I checked VSX and two papers "Gemini/GMOS Transmission Spectroscopy of the Grazing Planet Can%didate WD 1856+534 b" (https://arxiv.org/abs/2110.14106 and "A transmission spectrum of the planet candidate WD 1856+534 b and a lower limit to its mass" (https://arxiv.org/pdf/2103.15720.pdf) and the transit duration is approximately 8 minutes rather than 8 seconds.
Since this is an approximately 17.2 V magnitude star, I think few amateur observers can acquire images having sufficiently low noise at the short exposure times required. Last fall, at the request of the Delaware Asteroseismic Research Center, we acquired light curves of WD 2326+049 (ZZ Psc) using the 0.6 m Meyer Observatory telescope. This star is12.98 V mag and and we used 30 second exposures through a luminance filter to obtain images with less than 1% uncertainty. Since the apparent intensity of WD 1856+534 b is only about 2.1% of WD 2326+049, obtaining the same precision for a 17.2 V star would take approximately 23 minutes with the 0.6m telescope. Even if one could tolerate much worse precision with such a large transit depth, a single exposure could easily be as long as the transit duration.
Quoting from the abstract of the previously referenced paper, Gemini/GMOS Transmission Spectroscopy of the Grazing Planet Candidate WD 1856+534 b,
"WD 1856+534 b provides a unique transit configuration compared to other known exoplanets: the planet is 8× larger than its star and occults over half of the stellar disc during mid-transit. Consequently, many standard modeling assumptions do not hold."
So this is a unique (so far) grazing exoplanet transit. This paper is worth downloading because this transit offers an extreme example of the flux deficit (depth of the LC dip) not equaling (Rp/Rs)^2, Actually it is never exactly equal (except if a planet completely occults the host star) due to limb darkening, which causes a homogeneously bright disk model of a star to overestimate the ratio. You need to include limb darkening in the transit model to obtain the real ratio of planet radius to stellar radius. There are several different model choices to do this, but I think the one I have seen used most often is the two-coefficient quadratic model. See, for example, section 3.2 of Transiting Exoplanets by Carole A Haswell.
I checked VSX and two papers "Gemini/GMOS Transmission Spectroscopy of the Grazing Planet Can%didate WD 1856+534 b" (https://arxiv.org/abs/2110.14106 and "A transmission spectrum of the planet candidate WD 1856+534 b and a lower limit to its mass" (https://arxiv.org/pdf/2103.15720.pdf) and the transit duration is approximately 8 minutes rather than 8 seconds.
Since this is an approximately 17.2 V magnitude star, I think few amateur observers can acquire images having sufficiently low noise at the short exposure times required. Last fall, at the request of the Delaware Asteroseismic Research Center, we acquired light curves of WD 2326+049 (ZZ Psc) using the 0.6 m Meyer Observatory telescope. This star is12.98 V mag and and we used 30 second exposures through a luminance filter to obtain images with less than 1% uncertainty. Since the apparent intensity of WD 1856+534 b is only about 2.1% of WD 2326+049, obtaining the same precision for a 17.2 V star would take approximately 23 minutes with the 0.6m telescope. Even if one could tolerate much worse precision with such a large transit depth, a single exposure could easily be as long as the transit duration.
Brad Walter, WBY
I wonder does the size of the planet, star or planet's orbit account for such a deep drop in apparent magnitude?
Steve - HSTG
Quoting from the abstract of the previously referenced paper, Gemini/GMOS Transmission Spectroscopy of the Grazing Planet Candidate WD 1856+534 b,
"WD 1856+534 b provides a unique transit configuration compared to other known exoplanets: the planet is 8× larger than its star and occults over half of the stellar disc during mid-transit. Consequently, many standard modeling assumptions do not hold."
So this is a unique (so far) grazing exoplanet transit. This paper is worth downloading because this transit offers an extreme example of the flux deficit (depth of the LC dip) not equaling (Rp/Rs)^2, Actually it is never exactly equal (except if a planet completely occults the host star) due to limb darkening, which causes a homogeneously bright disk model of a star to overestimate the ratio. You need to include limb darkening in the transit model to obtain the real ratio of planet radius to stellar radius. There are several different model choices to do this, but I think the one I have seen used most often is the two-coefficient quadratic model. See, for example, section 3.2 of Transiting Exoplanets by Carole A Haswell.
Brad Walter, WBY
I downloaded the paper and will give it a go.
Steve - HSTG