HD 74438

{{short description|Quadruple star system in the constellation Ursa Major}}

{{Starbox begin}}

{{Starbox observe

| epoch = J2000.0

| constell = Vela

| ra = {{RA|08|41|46.5806}}

| dec = {{DEC|-52|03|44.996}}

| appmag_v = +7.59 {{nowrap|(8.2/8.2/9.4/9.4){{Cite journal|last=Tokovinin|first=Andrei|date=2018-03-01|title=The Updated Multiple Star Catalog|journal=The Astrophysical Journal Supplement Series|volume=235|issue=1|pages=6|doi=10.3847/1538-4365/aaa1a5|issn=0067-0049|arxiv=1712.04750|bibcode=2018ApJS..235....6T|s2cid=119047709 |doi-access=free }}}}

}}

{{Starbox character

| class = A2mA5-A8{{cite book | last1=Houk | first1=Nancy | title=Michigan catalogue of two-dimensional spectral types for the HD stars| publisher=Ann Arbor: Dept. Of Astronomy, University of Michigan | volume=2 | pages= | year=1978 | bibcode=1978mcts.book.....H }}

| b-v =

| u-b =

| variable=

}}

{{Starbox astrometry

| radial_v =

| prop_mo_ra = −17.745

| prop_mo_dec = +17.056

| parallax = 6.9075

| p_error = 0.0755

| parallax_footnote = {{Cite Gaia EDR3|5318498001679049728}}

| dist_pc =

| absmag_v =

}}

{{Starbox orbit

| reference =

| primary = AB

| name = CD

| period_unitless = {{val|2074.2|3.5|fmt=commas}} days

| eccentricity = {{val|0.458|0.015}}

| inclination = 73.2 or 106.8

| axis_unitless = {{val|5.54|0.04|ul=au}}

| k1 = {{val|12.8|0.3}}

| k2 = {{val|18.5|0.4}}

}}

{{Starbox orbit|no_heading=y

| reference =

| primary = A

| name = B

| period_unitless = {{val|20.5729|0.0003}} days

| eccentricity = {{val|0.3692|0.0001}}

| inclination = 52.5 or 127.5

| axis_unitless = {{val|0.215|0.002|ul=au}}

| k1 = {{val|45.81|0.09}}

| k2 = {{val|50.77|0.09}}

}}

{{Starbox orbit|no_heading=y

| reference =

| primary = C

| name = D

| period_unitless = {{val|4.4243|0.0001}} days

| eccentricity = {{val|0.1535|0.0003}}

| inclination = 84.0 or 96.0

| axis_unitless = {{val|0.0681|0.001|ul=au}}

| k1 = {{val|45.81|0.09}}

| k2 = {{val|50.77|0.09}}

}}

{{Starbox detail

| source =

| component1 = A

| mass = {{val|1.70|0.06}}

| radius = {{val|1.46|0.15}}

| luminosity = {{val|8.87|1.40}}

| temperature = {{val|8250|250|fmt=commas}}

| metal_fe =

| gravity =

| rotational_velocity =

| age_myr =

| component2 = B

| mass2 = {{val|1.54|0.06}}

| radius2 = {{val|1.42|0.15}}

| luminosity2 = {{val|5.72|0.95}}

| temperature2 = {{val|7500|250|fmt=commas}}

| metal_fe2 =

| gravity2 =

| rotational_velocity2 =

| age_myr2 =

}}

{{Starbox detail |no_heading=y

| source =

| component1 = C

| mass = {{val|0.96|0.14}}

| radius = {{val|0.84|0.36}}

| luminosity = {{val|0.64|0.51}}

| temperature = {{val|5625|410|fmt=commas}}

| metal_fe =

| gravity =

| rotational_velocity =

| age_myr =

| component2 = D

| mass2 = {{val|0.87|0.14}}

| radius2 = {{val|0.80|0.29}}

| luminosity2 = {{val|0.48|0.32}}

| temperature2 = {{val|5375|410|fmt=commas}}

| metal_fe2 =

| gravity2 =

| rotational_velocity2 =

| age_myr2 =

}}

{{Starbox catalog

| names = HD 74438, CD−52°2497, SAO 236190

}}

{{Starbox reference

| Simbad = HD+74438

}}

{{Starbox end}}

HD 74438 is a spectroscopic quadruple stellar system composed of a pair of double star systems approximately 425 light years from Earth, located in open cluster IC 2391.{{cite journal |last1=Platais |first1=I. |last2=Melo |first2=C. |last3=Mermilliod |first3=J.-C. |last4=Kozhurina-Platais |first4=V. |last5=Fulbright |first5=J. P. |last6=Méndez |first6=R. A. |last7=Altmann |first7=M. |last8=Sperauskas |first8=J. |title=WIYN open cluster study: XXVI. Improved kinematic membership and spectroscopy of IC 2391 |journal=Astronomy & Astrophysics |date=January 2007 |volume=461 |issue=2 |pages=509–522 |doi=10.1051/0004-6361:20065756|arxiv=astro-ph/0611584 |bibcode=2007A&A...461..509P |s2cid=17173564 |doi-access=free }} With an estimated age of {{val|43|15|7}} million years, HD 74438 is the youngest quadruple star system known.{{cite web |last1=Plait |first1=Phil |title=A weird four-star system may lead the way to catastrophic supernovae |url=https://www.syfy.com/syfy-wire/bad-astronomy-quaternary-star-hd-74438-stars-explode |website=SYFY Official Site |access-date=4 June 2022 |archive-url=https://web.archive.org/web/20220527005009/https://www.syfy.com/syfy-wire/bad-astronomy-quaternary-star-hd-74438-stars-explode |archive-date=27 May 2022 |date=26 May 2022}} The outer orbital period of the system, estimated at around 5.7 years, is also among the shortest of quadruple systems.

The HD 74438 system was confirmed to be a gravitationally bound quadruple system in 2017 from data collected in the Gaia-ESO Survey.{{cite journal |title=The Gaia-ESO Survey: double-, triple-, and quadruple-line spectroscopic binary candidates |last1=Merle |first1=T. |last2=Van Eck |first2=S. |last3=Jorissen |first3=A. |display-authors=et al. |date=2017 |journal=Astronomy & Astrophysics |volume=608 |number=A95 |pages=A95 |doi=10.1051/0004-6361/201730442|arxiv=1707.01720 |bibcode=2017A&A...608A..95M |s2cid=119502806 |doi-access=free }} In a paper published in 2022, HD 74438 was identified as a possible progenitor of a sub-Chandrasekhar Type Ia supernova.{{cite journal |last1=Merle |first1=Thibault |last2=Hamers |first2=Adrian S. |last3=Van Eck |first3=Sophie |last4=Jorissen |first4=Alain |last5=Van der Swaelmen |first5=Mathieu |last6=Pollard |first6=Karen |last7=Smiljanic |first7=Rodolfo |last8=Pourbaix |first8=Dimitri |last9=Zwitter |first9=Tomaž |last10=Traven |first10=Gregor |last11=Gilmore |first11=Gerry |last12=Randich |first12=Sofia |last13=Gonneau |first13=Anaïs |last14=Hourihane |first14=Anna |last15=Sacco |first15=Germano |last16=Worley |first16=C. Clare |title=A spectroscopic quadruple as a possible progenitor of sub-Chandrasekhar type Ia supernovae |journal=Nature Astronomy |date=12 May 2022 |volume=6 |issue=6 |pages=681–688 |doi=10.1038/s41550-022-01664-5|arxiv=2205.05045 |bibcode=2022NatAs...6..681M |s2cid=248665714 }}