14=A. |last15=Carrillo |first15=I. |last16=Romero-Gómez |first16=M. |last17=Minchev |first17=I. |last18=de Jong |first18=R. S. |last19=Antoja |first19=T. |last20=Ramos |first20=P. |last21=Steinmetz |first21=M. |last22=Enke |first22=H. |title=Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18 |journal=Astronomy & Astrophysics |date=August 2019 |volume=628 |pages=A94 |doi=10.1051/0004-6361/201935765 |issn=0004-6361 |bibcode=2019A&A...628A..94A |arxiv=1904.11302 |doi-access=free}}

{{citation |postscript=.|author=Stassun K.G.|s2cid=166227927|display-authors=etal|date=October 2019|title=The revised TESS Input Catalog and Candidate Target List|journal=The Astronomical Journal|volume=158|issue=4|page=138|arxiv=1905.10694|bibcode=2019AJ....158..138S|doi=10.3847/1538-3881/ab3467 |doi-access=free }}

{{citation | last1=van Leeuwen | first1=F. | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 |date=November 2007 | pages=653–664 | doi=10.1051/0004-6361:20078357 | bibcode=2007A&A...474..653V | arxiv=0708.1752 | s2cid=18759600 | postscript=. }}

{{citation

| last1=Slettebak | first1=A.

| title=Spectral types and rotational velocities of the brighter Be stars and A-F type shell stars

| journal=Astrophysical Journal Supplement Series

| volume=50 | pages=55 | year=1982 | postscript=.

| bibcode=1982ApJS...50...55S | doi=10.1086/190820 | doi-access=free }}

{{citation

| title=XHIP: An extended hipparcos compilation

| last1=Anderson | first1=E. | last2=Francis | first2=Ch.

| journal=Astronomy Letters

| volume=38 | issue=5 | pages=331 | year=2012

| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015

| arxiv=1108.4971 | s2cid=119257644 | postscript=. }}

{{citation

| last1=Zorec | first1=J. | last2=Royer | first2=F.

| title=Rotational velocities of A-type stars. IV. Evolution of rotational velocities

| journal=Astronomy & Astrophysics

| volume=537 | pages=A120 | year=2012

| bibcode=2012A&A...537A.120Z | doi=10.1051/0004-6361/201117691

| arxiv=1201.2052 | s2cid=55586789 | postscript=. }}

{{citation

| display-authors=1 | last1=Samus | first1=N. N.

| last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V.

| last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N.

| title=General Catalogue of Variable Stars | version=GCVS 5.1

| journal=Astronomy Reports

| year=2017 | volume=61 | issue=1 | pages=80–88

| bibcode=2017ARep...61...80S | postscript=. |doi = 10.1134/S1063772917010085 | s2cid=125853869 }}

{{citation | last=Wilson | first=Ralph Elmer | year=1953 | title=General Catalogue of Stellar Radial Velocities | journal=Carnegie Institute Washington D.C. Publication | publisher=Carnegie Institution of Washington | location=Washington | bibcode=1953GCRV..C......0W | postscript=. }}

{{citation | last1=Royer | first1=F. | last2=Zorec | first2=J. | last3=Gómez | first3=A. E. | title=Rotational velocities of A-type stars. III. Velocity distributions | journal=Astronomy and Astrophysics | volume=463 | issue=2 | pages=671–682 |date=February 2007 | doi=10.1051/0004-6361:20065224 | bibcode=2007A&A...463..671R |arxiv = astro-ph/0610785 | s2cid=18475298 | postscript=. }}

{{citation | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | year=1966 | page=99 | bibcode=1966CoLPL...4...99J | postscript=. }}

{{citation | postscript=. | first=John | last=Lankford | date=1997 | title=History of astronomy: an encyclopedia | page=[https://archive.org/details/historyofastrono00john/page/258 258] | volume=1 | series=Garland encyclopedias in the history of science | publisher=Taylor & Francis | isbn=0-8153-0322-X | url-access=registration | url=https://archive.org/details/historyofastrono00john/page/258 }}

}}

External links

http://www.alcyone.de/SIT/bsc/HR6779.html

Category:Hercules (constellation)

Herculis, Omicron

Herculis, 103

Category:B-type giants