TY Coronae Borealis

{{Short description|Variable white dwarf in the constellation Corona Borealis}}

{{Starbox image

| image = 280px

| caption = A blue band light curve for TY Coronae Borealis, adapted from Bognár et al. (2019)

}}

{{Starbox observe

| epoch = J2000.0

| constell = Corona Borealis

| ra = {{RA|16|01|23.187}}

| dec = {{DEC|+36|48|34.29}}

| appmag_v = {{Val|14.435|0.018}}

}}

{{Starbox character

| type = White dwarf

| class=DA4.4

| variable = ZZ Ceti

}}

{{Starbox astrometry

| prop_mo_ra = 101.113

| prop_mo_dec = −545.353

| pm_footnote =

| parallax = 30.4668

| p_error = 0.0187

| parallax_footnote =

| absmag_v = +11.81

}}

{{Starbox detail

| mass = {{val|0.593|0.028}} to {{Val|0.615|0.024|0.025}}

| radius = {{Val|0.0131|0.0014}}

| luminosity = {{Val|1.83|0.03|e=-3}}

| gravity = 8.194

| temperature = 11,000

| age_myr = 447 (white dwarf stage)

}}

{{Starbox catalog

| names = TY CrB, Ross 808, WD 1600+369, LTT 14769, NLTT 41782, 2MASS J16012317+3648351{{cite simbad | title=TY CrB | accessdate=5 December 2016}}

}}

{{Starbox reference

| Simbad = TY+CrB

}}

TY Coronae Borealis, also known as Ross 808, is a white dwarf in the constellation Corona Borealis. It is 107 light-years distant from Earth, and has a dim apparent magnitude of 14.4.

It is a pulsating white dwarf of the DAV (ZZ Ceti) type. The variation in the blue band is of 0.14 magnitudes, over a period of 15 minutes. It was confirmed as a variable star in 1976, and now has the variable-star designation TY Coronae Borealis. Being of this variable class, it has been a target for asteroseismic analyses, in attempt to derive its physical properties such as mass, radius and gravity. However, it seems estimations of the stellar mass derived for this star using asteroseismology had been overestimated.

TY Coronae Borealis has around 0.6 times the mass of the Sun and a tiny diameter of only 1.3% that of the Sun. It is a dim star, with 0.2% of the Sun's luminosity. It has an effective temperature of about 11,000 K, have taken 450 million years to cool to its temperature. This is also its age as a white dwarf.

References

{{reflist|refs=

{{cite journal |last1=Bognár |first1=Zs. |last2=Paparó |first2=M. |last3=Sódor |first3=Á. |last4=Jenei |first4=D. I. |last5=Kalup |first5=Cs. |last6=Bertone |first6=E. |last7=Chavez-Dagostino |first7=M. |last8=Montgomery |first8=M. H. |last9=Gyõrffy |first9=Á. |last10=Molnár |first10=L. |last11=Ollé |first11=H. |last12=Pápics |first12=P. I. |last13=Plachy |first13=E. |last14=Verebélyi |first14=E. |title=Wandering near the red edge: photometric observations of three cool ZZ Ceti stars |journal=Monthly Notices of the Royal Astronomical Society |date=January 2019 |volume=482 |issue=3 |pages=4018–4031 |doi=10.1093/mnras/sty2884 |doi-access=free |arxiv=1810.09711 |bibcode=2019MNRAS.482.4018B }}

{{Cite journal |last1=Chen |first1=Y H |last2=Shu |first2=H |date=2021-02-01 |title=Asteroseismology of the DAV star R808 |journal=Monthly Notices of the Royal Astronomical Society |volume=500 |issue=4 |pages=4703–4709 |doi=10.1093/mnras/staa3572 |doi-access=free |issn=0035-8711|arxiv=2011.06918 }}

{{Cite journal |last1=Bischoff-Kim |first1=Agnès |last2=Bell |first2=Keaton J. |date=2024-07-12 |title=Constraints from Parallaxes and Average Period Spacings in the Asteroseismic Study of Eight Hydrogen-atmosphere Pulsating White Dwarfs |journal=The Astrophysical Journal |language=en |volume=970 |issue=1 |pages=27 |doi=10.3847/1538-4357/ad4edc |doi-access=free |bibcode=2024ApJ...970...27B |issn=0004-637X}}

{{cite journal|author1=McGraw, John T. |author2=Robinson, Edward L. |date=1976|title=High-speed photometry of luminosity-variable DA dwarfs: R808, GD 99, and G 117-B15A|journal=Astrophysical Journal Letters|volume=205|pages=L155-58| doi=10.1086/182112 |bibcode=1976ApJ...205L.155M}}

{{Cite journal |last1=Bédard |first1=A. |last2=Bergeron |first2=P. |last3=Fontaine |first3=G. |date=2017-10-05 |title=Measurements of Physical Parameters of White Dwarfs: A Test of the Mass–Radius Relation |journal=The Astrophysical Journal |volume=848 |issue=1 |pages=11 |doi=10.3847/1538-4357/aa8bb6 |doi-access=free |arxiv=1709.02324 |bibcode=2017ApJ...848...11B |issn=0004-637X}}

{{Cite journal |last1=Limoges |first1=M. -M. |last2=Bergeron |first2=P. |last3=Lépine |first3=S. |date=2015-08-01 |title=Physical Properties of the Current Census of Northern White Dwarfs within 40 pc of the Sun |bibcode=2015ApJS..219...19L |journal=The Astrophysical Journal Supplement Series |volume=219 |issue=2 |pages=19 |doi=10.1088/0067-0049/219/2/19 |arxiv=1505.02297 |issn=0067-0049}}

{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10631 |title=TY Coronae Borealis|author =Watson, Christopher |date=4 January 2010 |work=AAVSO Website|publisher=American Association of Variable Star Observers|accessdate=23 November 2014}}

{{Cite journal |last1=Romero |first1=A. D. |last2=Córsico |first2=A. H. |last3=Althaus |first3=L. G. |last4=Kepler |first4=S. O. |last5=Castanheira |first5=B. G. |last6=Miller Bertolami |first6=M. M. |date=2012-02-21 |title=Toward ensemble asteroseismology of ZZ Ceti stars with fully evolutionary models |journal=Monthly Notices of the Royal Astronomical Society |volume=420 |issue=2 |pages=1462–1480 |doi=10.1111/j.1365-2966.2011.20134.x |doi-access=free |arxiv=1109.6682 |bibcode=2012MNRAS.420.1462R |issn=0035-8711}}

{{Cite journal |last1=Calcaferro |first1=Leila M. |last2=Córsico |first2=Alejandro H. |last3=Uzundag |first3=Murat |last4=Althaus |first4=Leandro G. |last5=Kepler |first5=S. O. |last6=Werner |first6=Klaus |date=2024-11-01 |title=An analysis of spectroscopic, seismological, astrometric, and photometric masses of pulsating white dwarf stars |journal=Astronomy & Astrophysics |language=en |volume=691 |pages=A194 |doi=10.1051/0004-6361/202450582 |arxiv=2409.03896 |bibcode=2024A&A...691A.194C |issn=0004-6361}}

}}

Category:Corona Borealis

Category:Pulsating white dwarfs

Coronae Borealis, TY