View source for NGC 381

{{short description|Open cluster in the constellation Cassiopeia}}
{{Use dmy dates|date=September 2021}}
{{Infobox open cluster
 | image     = NGC 381 PanS.jpg
 | caption   = 
 | credit    = 
 | name      = [[New General Catalogue|NGC]] 381
 | epoch     = [[J2000]]
 | ra        = {{RA|01|08|19.9}}<ref name=Ann2002/>
 | dec       = {{DEC|+61|35|02}}<ref name=Ann2002/>
 | dist_ly   = {{Convert|957|±|93|pc|ly|order=flip|abbr=on|lk=on}}<ref name=Jayanand2018/>
 | dist_pc   = 
 | appmag_v  = 9.3<ref name=Finlay2014/>
 | size_v    = {{Val|6|ul=arcminute}}<ref name=Ann2002/> or {{Val|7|u=arcminute}}<ref name=Finlay2014/>
 | radius_ly = {{Convert|4.7|pc|ly|disp=out|abbr=on|lk=off}}<ref name=Piskunov2008/>
 | mass_msol = {{Val|32.4|45.2|18.9}}<ref name=Joshi2016/>
 | age       = {{Val|316|39|34}}<ref name=Jayanand2018/>
 | constellation = [[Cassiopeia (constellation)|Cassiopeia]]<ref name=Finlay2014/>
 | notes     = 
 | names     = [[Collinder catalogue|Collinder]] 10<ref name="simbad" />
}}

'''NGC 381''' is an [[open cluster]] of stars in the northern [[constellation]] of [[Cassiopeia (constellation)|Cassiopeia]], located at a distance of approximately {{Convert|957|pc|ly|disp=out|abbr=off|lk=on}} from the [[Sun]].<ref name=Jayanand2018/> Credit for the discovery of this cluster was given to [[Caroline Herschel]] by her brother [[William Herschel|William]] in 1787, although she may never have actually seen it.<ref name=Hoskin2006/>

This is a [[Trumpler class]] {{nowrap|III 1 m}} cluster of intermediate age,<ref name=Ann2002/> estimated at 316&nbsp;million years. This class indicates the cluster is relatively weakly concentrated, with a small brightness range and an intermediate richness of stars. A total of 350 probable members have been identified, down to 20th magnitude,<ref name=Jayanand2018/> and the cluster contains about 32 times the [[mass of the Sun]].<ref name=Joshi2016/> The cluster has a core angular radius of {{Val|2.99|0.93|u=arcminute}} and an outer cluster radius of {{Val|5.6|0.1|u=arcminute}}.<ref name=Jayanand2018/> It has a physical [[tidal radius]] of {{Convert|4.7|pc|ly|order=flip|abbr=on|lk=off}}.<ref name=Piskunov2008/> No [[giant star]]s have been discovered in this cluster.<ref name=Ann2002/> Four candidate [[variable star]]s have been found in the field of NGC 381; one of which is a suspected cluster member.<ref name=Hu2007/> The [[eclipsing binary]] OX Cassiopeiae was once thought to be a member, but is now known to be a background star system.<ref name=Crinklaw1989/>

==References==
<references>
<ref name="simbad">{{cite simbad
 | title=NGC 381
 | access-date=2006-12-22 }}</ref>

<ref name=Finlay2014>{{cite book
 | title=Concise Catalog of Deep-Sky Objects
 | first=Warren H. | last=Finlay | series=The Patrick Moore Practical Astronomy Series | page=155
 | publisher=Springer | year=2014 | edition=Second
 | isbn=978-3-319-03169-9
 | doi=10.1007/978-3-319-03170-5 }}</ref>

