31 Crateris

{{Short description|Star in the constellation Corvus}}

{{Starbox begin

| name = 31 Crateris

}}

{{Starbox image

| image = 250px

| caption = A light curve for TY Corvi, plotted from Hipparcos data{{cite web

| url=https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats

| website=Centre de Données astronomiques de Strasbourg | title=/ftp/cats/more/HIP/cdroms/cats

| publisher=Strasbourg astronomical Data Center | access-date=15 October 2022}}

}}

{{Starbox observe

| epoch = J2000.0

| equino = J2000.0

| constell = Corvus

| ra = {{RA|12|00|51.16003}}[http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+104337&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id basic query result — Object query : HD 104337]

| dec = {{DEC|-19|39|32.3350}}

| appmag_v = 5.19-5.23

}}

{{Starbox character

| variable = Eclipsing binary

| class = B1.5V + ?

| b-v =

}}

{{Starbox astrometry

| radial_v = 1.7 ± 2

| prop_mo_ra = -16.17 ± 0.41

| prop_mo_dec = 6.81 ± 0.29

| parallax = 1.03

| p_error = 0.53

| parallax_footnote =

| dist_pc =

| absmag_v =

}}

{{Starbox detail

| source =

| mass = 15.5{{citation | last1=Hohle | first1=M. M. | last2=Neuhäuser | first2=R. | last3=Schutz | first3=B. F. | title=Masses and luminosities of O- and B-type stars and red supergiants | journal=Astronomische Nachrichten | volume=331 | issue=4 | pages=349 |date=April 2010 | doi=10.1002/asna.200911355 | bibcode=2010AN....331..349H |arxiv = 1003.2335 | s2cid=111387483 }}

| radius =

| gravity =

| luminosity = 52,262

| luminosity_bolometric =

| luminosity_visual =

| temperature = 23700

| metal =

| rotation =

| rotational_velocity =

| age =

| age_gyr =

}}

{{Starbox catalog

| names = 31 Crateris, TY Corvi, HD 104337, HR 4590, HIP 58587, SAO 157042, BD−18° 3295

}}

{{Starbox reference

| Simbad = 31+Crt

}}

{{Starbox end}}

31 Crateris is a binary star system in the constellation Corvus. Varying between apparent magnitudes 5.19 and 5.23 over 1.48 days, it has the variable star designation of TY Corvi.{{cite web|url=http://www.aavso.org/vsx/index.php?view=detail.top&oid=10702 |title=TY Corvi|author =Watson, Christopher|date=4 January 2010 |work=The International Variable Star Index|publisher=American Association of Variable Star Observers|access-date=11 June 2015}} It is actually a remote system with a hot blue-white star of spectral type B1.5V and a companion about which little is known. The two stars orbit each other every 2.9631 days. The primary is possibly a blue straggler of the Hyades group.{{citation | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869–879 |date=September 2008 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 | postscript=. }} The primary is around 15.5 times as massive as the Sun and 50,000 times as luminous.

British astronomer John Flamsteed numbered the stars in an expanded constellation he termed Hydra and Crater, which included the stars of Hydra immediately below the Cup. Published in 1712, this was not followed by later astronomers. 31 Crateris ended up in the constellation Corvus after formal boundaries were set in 1922.{{cite book | last = Wagman | first = Morton | date = 2003 | title = Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others | publisher = The McDonald & Woodward Publishing Company | location = Blacksburg, Virginia | isbn = 978-0-939923-78-6 |pages=390–91}}

On 27 March 1974, the Mariner 10 mission detected emissions in the far ultraviolet. These were initially thought to be Mercury's moon before the source was shown to be 31 Crateris.{{cite book|last=Moore|first=Patrick|title=The Data Book of Astronomy|publisher=CRC Press|date=2000|pages=79|isbn=9781420033441|url=https://books.google.com/books?id=fDDpBwAAQBAJ&q=moon+mercury+%2231+Crateris%22&pg=PA79}}{{cite journal|last=Stratford|first=R.L.|date=1980|title=31 Crateris reexamined|journal=The Observatory|volume=100|pages=168 | bibcode=1980Obs...100..168S}}