1SWASP J093010.78+533859.5 (abbreviated as J093010), also known asV441 Ursae Majoris andV442 Ursae Majoris is a quintuplestar system located in the constellationUrsa Major.[5][7] The star system is located approximately 250 light-years from Earth,[7] and was discovered using data from the "Super Wide Angle Search for Planets" (SuperWASP) project in theCanary Islands.
1SWASP J093010.78+533859.5 consists of two pairs of stars, designated J093010A and J093010B respectively, as well as a fifth star. The first pair of stars, J093010A, is a detachedeclipsing binary (anAlgol variable). The two stars within J093010A orbit with aperiod of about 1.3 days and are separated by about 5.8solar radii.[7] The second pair of stars, J093010B is aW Ursae Majoris variable; in this pair the two stars are so close as to be touching each other. The two stars within J093010B take about 5.5 hours (0.2277 days) to orbit each other.[6]
The two pairs J093010A and J093010B are separated by about 1.89arcseconds, so the separation between the two pairs is likely about 130astronomical units. The fifth star was detected based on stationaryspectral lines coming from the direction of 1SWASP J093010.78+533859.5. The fifth star likely orbits J093010A at a further distance than the eclipsing binary.[5]
J093010A is a detached (Algol-type)eclipsing binary. Its magnitude drops from a maximum of 9.44 to a primary minimum of 9.75 and a secondary minimum of 9.58 every 1.31 days. It has been given thevariable star designation V441 Ursae Majoris.[11]
J093010B is a contact (W UMa-type) eclipsing binary. Its magnitude drops by 0.28 magnitudes at the primary eclipse and 0.25 magnitudes during the secondary eclipse from a maximum magnitude of 10.55. The period is 0.23 days. It has been given the variable star designation V442 Ursae Majoris.[11]
Alight curve for V441 Ursae Majoris (J093010A), adapted from Lohret al. (2015).[7] The maximum brightness is the combined light of all 5 stars.
A light curve for V442 Ursae Majoris (J093010B), adapted from Lohret al. (2015).[7] The maximum brightness is the combined light of all 5 stars.
^Simbad assigns the 1SWASP J093010.78+533859.5 designation to component B, but various sources make clear it applies to the whole "system" of four or five stars.[7][5] Similarly, the designation 1SWASP J093012.84+533859.6 is also given to component B, but actually applies to an 18th-magnitude star 18" away.[7]
^abcdeKoo, Jae-Rim; Lee, Jae Woo; Lee, Byeong-Cheol; Kim, Seung-Lee; Lee, Chung-Uk; Hong, Kyeongsoo; Lee, Dong-Joo; Rey, Soo-Chang (2014). "1SWASP J093010.78+533859.5: A Possible Hierarchical Quintuple System".The Astronomical Journal.147 (5): 104.arXiv:1402.4575.Bibcode:2014AJ....147..104K.doi:10.1088/0004-6256/147/5/104.
^abcGazeas, K. (July 2015). "Disentangling the Quadruple System 1SWASP J093010.78+533859.5".Living Together: Planets.496: 112.Bibcode:2015ASPC..496..112G.
^abSamus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1".Astronomy Reports.61 (1): 80.Bibcode:2017ARep...61...80S.doi:10.1134/S1063772917010085.
