HD 155448 is a quintuple star system consisting of 5 young B-type stars . With an apparent magnitude of 8.72,[3] it is too dim to be visible with the naked eye.
Parallax measurements from the Hipparcos spacecraft in 1997 give the system a distance of 1,976 light years with a margin of error larger than the parallax itself.[2] The New Hipparcos Reduction gives a distance of 6,272 light years, but still with a statistical margin of error larger than the parallax value.[8]Gaia parallaxes are available for the visible components. For component C, the Gaia Data Release 2 and Gaia Early Data Release 3 (EDR3) parallaxes are both negative and somewhat meaningless.[9][7] For components A, B, and D, the Gaia EDR3 parallaxes are 0.9566±0.0440mas,[5]0.8401±0.0384mas,[6] and 0.7837±0.0263mas[7] respectively, implying a distance around 4,000 light years.
Before 2011, this star was mistaken as either a Herbig Ae/Be star[10] or a post-AGB object.[11] When the system was studied in 2011, it was originally believed to contain only 4 stars (or at least more than 2 stars). In 2011, a study conducted at the European Southern Observatory in Chile concluded that the "B" star is actually a binary star, thus reclassifying it as a quintuple star system.[4] HD 155448 A, B, C, and D. Periods have been estimated at 27,000 years for Bab, 59,000 years for AB, 111,000 years for Ac, and 327,000 years for AD.[12] However, analysis in 2011 states that the stars are not gravitationally bound to each other.[4]
All of the stars are currently on the ZAMS. At present the primary star has a mass greater than 7 solar masses and an effective temperature of 25,000 K, while the companions have masses ranging from 3-6 times the mass of the Sun, and temperatures ranging from 10,000-16,000 K.
1 2 3 Perryman, M. A. C.; Lindegren, L.; Kovalevsky, J.; Hoeg, E.; Bastian, U.; Bernacca, P. L.; Crézé, M.; Donati, F.; Grenon, M.; Grewing, M.; van Leeuwen, F. (1997-07-01). "The HIPPARCOS Catalogue". Astronomy and Astrophysics. 323: L49 –L52. Bibcode:1997A&A...323L..49P. ISSN0004-6361.
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