 RGB composite color image of the shell surrounding the nova T Aurigae, made from threenarrow band images: Blue = 4800Å, green =Hα at 6563 Å and red = [NII] at 6583 Å. From Santamariaet al. 2020[1] | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Auriga |
| Right ascension | 05h 31m 59.118s[2] |
| Declination | +30° 26′ 45.03″[2] |
| Apparent magnitude (V) | 4.5Max. 15Min. |
| Astrometry | |
| Distance | 880+46 −35[3] pc |
| Characteristics | |
| Variable type | Classical Nova, Eclipsing Binary |
| Other designations | |
| Nova Aur 1891,GCRV 56251, Lan 652, SBC9 326,BD+30° 923a,HD 36294, CDS 507,HR 1841, AAVSO 0525+30, Gaia DR2 3446266197646225536 | |
| Database references | |
| SIMBAD | data |
T Aurigae (orNova Aurigae 1891) was anova, which lit up in theconstellationAuriga in 1891.Thomas David Anderson, an amateur astronomer inEdinburgh, reported that he was "almost certain" he saw the nova at 02:00 UT on 24 January 1892, when it was slightly brighter thanχ Aurigae (apparent magnitude 4.74). He mistook the star for26 Aurigae, although he noted to himself that it seemed brighter than he remembered it being. He saw it twice more during the following week. On 31 January 1892 he realized his mistake, and wrote a note toRalph Copeland (the Astronomer Royal of Scotland) reporting his discovery.[4] Professor Copeland immediately reported the discovery via telegram toWilliam Huggins, who made the first spectroscopic observations of T Aurigae on 2 February 1892, when the star was a magnitude 4.5 object.[5] T Aurigae was the first nova to be observed spectroscopically.[6]
Strope and Schaefer report that the peak brightness of T Aurigae was magnitude 4.5,.[8] Pre-discovery images onphotographic plates allowed the a light curve beginning in late 1891 to be constructed.[7]AAVSO data shows that T Aurigae's quiescent magnitude is 15.3.
In 1958 observations of the stars forming T Aurigae with theCrossley telescope showed that it is aneclipsing binary, with a period of 4.9 hours, and an eclipse depth of 0.18 magnitudes.[9] T Aurigae was the third nova that was discovered to be a short-period eclipsing binary, and that discovery led to increased speculation that the nova phenomenon was connected to close binary star pairs.[10] Today it is believed that all novae are binary stars, with a "donor" star orbiting awhite dwarf. The stars are so close to each other that matter is transferred from the donor star to the white dwarf.
T Aurigae is surrounded by anemission nebula (shell) which is roughly elliptical (25 arc seconds by 19 arc seconds in size) and resembles a planetary nebula. Its 3-dimensional shape is similar to a prolate ellipsoid, but it has a central waist, making it shaped somewhat like a peanut.[11] Santamariaet al. obtained images of this shell from 2016 through 2019 and by comparing those images to archival images dating back to 1956, they were able to determine that the shell is expanding at about 0.01 arc seconds per year, corresponding to an expansion velocity of about 350 km/sec.[1]
