HD68988b, with a period of 6.276 days, and a minimum mass 1.68 times that of Jupiter, is the shortest-period exoplanet for which follow-up transit observations have not yet been reported. It is therefore an excellent candidate for the transitsearch.org network, and at the moment, is our highest priority star. The period, eccentricity, and orientation of HD68988b's orbit indicate that there is an 8.5% chance that this planet passes in front of the parent star as seen from Earth. (The size of the parent star has been estimated to be roughly 1.2 times the solar radius).
The star HD68988 is located at a declination of +61 degrees, making it a circumpolar star for many northern hemisphere observers. Over the next several weeks, there are good opportunities for nighttime transit observations at low air-mass. Transitsearch observers in California are preparing to observe the star for a possible transit on the night of October 5/6th 2002 (see predictions chart below). The possible transit on October 12/13th is well-positioned for East Asian observers, while the October 18/19th opportunity is optimally sited for European observations.
Here is a GIF image of HD68988 centered in a 0.3 by 0.3 degree field.
HD68988 has no recent radial velocity observations; the last was November 2001, and it's just becoming visible now (RA = 8hr 18 min). Observers should stay tuned for further updates to the following data.
Here is the most up-to-date orbit:
Period = 6.27613 +- 0.0008 days
Time of periastron = 2451555.2841 +- 0.05
e = 0.1417 +- 0.012
omega = 35.102 +- 4.5
K = 187.098 +- 3.5 m/s
dv/dt = -0.075694 +- 0.007 m/s/day
M sini = 1.68 M_JUP (assumes M_star=1.0 Msun)
# observations = 14
(Keplerian fit by Geoff Marcy)
The planet has made 156.6 orbits since time of periastron=Jan 11
2000, so predictions made with the above orbit are uncertain to about 3 hours or
so. From the 2-body solution, we find that true anomaly f=54.898 (deg) occurs
0.7393 days after periastron passages, which means that the upcoming central
transits will occur (UT):
| HD68988b Transit Centers ( click here for a text file version ) (Ingress/Egress are spaced 1 hour around these central transit times.) | |||||
| Julian Date | Year | Month | Day | Hour | Min |
|---|---|---|---|---|---|
|
2452610.38 |
2002 |
12 |
01 |
21 |
06 |
|
2452616.66 |
2002 |
12 |
08 |
03 |
43 |
|
2452622.93 |
2002 |
12 |
14 |
10 |
21 |
|
2452629.21 |
2002 |
12 |
20 |
16 |
59 |
|
2452635.48 |
2002 |
12 |
26 |
23 |
36 |
|
2452641.76 |
2003 |
01 |
02 |
06 |
14 |
|
2452648.04 |
2003 |
01 |
08 |
12 |
51 |
|
2452654.31 |
2003 |
01 |
14 |
19 |
29 |
|
2452660.59 |
2003 |
01 |
21 |
02 |
07 |
|
2452666.86 |
2003 |
01 |
27 |
08 |
44 |
|
2452673.14 |
2003 |
02 |
02 |
15 |
22 |
|
2452679.42 |
2003 |
02 |
08 |
22 |
00 |
|
2452685.69 |
2003 |
02 |
15 |
04 |
37 |
|
2452691.97 |
2003 |
02 |
21 |
11 |
15 |
|
2452698.25 |
2003 |
02 |
27 |
17 |
52 |
|
2452704.52 |
2003 |
03 |
06 |
00 |
30 |
|
2452710.80 |
2003 |
03 |
12 |
07 |
08 |
|
2452717.07 |
2003 |
03 |
18 |
13 |
45 |
|
2452723.35 |
2003 |
03 |
24 |
20 |
23 |
|
2452729.63 |
2003 |
03 |
31 |
03 |
01 |
|
2452735.90 |
2003 |
04 |
06 |
09 |
38 |
|
2452742.18 |
2003 |
04 |
12 |
16 |
16 |
|
2452748.45 |
2003 |
04 |
18 |
22 |
53 |
|
2452754.73 |
2003 |
04 |
25 |
05 |
31 |
|
2452761.01 |
2003 |
05 |
01 |
12 |
09 |
|
2452767.28 |
2003 |
05 |
07 |
18 |
46 |
|
2452773.56 |
2003 |
05 |
14 |
01 |
24 |
|
2452779.83 |
2003 |
05 |
20 |
08 |
02 |
|
2452786.11 |
2003 |
05 |
26 |
14 |
39 |
|
2452792.39 |
2003 |
06 |
01 |
21 |
17 |
|
2452798.66 |
2003 |
06 |
08 |
03 |
54 |
|
2452804.94 |
2003 |
06 |
14 |
10 |
32 |
|
2452811.22 |
2003 |
06 |
20 |
17 |
10 |
|
2452817.49 |
2003 |
06 |
26 |
23 |
47 |
|
2452823.77 |
2003 |
07 |
03 |
06 |
25 |
|
2452830.04 |
2003 |
07 |
09 |
13 |
03 |
|
2452836.32 |
2003 |
07 |
15 |
19 |
40 |
|
2452842.60 |
2003 |
07 |
22 |
02 |
18 |
|
2452848.87 |
2003 |
07 |
28 |
08 |
55 |
|
2452855.15 |
2003 |
08 |
03 |
15 |
33 |
|
2452861.42 |
2003 |
08 |
09 |
22 |
11 |
Webmaster: Justin Lacy Last Updated: 12-3-2002