<ref name=Ann2002>{{cite journal
 | title=BOAO Photometric Survey of Galactic Open Clusters. II. Physical Parameters of 12 Open Clusters
 | display-authors=1 | last1=Ann | first1=H. B.
 | last2=Lee | first2=S. H. | last3=Sung | first3=H.
 | last4=Lee | first4=M. G. | last5=Kim | first5=S. -L.
 | last6=Chun | first6=M. -Y. | last7=Jeon | first7=Y. -B.
 | last8=Park | first8=B. -G. | last9=Yuk | first9=I. -S.
 | journal=The Astronomical Journal
 | volume=123 | issue=2 | pages=905–914 | date=February 2002
 | doi=10.1086/338309 | arxiv=astro-ph/0203028
 | bibcode=2002AJ....123..905A | s2cid=15064411 }}</ref>

<ref name=Jayanand2018>{{cite journal
 | first1=Jayanand | last1=Maurya | first2=Yogesh Chandra | last2=Joshi
 | title=Photometric study of the open cluster NGC 381
 | journal=Bulletin de la Société Royale des Sciences de Liège
 | volume=88 | date=October 2018 | pages=291–294
 | doi=10.25518/0037-9565.9003 | doi-access=free }}</ref>

<ref name=Hu2007>{{cite conference
 | title=Search for Exoplanets and Variables in the Open Cluster NGC 381
 | last1=Hu | first1=J. -H. | last2=Ip | first2=W. -H.
 | conference=Binary Stars as Critical Tools and Tests in Contemporary Astrophysics, International Astronomical Union. Symposium no. 240, held 22–25 August 2006 in Prague, Czech Republic, S240
 | page=333 | date=August 2007
 | bibcode=2007IAUS..240..333H }}</ref>

<ref name=Crinklaw1989>{{cite journal
 | title=A Photometric Analysis of the Eclipsing Binary OX Cassiopeiae
 | last1=Crinklaw | first1=Greg | last2=Etzel | first2=Paul B.
 | journal=Astronomical Journal
 | volume=98 | page=1418 | date=October 1989
 | doi=10.1086/115228 | bibcode=1989AJ.....98.1418C | doi-access=free }}</ref>

<ref name=Hoskin2006>{{cite journal
 | title=Caroline Herschel's catalogue of nebulae
 | last=Hoskin | first=Michael
 | journal=Journal for the History of Astronomy
 | volume=37 | pages=251–255 | date=August 2006
 | issue=3 | doi=10.1177/002182860603700301 | bibcode=2006JHA....37..251H | s2cid=115235207 }}</ref>

<ref name=Piskunov2008>{{cite journal
 | last1=Piskunov | first1=A. E. | last2=Schilbach | first2=E.
 | last3=Kharchenko | first3=N. V. | last4=Röser | first4=S.
 | last5=Scholz | first5=R.-D. | display-authors=1
 | title=Tidal radii and masses of open clusters
 | journal=Astronomy and Astrophysics
 | volume=477 | issue=1 | pages=165–172
 | date=January 2008 | doi=10.1051/0004-6361:20078525
 | bibcode=2008A&A...477..165P | doi-access=free }}</ref>

<ref name=Joshi2016>{{cite journal
 | title=Study of open clusters within 1.8 kpc and understanding the Galactic structure
 | last1=Joshi | first1=Y. C. | last2=Dambis | first2=A. K.
 | last3=Pandey | first3=A. K. | last4=Joshi | first4=S.
 | display-authors=1 | journal=Astronomy & Astrophysics
 | volume=593 | id=A116 | pages=13 | date=October 2016
 | doi=10.1051/0004-6361/201628944 | bibcode=2016A&A...593A.116J
 | arxiv=1606.06425 | s2cid=118610932 }}</ref>
</references>

==External links==
* {{WikiSky}}
* [http://messier.seds.org/xtra/ngc/n0381.html SEDS] – NGC 381

{{Sky|01|08|19.9|+|61|35|02|3744}}
{{Ngc5}}
{{Cassiopeia (constellation)}}

{{DEFAULTSORT:NGC 0381}}
[[Category:Open clusters|NGC 0381]]
[[Category:Cassiopeia (constellation)|NGC 0381]]
[[Category:NGC objects|0381]]
[[Category:Astronomical objects discovered in 1787|17871103]]